- Adjust Flavor in the Fermenter: Techniques
Personalize Your Wine
Seven easy ways to adjust flavor in the fermenter
by Steve Bader
Making the perfect wine requires a combination of experience, skill, excellent grapes and good fortune. Skill and experience are things you can acquire over time. But finding the perfect grapes is truly a difficult task. Whether you’re growing your own grapes, buying grapes or buying concentrates, rarely do you get the exact flavor you want from the grape juice in your fermenter.
In operating my retail shop, I find that inexperienced winemakers often believe that all you can do is add yeast to the must and leave the rest to the Wine Gods. They sanitize fermenters, top up carboys and maybe even add some oak chips, but that’s about it. They don’t understand how easy it is to fine-tune a batch and create a flavor they love — even after the wine is in the fermenter!
The most important thing is to open your mind to the creative process. Before you begin, spend some time considering what you want each batch of wine to be. Most winemakers think along the lines of the traditional wine styles, like an oaky Chardonnay from California or a traditional Grand Cru from Burgundy. These are terrific wines, but you might also enjoy some sort of “crossbreed.”
The solution: Simply imagine what you want this wine to be and then go about creating it. Among the most common flavor characteristics to consider are: alcohol strength, acid, tannin, oak, fruit aromas and flavors, body and sweetness.
What follows are my suggestions for personalizing the flavor of your wine. Most of these methods are things you can do after the wine is done fermenting, but before you bottle it. In fact, I find it easier to decide what to do after the wine is about three to six months old. By that time, the wine has settled into something that resembles its finished flavor profile.
With most of these adjustments, it is good to go slow, add a little, taste the wine, and then add more if you want. You can always add more flavor, but it is difficult to take flavor away if you have added too much. A great way of determining what you want to add to your wine is to compare your wine before additions to another wine that has the characteristic that you like. This should help you decide what you want to add to your wine.
When using fresh grapes, it’s common to get fruit that’s slightly low in sugar content. “Chaptalization,” which means adding a little sugar, honey or grape concentrate, will allow you to increase the alcohol content to get the proper balance in your wine. While this is prohibited in Italy and California, it is perfectly acceptable in home winemaking (and in France, by the way).
This adjustment is best done when you first add the yeast to your must. Measure your specific gravity and add the sugar as you see fit. In a five-gallon batch, a pound of sugar, whether it’s honey or table sugar, should raise the ABV (alcohol by volume) roughly three-fourths of a percent. Go easy, as too much alcohol is as bad as too little. Avoid going above 13 percent alcohol by volume (about 25° Brix).
Acid is what makes wines taste tart. It also contributes to their “structure,” so they’re not flabby and lifeless (tannin, glycerol and residual sugars are compounds that also impart structure). In most wine kits, the acid level is a little on the low side, to give you a faster-maturing wine. You can use a titration-method acid-test kit to measure the acidity of the juice or concentrate. If your titratable acidity (TA) is, say, 4 percent (4 g/L) and you want to bump it up to 6 percent, you can adjust it before you pitch the yeast.
When making fruit wines, acid levels are normally very low, and yeast will frequently not ferment the wine without a significant increase in acid content. In these cases, testing the must with a TA kit — again, before you add the yeast — will help you to determine the amount of acid to add. You may still add more acid later from a flavor standpoint. (You can buy one of these simple kits at any good home winemaking supply shop.)
There are three types of acid in powder form. Tartaric acid is the primary acid in grapes. Citric acid is the main acid that comes from oranges and lemons. Malic acid is the leading acid in apples and pears. You can also buy an acid blend that’s a combination of these three acids, normally blended in equal portions.
To increase your wine’s acidity, I would suggest adding about 1/4 teaspoon per gallon to start. Use a blend or choose the acid you think best flavors your wine. Tartaric acid works best for grape wines; citric acid is good for mead; and a blend of all three acids suits fruit wines.
A note on timing: It’s best to adjust acid before you pitch the yeast. Otherwise, yeast that have acclimated to one acidity level may react poorly to a sudden acid shock. This is particulary true if your wine will undergo malolactic fermentation; malolactic bacteria are exceedingly sensitive to acid conditions.
You can also reduce the acidity if your wine is too tart. Potassium carbonate is very effective in reducing overall acidity, and will not give your wine a chalky taste like calcium carbonate might. Go easy with it, since it reduces acidity with a small addition. Start with 1/2 teaspoon for a five-gallon batch and add in 1/2 teaspoon increments until you’re satisfied.
Tannin is the naturally occurring astringency found in grape skins, often described as a “sandpaper” feel in your mouth. Tannin is primarily found in red wines, since they usually ferment with the skins. Whites contain a lot less tannin than reds, since they’re often crushed and pressed the same day. Nearly all kit wines are low in tannin, again for a faster maturing process, so many red wines can be improved by adding some tannin to the fermenter.
I would add powdered tannin at the rate of roughly 1 teaspoon of tannin per 5 gallons. Add the tannin to 2 cups of boiling water to dissolve, and then add about 1/2 cup of the tannin water at a time, gently mixing it into the wine, tasting the wine after each addition, and stopping when the tannin level is about what you want. Tannin flavors do decrease with time, so this addition can be a bit tricky.
Oak barrels are expensive and difficult to use in batches less than 60 gallons. As a home winemaker, oak chips, oak powder or liquid oak flavoring can be added get the oak flavor you desire. Again, wine kits tend to be a little low in oak flavor, so you can add more oak chips to simulate the flavor and aroma that wineries get from aging wine in an oak barrels.
I would add about 1 cup of oak chips to 2 cups of boiling water, let them soak for a half-hour, and then add the chips and water to your wine. Sample the wine every day, at the minimum, to evaluate the flavor transfer, and siphon the wine off the chips when you think you have enough oak flavor. Oak flavor does diminish with time, so it’s acceptable to slightly over-oak.
Oak chips and powder come in several different types, including untoasted American oak, toasted American oak, and French toasted oak. They all will give a different flavor to your wine, so smell them before you buy and pick the one that best suits your style.
Regardless of the wine you are making, you may want to increase the fruit flavor and aroma. Small bottles of natural fruit flavoring are available that have no sugar, just the great fruit aroma. These can be added to taste just a few days before bottling.
Available flavors inclue blackberry, raspberry, cherry, blueberry, boysenberry, peach, cranberry, mango, hazelnut, apple and apricot. The flavors are strong, so a little goes a long way here. I’d start with two ounces for a five-gallon batch.
Choosing a fruit flavor is a matter of personal taste. Still, I’ll make two suggestions: Peach goes nicely with a Chardonnay, while blackberry adds a fine flavor to a Merlot.
If your wine has a thin taste, you can add a body builder called “finishing formula” (glycerin). This is a thick, clear liquid that adds body and a small amount of sweetness to the wine. It also can mellow out some harsh flavors. Use it sparingly, as a little goes a long way. Glycerin is added to taste, so I would add it in increments of about 1 ounce per 5 gallons of wine. Taste and add more if you like.
If your wine is too dry when you are ready to bottle, you can add sweetness to the wine to bring it up to the level that you would like. There are several different ways of adding sweetness to your wine.
Some wine kits contain a finishing pack, which is a liquid concentrated grape sugar. You could also buy “wine conditioner,” a liquid sugar concentrate combined with sorbic acid, which prevents wine from re-fermenting in the bottle.
You can make your own sugar concentrate by boiling a cup of water with two cups of sugar. If you make your own sweetener, you must add Sorbistat K (potassium sorbate and sorbic acid) to prevent the sweetener from starting a re-fermentation. You should also add some campden tablets (potassium bisulfite) to inhibit oxidation.
Remember, this is your wine! You’re limited only by your imagination. Take a sip from the fermenter, and if you think adding a flavor will improve the wine, give it a try and have fun!
Steve Bader is the owner of Bader Beer and Wine Supply in Vancouver, Washington. He wrote “Confessions of a Wine Judge” in the Spring 2000 issue of WineMaker.
• Alcohol: Add sugar, honey or concentrate to increase the alcohol by volume. Don’t go above 13 percent ABV.
• Acid: Add tartaric, citric, malic or blend; start with 1/4 tsp. of powder per gallon.
• Tannin: To increase the astringency, add powdered tannin at 1 tsp. per 5 gallons.
• Oak: 1 cup of chips should flavor a batch in a few days.
• Fruit: Natural flavorings come in many varieties; start with 2 oz. for 5 gallons.
• Body: Add glycerin to your batch in 1-oz. increments.
• Sweetness: Use a “finishing pack,” wine conditioner or make your own sugar concentrate to sweeten the wine.
- Delestage Fermentation: TechniquesLearn how to produce approachable young red wines using delestage fermentation -- a French winemaking technique most home winemakers have never heard of.
As an enophile, I enjoy almost every type and style of wine. However, my true love is — and always has been — big, bold, oak-aged reds, the type built for the long run. My favorites include rich, peppery California Cabernet Sauv-ignon, tannin-rich Piedmontese (Italian) Nebbiolo or chocolate-scented Australian Shiraz (known as Syrah in North America).
As a home winemaker, my goal has always been to replicate such world-class wines, which could be cellared for many years. I macerate my reds 14-21 days, with frequent pump-over or punching of the cap for maximum phenolic extraction, and age them 6-12 months in American and French oak barrels. I typically bottle three years after the vintage and drink them over the next five to seven years.
Maceration is the process of soaking or fermenting red wine with its grape solids. The cap is the layer of grape solids that floats to the top of the wine during fermentation. Pump-over and cap punching are cap management techniques used in red winemaking to extract phenolic compounds — such as color pigments, tannins and flavors — from the grape solids, and to keep the grape solids soaked to prevent spoilage. (Refer to “Master Maceration” in the Fall 2001 issue of WineMaker for more information on maceration and cap management.)
The drawback of such wines is that they can be overly astringent in their youth, particularly those that have spent some time in oak barrels. They are not approachable before a few years of aging, which is required to tame the tannins. As my palate evolved, I wanted the same style of wine, but one that would be more approachable when young and exhibit a fruitier nose with a rounder, less astringent mouthfeel. The solution? Delestage fermentation.
Delestage is a fermentation and maceration technique used in red winemaking from grapes that gently extracts phenolic compounds by oxygenating the juice to produce a softer, less astringent wine exhibiting more fruit character. (The word “delestage” is from the French “délestage.” It means “lightening,” in reference to the separation of juice and grape solids. It is pronounced day-leh-staj.) In fact, Dr. Bruce Zoecklein’s research at Virginia Tech has demonstrated that delestage-fermented wines have a lower concentration of tannins and a higher concentration of esters, key compounds that contribute fruitiness (Leahy, 2000). Given the lower concentration of tannins, delestage-fermented wines will generally not age as long as traditionally fermented, tannin-rich, oak-aged wines, but this is strictly a matter of style and preference.
Although many wineries use this technique, particularly in making Pinot Noir, delestage is practically unknown to home winemakers because its practice and benefits are not often covered in the home winemaking literature. And being labor intensive, delestage is a process best suited for commercial wineries outfitted with the appropriate equipment. However, a simple process adaptation to home winemaking can significantly reduce the effort and still provide the benefits of delestage.
What is delestage?
Delestage is a two-step “rack-and-return” process in which fermenting red wine juice is separated from the grape solids by racking and then returned to the fermenting vat to re-soak the solids. This step is then repeated daily.
Racking the fermenting juice oxygenates, or aerates, the wine and softens the astringent tannins through oxidation. It also stabilizes the wine’s color. Racking during maceration and fermentation is the underlying difference from traditional maceration-fermentation, in which the juice ferments under a layer of carbon dioxide (CO2) gas and is seldom aerated until racked at the end of fermentation. Pump-over (the re-circulation of wine from the bottom of the fermentation vat to the top to soak the grape solids) is sometimes used to aerate the wine but does not provide the same effects as delestage because the wine is never separated entirely from the grape solids. (Refer to “Understanding Phenolics” on page 38 in this issue of WineMaker for more information on tannins and effects of operations such as pump-over.)
During delestage racking, the cap slowly falls to the bottom of the vat while the wine is allowed to drain completely under the weight of the grape solids. Once the wine is completely racked, a portion of the grape seeds is removed to avoid imparting the harsh tannins in seeds to the wine.
Following racking, the grape solids are allowed to settle separately from the fermenting wine for one to two hours or more depending on the size of the fermenting vat. The fermenting wine is returned to the vat over the cap using a gentle, high-volume pump to completely soak the grape solids for maximum color and flavor extraction while minimizing extraction of harsh phenols.
This process is repeated daily until the end of fermentation. As fermentation progresses, more seeds are released from the grapes, a portion of which can be removed during each racking operation.
An advantage of delestage is that the rack-and-return operation favors juice extraction from grape solids and increases free-run yield, and therefore requires less pressing of the solids at the end of fermentation. Macerating enzymes can also be used to help break down cell walls of red grapes for a more gentle extraction of phenolic compounds, thereby increasing the effects of delestage.
For the home winemaker
Delestage can be made to be a relatively easy process for home winemakers while still achieving the same benefits.
The fermentation vat should be equipped with a faucet at the bottom. The vat should be positioned in a slanted position to allow fermenting juice to drain freely from the faucet during the racking operation while allowing the removal of as many seeds as possible. You will not be able to remove all the seeds; expect to remove up to one-third by the end of fermentation. Use a standard 5-gallon (19-L) pail for receiving the wine being racked along with a sieve to separate seeds and other grape solids from the wine.
Have sufficient small demijohns or carboys for fermenting wine during the racking and settling period. Use small 5- or 6-gallon (19 or 23-L) glass containers — or better yet, plastic carboys — as you will need to lift these up above waist level during the “return” operation. Get an extra pair of hands to help you and avoid injuring your back. Commercial wineries use gentle, high-volume pumps to displace large volumes of wine during delestage. The much smaller volume in home winemaking does not warrant the cost of a pump. In addition, special paraphernalia or fermentation tanks with special screens are required to separate the seeds from the juice. Home winemaking pumps are not designed for this type of juice handling.
When planning capacity and carboys required, figure a total yield of 7 to 8 gallons of wine per 100 pounds of grapes (6–7 liters per 10 kg of grapes) on average. The yield will progressively increase following each daily racking operation. The maximum total yield depends mainly on the grape variety and fruit quality, as well as on the use of enzymes.
To perform delestage, let fermentation start and allow it to proceed until the cap forms on top of the fermenting juice. This may take up to two or three days depending on the temperature of the fermentation area. Adjust the temperature to avoid having the fermenting wine exceed the mid- 80s (30° C), which could otherwise cause fermentation problems. And be sure to protect the must with a heavy tarpaulin to keep fruit flies out and to protect it from spoilage bacteria during fermentation.
Once the cap has formed, place the sieve and pail under the faucet, then open the faucet slowly and completely until the pail is filled. Close the faucet, transfer the wine to a carboy, and remove whatever seeds have been collected in the sieve. Repeat this until all the wine is completely drained.
During racking, the cap will slowly and gradually fall to the bottom of the vat. While the cap rests at the bottom, more wine will drain under the weight of the grape solids. Leave the faucet open with the pail under it until no more wine drains. Depending on your grape volume, this may take up to one hour or two, possibly more. Transfer this wine to a carboy, and then ensure that all containers are properly topped up and protected with fermentation airlocks.
At the end of the racking period (i.e. when no more wine drains), wine in the carboys must be returned to the fermenting vat. This is the part of delestage where an extra pair of hands will be required. Alternatively, you can use a high-volume home winemaking pump in this operation because the wine is free of large solids and does not require any special handling. The idea is to douse the grape solids quickly and thoroughly so that the wine rises faster than the solids while pouring or pumping. This maximizes interaction between the cap and the wine, and optimizes the effects of delestage. If pouring from a carboy, have someone help you to lift and hold the heavy container. If you make more than 50 gallons (200 L) per year, consider investing in a good pump if you intend to ferment using delestage.
Repeat the rack-and-return procedure each day or every other day. Delestage should be used in conjunction with cap punching, i.e., continue breaking and submerging the cap as usual, two or three times daily, to maximize color extraction and protect the wine from spoilage bacteria.
Maximizing the benefits
The benefits of delestage — higher concentration of fruity flavors, softer tannins and more stable color — can be optimized through the use of selected fermentation yeasts and macerating enzymes.
Use a low-foam yeast specifically recommended for reds where supple mouthfeel and concentrated fruit aromas are desired. Foamy yeasts tend to inhibit the benefits of delestage. Brad McCarthy, winemaking consultant at White Hall Vineyards in Charlottesville, Virginia, recommends and uses Lallemand’s low-foaming Lalvin D254 yeast in crafting their reds (Leahy, 2000). D254 yeast is particularly recommended for Syrah-based wines and adds a touch of spiciness. If you cannot find this yeast, suitable substitutes include Lallemand’s Lalvin RC212, highly recommended for Pinot Noir-based wines, Red Star’s Pasteur Red, highly recommended for Cabernet Sauvignon-based wines, Wyeast’s Pasteur Red or White Labs’ Cabernet Red Wine (WLP760).
Macerating enzymes can improve color stability and enhance mouthfeel for smoother reds through a more gentle extraction of phenolic compounds. Macerating enzymes are added to the must before the start of fermentation; they do their work during the maceration phase in red winemaking. Two examples of macerating enzyme products on the market recommended for wines to be fermented by delestage are Lallemand’s Lallzyme EX or Scott Laboratories’ Scottzyme Color Pro.
Since these products are mainly used in commercial winemaking, they are mainly available in sizes larger than most home winemaker’s needs. Lallemand’s Lallzyme EX is now available in a small format good for 5-gallon batches. Alternatively, you can buy larger formats and share with fellow home winemakers. A package can be used for two vintages if it is stored in a well-sealed container in a refrigerator. Be sure to follow the manufacturer’s instructions and recommended rate of addition.
Leahy, Richard. “Délestage Fermentation: From Bitter to Better Reds.” Vineyard & Winery Management. Sept./Oct. 2000, Vol. 26, No. 5.
Daniel Pambianchi is the technical editor of WineMaker magazine.
- 10 Winemaking Techniques You Should Know
The difference between an average wine and an awesome wine might be applying the right technique.
Q. What is the difference between good and superlative wines?
A. The WOW! factor. A good wine offers everything that the varietal or style is meant to provide. While it can provide great balance and drinking pleasure, perhaps it doesn’t quite “jump” out at you with oodles of fruit, aroma and flavor complexities, or a lingering finish.
A superlative wine, on the other hand, is packed with charming aromas and concentrated flavors that linger on and on, and provides more than simply great drinking pleasure; it excites the senses. A great wine makes the palate dance; it makes you close your eyes as you inhale the multitudes of subtle and harmonious aromas. It creates a lasting memory. It’s the type of wine that you will still talk about years from now.
Sure you can make good wines from true and tried recipes by simply following a set of instructions, but you’ll need to go beyond that to craft memorable wines. This is where you need to leap from the science into the art of winemaking.
Here are 10 proven winemaking techniques and practices you should know and implement if you want to make that leap.
SEEK THE BEST FRUIT, JUICE OR CONCENTRATE It is often said that wine is made in the vineyard. Not literally, of course, but rather, to make great wine you must start with the best fruit possible. You can make great wine from great raw material, but you can’t make great wine from poor or average raw material. (And you can also make poor wine from great raw material.)
So seek out the best fruit, juice or concentrate (kit). All too often, we settle for average raw material because we hurry into the excitement of making wine, but the quality will percolate its way into the final product. And you get what you pay for.
Buy grapes from a reputable supplier to ensure you are getting the varietal you are paying for. Grapes must look healthy with no rot, mold or shriveled bunches. Large berries in small-berry varietals, such as Cabernet Sauvignon, Pinot Noir and Chardonnay, may point to a poor vintage with juice having a high proportion of water, which will dilute concentration of sugar, color (in reds), acidity, aromas and flavors. Small berries will yield less wine, but with richer concentration.
RUN OFF JUICE Higher concentration of total dissolved solids in a juice, or concentrated juice kits, results in a richer wine. If you make red wine from grapes, here is an amazingly simple trick to increase concentration of color, aromas and flavors, and enhanced structure for more mouthfeel and body — run off some juice as you crush.
Immediately after crushing the grapes, run off 10% or more of juice depending on your desired style of wine. A smaller volume of juice will then macerate with the same amount of grape skins, therefore increasing the concentration of phenolics extracted, i.e. color pigments, tannins and flavor compounds, from the skins.
The free-run juice is simply vinified as white wine. Alternatively, you can let the juice macerate for up to 24 hours (depending on the desired depth of color) to make a rosé wine, and then run off the juice.
FERMENT WITH DIFFERENT YEAST STRAINS Ah! One of the great secrets of winemaking . . . yeasts. Unfortunately, as amateurs, we do not seem to exploit the full potential of the many available yeast strains. All too often, little thought is put into yeast selection. At best, we choose a strain depending on the expected fermentation environmental conditions, such as temperature and expected alcohol yield.
Yeast strains do, however, play a much more significant role beyond simply fermenting sugar into alcohol. No two strains are meant to yield the same results; different strains impart significantly different aromas and flavors. Some strains are better suited for specific varietals, and you may have come to develop a preference for a specific strain, but why not try fermenting separate batches of the same wine with different yeast strains?
If your winemaking also involves barrel fermentation, try different strains in barrels in addition to fermentation in inert containers (i.e., glass carboys or stainless steel tanks). Following fermentation and throughout the maturation phase, taste and assess the wines separately and see how different each batch has turned out. Then, you can try blending different combinations of wines fermented using different strains until you have a wine that is greater than the sum of the parts. The results will surely surprise you.
USE NUTRIENTS AND ENZYMES The use of specialized nutrients and enzymes isn’t a common practice in home winemaking, either because their use is misunderstood or they are dismissed as “harmful additives.” Quite the contrary, nutrients and enzymes are not harmful; they are actually beneficial.
Yeast requires nutrients, particularly in musts from grapes and fresh juice where there may be a nutrient deficiency or imbalance. For example, high-sugar musts will require nutrients as yeast will be struggling in the presence of high sugar concentration.
There are three types of nutrients: yeast rehydration nutrients that are added during yeast rehydration; complete yeast nutrients which provide a blend of complex nutrients, added to the must at yeast inoculation time; and, natural yeast derivative nutrients that can be added to the must or wine. Likewise, malolactic bacteria require nutrients for a successful MLF as the wine may not satisfy the bacteria’s high-nutrient needs.
Enological enzymes are proteins that catalyze reactions involved in enhancing wine stability or improving overall quality. For example, pectic enzymes can degrade pectins to provide stability against cloudiness or to improve fining and filtering efficiencies, while macerating enzymes can be used to increase the rate of phenolic extraction for improved color and tannin stability, or to improve press yields.
PERFORM DELESTAGE If you enjoy big, bold red wines, but would like to drink them earlier in their youth without the need for years of cellaring, delestage might be the answer for you if you make wine from grapes. Delestage is a fermentation and maceration technique, often used in crafting Pinot Noir, which gently extracts phenolic compounds by oxygenating the juice to produce a softer, less astringent wine exhibiting more fruit character.
Author Richard Leahy explains this in his book “Délestage Fermentation: From Bitter to Better Reds.” Often referred to as the “rack-and-return” process, fermenting red wine is separated from the grape solids by racking and then returned to the fermenting vat to re-soak the solids, and then repeated daily. The result is a wine with a lower concentration of tannins and a higher concentration of esters that is much more approachable in its youth.
During the racking phase of the process, the cap is allowed to slowly fall to the bottom of the vat while the wine is allowed to drain completely under the weight of the grape solids. Once the wine is completely racked, a portion of the grape seeds is removed to avoid imparting harsh tannins.
Following racking, the grape solids are allowed to settle separately from the fermenting wine for 1–2 hours or more depending on the size of the fermenting vat. The fermenting wine is returned to the vat over the cap using a gentle, high-volume pump to completely soak the grape solids for maximum color and flavor extraction while minimizing extraction of harsh phenols.
This process is repeated daily until the end of fermentation. As fermentation progresses, more seeds are released from the grapes, a portion of which can be removed during each racking operation.
Refer to “Do the Delestage” in the June-July 2003 issue of WineMaker for detailed instructions on implementing delestage in the home winery.
ADD CHARACTER TO WINE The use of oak barrels is as old as winemaking. Aside from their ideal properties for storing and shipping wine in ancient times, the true benefit of barrels is that they add character, specifically, aromas and flavors that complement wine perfectly like no other type of wood or vessel. And the controlled micro-oxidation, through the barrel wood and staves adds further complexity. The benefits of micro-oxidation can only be achieved using barrels, however, there are several oaking solutions to impart oak aromas and flavors to replicate that style of wine you like so much that does not require a hefty investment in barrels. You can choose from oak chips, beans and segments for oaking in as little as one week, as well as staves which are ideal because they impart oak more slowly as less end grain is exposed on the wood.
So use oak if you want to nuance that delicate Pinot Grigio with hints of oak and vanillin and to add more character, or if you like rich and full-bodied Chardonnays and Bordeaux-style blends, or delicate Pinot Noirs. But be careful not to over-oak; you don’t want the oak to mask other aromas and flavors.
And for those of you living in northeastern US, around the Finger Lakes area, and the Niagara Region of Canada, and that have to contend with the dreaded Multi-colored Asian Lady Beetle (MALB) taint responsible for imparting asparagus, rancid peanut and bell pepper aromas, oaking has been shown to mask such aromas quite successfully depending on the extent of taint.
Refer to “Barrels” in the April-May 2006 issue of WineMaker for more information on the use of oak.
CARRY OUT MLF Malolactic fermentation (MLF) is the partial or complete transformation of naturally-occurring, sharp-tasting malic acid (think green apples) found in juice and wine into the softer lactic acid (think milk-based products) induced by lactic acid bacteria. As malic acid is stronger and is converted in roughly equal proportions of lactic acid and carbon dioxide gas (CO2), there is a corresponding decrease in total acidity (TA), making MLF ideal as an acid-reduction technique, particularly in reds. In whites, it is also responsible for the common buttery/nutty flavor found in malolactic-fermented Chardonnays.
MLF is, however, not recommended in all wines. Most reds will benefit while only certain whites, such as Chardonnay or highly-acidic varieties will benefit. MLF can excessively reduce acidity in whites or impart non-complementary flavors that make the wine flat and unpalatable, particularly in aromatic whites, such as Riesling. Concentrate wine kits are processed to avoid acidity adjustment and MLF altogether, and so, it is not desired nor recommended in such wines.
A dry- or liquid-format malolactic culture is recommended to initiate MLF instead of trying to rely on unpredictable and potentially damaging indigenous bacteria. For some added complexity, carry out the MLF in barrels in conjunction with lees stirring.
STIR THE LEES If you want to add aroma and flavor complexity to a refreshing, light-bodied Sauvignon Blanc, or for increased richness in a Burgundian-style or full-bodied California Chardonnay, try stirring the lees, which are the dead yeast cells that form at the bottom of carboys or barrels during fermentation.
Lees stirring, known as bâtonnage in Burgundy, refers to the practice of stirring the dead yeast cells back into suspension during the maturation period, hence why it is often referred to as sur-lie aging, French for “on the lees”. It is most often practiced in white winemaking.
The stirring is accomplished using a special cane or stirring rod according to a stirring schedule determined by the winemaker based on desired style, for example, once daily starting at the end of both fermentations, and then progressively reduced to once a week for a maximum total duration of 12 months. A word of caution though, only fine lees are beneficial; gross lees are rich in spoilage organism nutrients and contain a myriad of other heavy solids, such as pulp and grape skin fragments that may contain sulfur, from vineyard spraying, or sulfur dioxide (SO2) from sulfite additions, all of which can have a negative impact on wine quality. Extended contact with gross lees can cause a (chemical) reduction of sulfur-containing compounds, which can lead to highly undesirable flavors such as a rotten-egg smell. To avoid such spoilage, rack wine off its voluminous gross lees early, i.e., right after the vigorous phase of alcoholic fermentation.
Refer to “Stirring the Lees” in the August-September 2006 issue of WineMaker for more information.
TASTE, TASTE, TASTE AND BLEND The need to taste and taste again extensively cannot be over-emphasized. You need to be patient and nurture wine from fermentation to bottling. And throughout this aging and maturation period, you should taste the wine regularly to assess its evolution and also as a preventative measure against any spoilage that may be setting in. This is particularly true of wines that are fermented or aged in barrels because you need to control the amount of tannins and oak aromas and flavors extracted, and again, to prevent any spoilage as the risk increases now that the barrel will have some headspace as the wine evaporates.
When tasting wine, take a sample from each and every carboy and barrel; don’t assume that wine is developing similarly in two barrels. It is particularly important to taste wine after key operations, such as fermentation, MLF and fining since these will invariably alter TA, pH, structure and body. Perform key measurements such as TA, pH and free SO2 at a minimum to try and correlate your olfactory and gustatory observations with the analytical data.
As soon as you detect something wrong with the wine or you feel some adjustments are required, take immediate corrective action by first performing bench trials on a small sample before addressing the whole batch.
Once you have tasted and “corrected” all batches, decide if you want to blend any batches back together or if you want to try blending different varietals. Many of the great wines of the world are blends, so don’t limit yourself to making strictly varietals. Try various blends of different wines in various percentages of each until you get something you like. Keep in mind that the over-arching principle is to always maintain balance between perceived sweetness, acidity, alcohol and tannins in the case of reds.
Refer to both “Balance in Wine” and “Achieving Balance” in the February-March 2005 issue of WineMaker for more information.
STABILIZE WINES Jancis Robinson explains in “The Oxford Companion to Wine (Third Edition, 2006)” that stabilization is the winemaking practice of safeguarding juice and wine from the time the must is handled in preparation for vinification, through vinification and aging, to bottling and until consumed, and includes two sorts of operations: one to counter physical and chemical changes and another to counter microbiological changes.
Specific processes to counter physical and chemical changes include racking, fining (clarification), filtration, chill-proofing and heat stabilization, while processes to counter microbiological changes include adding preservatives and stabilizing agents and membrane filtration.
Before undertaking any form of stabilization, you need to understand the wine’s chemistry, style and history to make informed decisions. In winemaking from concentrates, this is simple as the manufacturer has done extensive testing and will typically recommend fining or filtration and the addition of sulfite and possibly potassium sorbate. In general, this is not sufficient when making wine from grapes or fresh juice because these would not have been treated against potential instabilities, such as against cold and hot temperatures. Here are some guidelines.
All wines should be protected with a nominal free SO2 level of approximately 35 mg/L, adjusted up or down based on pH. The higher the pH, the less effective SO2 is, hence more sulfite is required. Use the Sulfite Calculator at www.winemakermag.com to guide your sulfite additions.
Early-drinking reds and whites should be fined or filtered, perhaps both if a wine is to be bottled and drunk soon.
A wine that has not been cold stabilized will throw tartrate crystals — potassium acid tartrate, the potassium salt of tartaric acid — when it is subjected to cold temperatures. Similarly, a wine with excessive protein concentration and which has not been heat stabilized will become cloudy if subjected to hot temperatures. Therefore, you need to test all wines for cold and heat (protein) stability and treat accordingly.
To test for cold stability, place a sample bottle of wine in a cold refrigerator or freezer at a temperature of as low as -4° C (25° F) for three days. At the end of the test period, hold up the bottle against a bright light, invert it and look for tartrate crystals that fall down. If there are no crystals, the wine is considered cold stable and requires no further processing against tartrates. If the test is positive, then the wine must be chill-proofed by placing the wine in cold storage for a couple of weeks or treated with metatartaric acid.
To test for heat stability, heat a wine sample at 80° C (176° F) for 10 minutes and then place it in a freezer for several hours. Retrieve the sample and let it warm up to room temperature; if it shows any sign of haze or precipitation, then the wine is not protein or heat stable and requires a bentonite treatment.
Refer to “Hot and Cold Hazards” in the October-November 2007 issue of WineMaker for more information on cold and heat stabilization.
For wines that will have any appreciable amount of residual sugar, for example over 5.0 g/L (0.5%), you will need to add potassium sorbate to inhibit renewed fermentation in the bottle. For added peace of mind, if the wine is to be cellared for an extended period of time or if the wine has undergone MLF and the use of sorbate is not recommended, membrane filtration is the solution.
Membrane filtration is a specialized type of filtration used to achieve microbial stabilization to safeguard wine against microbiological changes or spoilage due to unwanted or undesirable yeasts and bacteria that may start feeding on residual sugar, malic acid or other nutrients.
Refer to “Should I Membrane Filter My Wine” and “Microbial Stabilization” in the August-September 2007 issue of WineMaker for more information.
If membrane filtration is beyond your means or abilities, you can use lysosyme — a specialized enzyme effective in suppressing spoilage bacteria after MLF and achieving microbial stability, particularly in high-pH wines where more sulfite is required to guard against spoilage.
Daniel Pambianchi is the author of the recently updated and revised reference, “Techniques in Home Winemaking” (Véhicule Press, 2008). He is a frequent contributor and “Techniques” columnist for WineMaker, as well as the general manager of Maleta Estate Winery.
Cab and Syrah, together? We explain the rationale behind this blend and the best procedures for making it at home.
Home winemakers often resort to a little blending to improve their wines — to add a little more body, tweak the acid balance or deepen the color, or just because it takes one more gallon of something to fill that barrel. But many of the world’s great wines, and maybe even a higher percentage of the world’s pretty good wines, are designed as blends from the start.
Think Bordeaux, where two grapes in the mix are a kind of minimum and four or five not uncommon. Take Châteauneuf-du-Pape, with 13 grape varieties (and counting) allowed in the soup. Or take Australia’s signature blend, Cabernet-Shiraz, sometimes known as Shiraz-Cabernet, an Oz staple with a lot to recommend it.
The first time I encountered this blend, early in the Australian invasion of US wine shelves, I thought it seemed rather odd. Why would you blend two big wines, each capable of standing on its own? Wouldn’t that make something overly heavy, clumsy, fighting with itself? But after some tasting, I figured out the underlying logic of this blend: the Cabernet Sauvignon provides the tannin structure and therefore the basis for longevity, and the Shiraz (Syrah for us Northern Hemisphereans) gives fleshy fruit from day one. The result is something a lot of wines claim, but often don’t really deliver: drinkability when young, right after release and the potential to mature in the bottle for several years.
In my experience, the combination of these two powerhouse wines is anything but heavy, not the overpowering sum of the parts that might be expected. Instead, Cab-Shiraz often comes across as lighter and livelier than either component. It’s as though the relative austerity of the young Cabernet diminishes the syrupiness of the Syrah, keeps it from being cloying — which some mass-market Aussie Shiraz can certainly be — while the fruitiness of the Syrah keeps the tannin from the Cabernet on a short leash. Somebody ought to cross these two grapes and see what happens.
Meantime, certainly for home winemakers, setting out to do a Cabernet-Shiraz blend is a great learning exercise in variety-specific winemaking. In many respects, making red wine is making red wine, but the nuances of difference in the grapes ultimately call for differences in cellar technique, as well as site selection and viticulture. Especially during the hectic week or ten days of fermentation, the common path to dryness has a lot of detours on one side or the other, in things like yeast preferences, fermentation temperature and the timing of pressing. Doing them side by side, even if a couple weeks apart, is a terrific hands-on lesson in steering wines in particular directions. In a short few days, the two approaches accomplish quite different things — and can end up in one happy marriage of a wine.
For the purposes of this article, the things that apply to all red wines — the importance of sanitation and clean equipment, the need for testing of basic grape and wine chemistry, frequent monitoring, topping off storage vessels, keeping SO2 levels in range — will get relatively scant attention. The focus will be on how this modern classic blend starts on two tracks and finally comes together on one — without crashing.
I know it’s fashionable these days to insist on “picking on flavor, not on the numbers.” But some numbers are just not helpful for this particular wine style. Cab-Shiraz blends do rely on ripe flavors, but tend to fall apart and get blowsy and flabby once they get much past 14% alcohol, which means once the grapes get beyond 26 ºBrix. The 24.5– 26 ºBrix range is the right target. If one of the grapes is a little high, fine, it can average out; but if both are pushing the envelope, some dilution with acidulated water (6 grams of tartaric per liter of water) is recommended.
There is no way to know ahead of time the “perfect” blend of your batch of Cabernet and your batch of Syrah — you’d have to taste them as finished wines, except that you have to order the grapes first. Aiming for an even split, equal parts of each, is a pretty good bet, especially if you get enough grapes to have a couple gallons of each available for fine-tuning the blend.
This is a wine that certainly benefits down the road from barrel aging — maybe a year in a once-used 30-gallon (113-L) French or American barrel — which means buying enough grapes to fill at least a small barrel. But it can also work just fine in a carboy with some oak cubes. One useful variation on the project would be to get enough grapes for three carboys — a little over 100 pounds (45 kg) of each variety — and then compose one that’s 50:50, one that’s two-thirds Cabernet and one that’s two-thirds Syrah. You can always blend them together one more time for the final bottling, but enjoy the differences in the meantime.
Don’t let the fact you know it will grow up to be a blend fool you into thinking you can use second-rate grapes, as though somehow the process of combining the elements will overcome the flaws in the parts. You want grapes good enough to make good wine on their own. Get rid of any rotted grapes and other stray vegetable matter before crushing; this wine works best when it’s on the bright, clean side, not the earthy, stemmy side. The grape/wine chemistry should be in order — not just at reasonable sugar levels, but a pH down near 3.5 and acidity at or a little north of 6 grams per liter at the start of fermentation. If the pH is significantly high or the acidity low, fix it at the start.
For both grapes, crush as gently as possible, trying not to shred the skins or chew up the stems or crush any seeds. More and more, gentle crushing — up to and including no crushing at all, just destemming — is the dominant trend at the moment for most red winemaking, and it certainly helps with Cab-Shiraz, where harsh notes can really stick out. Right after crushing, do a small, preventive addition of SO2 — 25–50 parts per million—and consider a small dosage of lysozyme (50–100 parts per million) to fight off unwanted lactic bacterial activity. (However, be aware that lysozyme can interfere with malolactic fermentation, or MLF.)
Here the paths start to diverge. Keep reminding yourself, the idea is to get structure out of the Cab, fruit out of the Syrah. For the Cabernet Sauvignon, Bordeaux-friendly yeast strains are good choices, since they have been selected for their ability to extract goodies from Cabernet and the rest of that family of gapes. The Bordeaux Red strain is an obvious choice; MT yeast advertises its ability to enhance wine structure; D80 is another good candidate.
For almost all red grapes, Australian winemakers tend to prefer front-loaded fermentations: getting the temperature up to its peak early in the fermentation cycle, then letting the must cool gradually as dryness approaches. The benefits of this approach are that the key phase of extraction of color and flavor compounds from the skins happens through temperature, while the ethanol level is still fairly low —instead of concentrating extraction at the end, when both temperature and ethanol (which favors tannin extraction) would be high. In this way, getting temperature to peak early is actually less aggressive than having it peak late, and since nearly all the goodies come out in the first few days, the option of pressing a bit early, a little before dryness, is available, limiting tannin accumulation.
In the Cabernet case, you’ll want to get the temperature up to 85 ºF (29 °C), even close to 90 ºF (32 °C), for a day or a day and a half, then slowly cool down. For most home winemakers, this means applying heat bands around the fermenters and perhaps covering the tops with other blankets to provide further insulation. With periodic punchdowns, the wine should be close to dryness in about a week.
For the Syrah, there is of course the eponymous Syrah yeast, along with another popular strain, D254. Many winemakers, commercial and amateur, have been experimenting with wines composed of batches made with D80 and other batches made with D254, the result at least potentially being a blended wine with more concentration, intensity and body. At the other extreme, if your goal is to maximize the fruity, youthful side of a Cab-Shiraz blend, try using something like RC212, often a Pinot Noir yeast choice. The Syrah target temperature would be a little lower, from 80 ºF (27 °C) to maybe 85 ºF (29 °C), again attained early in the fermentation cycle.
Another technique worth trying for the Syrah piece of this puzzle is délestage, or what the Australians call rack and return. The procedure, briefly, involves lifting the floating cap of the Syrah sometime in mid-fermentation, depositing it in another clean fermenter, and exposing both the transported cap and the remaining liquid to air for a short period, maybe 2–4 hours. Then pour the liquid back over the grapes in their new home, leaving a lot of the seeds behind, and re-commence the daily ritual of punchdowns.
The virtues of this deconstruction/reconstruction are twofold. First, it exposes everything to oxygen, which is useful at this stage of fermentation and helpful for getting the operation through to dryness. Second, it reduces the seed content in the mix. This part is a bit controversial: seed tannin has for some time gotten blamed for imparting harsh and bitter flavors to wine, though some recent research casts doubt on that. In any case, the oxygen boost is a plus, also helping pave the way for possible early pressing.
Pressing, Aging and Blending
The Cabernet should be pressed as soon as it reaches dryness, measured by a hydrometer. The Syrah, on the other hand, should probably be pressed slightly early, between 2–5 ºBrix, and allowed to finish fermentation in carboys (or barrels) with airlocks. The same logic again: get all the structure you can from the Cab, get the fruit and dodge the tannins and any late over-extraction from the Syrah.
Since this is a planned blend, the sooner the parts get together, the better—the better for settling the overall wine chemistry, and the better for being able to taste and smell what’s in the pipeline as a whole wine. And all of the wine, separately or together, needs to get inoculated for a malolactic fermentation (MLF) right after fermentation. The sooner the malolactic starts, the sooner it finishes, and the sooner you can do a major sulfur dioxide addition to protect the wine from spoilage.
My approach here has been to press each wine into carboys, inoculate with malolactic starter bacteria, let everything settle a few days so the gross sludge can hit bottom, and then rack a draft blend into barrel. Starting with a 50:50 blend is fine, with a small amount of each wine reserved for tweaking and topping over time. If you are doing this on a carboy scale, it still helps to rack the wine off the gross lees before combining.
You can choose to make the blend later on, when both wines have developed a bit more. This can sometimes offer more control of the blending proportions, based on blending trials, but gives the wine less time to come together and perhaps less time in barrel.
Here’s the place to explain how I got into this almost by accident. From the 2006 harvest, I had a couple gallons of Cabernet left over from a Bordeaux blend, and I always have some Syrah around on general principle. Late in the game, I put them together in a carboy, tossed in some oak cubes, more or less forgot about it — and ended up with two cases of very tasty wine. Which inspired me to do the project on purpose in 2008, filling a 30-gallon (113-L) barrel with 15 gallons (57 L) of each, from the same grape sources as the 2006 trial balloon.
A month or two after composing the draft blend, test for malolactic completion, as well as for pH and total acidity. Make any necessary acid adjustments, and hit the blend with SO2 at a level corresponding to the wine’s post-processing pH.
Cab-Shiraz blends benefit from moderate amounts of oak, whether from cubes or barrels. You don’t want to make a lumber-driven wine, but the density of these two grapes can soak up some oak flavors without getting lost in them. A one-year-old barrel is just about right, or an older, more neutral barrel with some chips added. French oak is gentler, American oak more forward, and both are fine for this wine. In the carboy version, try 4.0 ounces (113 g) of cubes in a 5.0-gallon (19-L) container for two or three months, and then refresh the oak at racking time if a bit more oak seems appropriate.
Finally, this blend is a good candidate for bâtonnage, lees stirring. Stirring lees once a week in barrels or carboys for several months helps promote autolysis of the spent yeast, adding especially textural compounds to the developing wine. Mouthfeel can also be enhanced by adding various yeast-derived preparations and packaged tannin, but unless your lees are of the stinky persuasion, which have to be removed from the wine, stirring your own is a much simpler way to go.
Taste the wine as it develops. Look out for emerging faults — volatile acidity, reductive aromas — and deal with those problems promptly. See how the balance of acid, oak, tannin, alcohol and fruit is coming along and adjust things as needed. After a few months, if it’s clear the blend needs some more Cab or some more Syrah, and you have some available, blend it in. If the blend still seems too roughly tannic, which is unlikely, consider a light fining to smooth the rough edges.
After a few months, the logic of this blend should start showing through — a softer and more accessible wine than most Cabernets in their youth, more “grown up” than many New World Syrahs tend to be early on. All of this the result of less than two weeks of properly handled fermentation. If your wine is maturing in small vessels, it should be ready to bottle a year from harvest. Light (5 micron) filtration will help give a clearer, more brilliant wine. Use standard bottling procedures — careful sanitation, a light final SO2 addition (25 ppm), and a fanciful “critter” on your label to carry on the Australian theme.
And then try and keep yourself and your friends from drinking all of it before it has a chance to age.
Tim Patterson is a frequent contributor to WineMaker magazine.
- Egg White Fining, Overoaking: Wine Wizard
The Wizard explains the intricacies of egg white fining. Plus: why an overoaked wine needs blending.
Using egg whites
I’m making a white wine and want to add egg white to help with the fining before my last racking. Is there any information on how to do the egg white thing?
Colorado Springs, Colorado
For readers who don’t know, adding a solution of egg whites to wine does a nice job of pulling out excess tannins and phenolics that might cause your wine to be overly astringent and/or bitter. Traditionally used in Burgundy as a way to “smooth out” the rough edges that might exist around one’s Pinot Noir (horrors!), egg white fining has a big fan club around the globe because it’s an all-natural, minimally-interventionist way to polish up one’s red or white wine before bottling.
The big question you have to ask yourself is: how tannic is your wine, really? Since you’ve got a white, I’m guessing not too bad unless you squeezed the snot out of it at harvest-time. It is red wines that typically need higher doses of egg whites because they naturally carry more tannin — the more egg white you add, the more tannin the protein will pull out of solution. A not-so-tannic wine that needs just a teeny bit of smoothing out probably will do well at a dose of 0.20 mL of egg white per gallon of wine while a red wine with perceptible pucker and astringency may do better at 1.0 mL of egg white per gallon dose. If you have the patience (and the ability to measure out really small volumes) try doing a “bench trial” on 100 mL of wine or so first, to see what you prefer.
However, if you want to just go with a gut feeling, that’s OK. Figure that your average American egg will have around 24 mL of egg white per shell.
For 20 gallons (76 L) of wine, here’s my egg white fining procedure (multiply the quantities accordingly):
1. Break your egg and carefully separate the white from the yolk.
2. Measure out 9.2 mL of egg white in a graduated cylinder or with a pipette and place in a small bowl.
3. Add a tiny pinch of table salt and enough water (a few mL or a little more) to make a liquid solution.
4. With a whisk or a fork, gently dissolve the egg white into the water, taking care not to beat too much air into the solution. We don’t want any meringues here!
5. Dump the entire solution into your vessel and stir gently with a long stirring rod for about 30 seconds or so to make sure the liquid is distributed.
6. Leave covered (if you have headspace, gassing with CO2 or Argon is always a good idea after you open a vessel) for about two-three weeks to settle out.
7. Rack the wine carefully into another container (that hopefully is a good fit for your wine volume — we want everything topped up, right?), leaving any sediment on the bottom.
Feel free to leave the wine sitting a little bit longer until you rack in case you can’t get around to it, but don’t wait longer than four weeks. I’ve sometimes had wine sitting on egg white fining for too long get “manky” (a term my Australian interns used to say, I think it means “gross”).
Too much oak
I used oak in one of my trials of Minnesota Marquette wine. My trial was 5 gallons (19 L). Is there a way to filter off some of the oak taste?
I’m so pleased you’ve done some oak trials! If you’ve read my column over the years you know that I’m always advising our intrepid readers to do small-scale trials (sometimes I call them “bench trials” after the “lab bench” work surface of your average
winery enologist) before they commit to an additive or course of action for their precious gallons.
It sounds like you found a trial result that you weren’t too keen on, i.e. too much oak added to one of your carboys. I’m glad (and you should be too) that you only treated 5 gallons (19 L) of your wine; if you had done that oak treatment on a whole barrel (or more) you’d be dealing with a lot more unpleasant wine! Unfortunately, once we’ve added oak to a wine and it’s absorbed into the wine (whether via a barrel or oak beans, chips or segments), there’s no getting rid of it. The oak aromas, flavors and even a small amount of tannins and phenolic compounds have now become, for better or worse, intrinsically intertwined with the aromas, taste and mouthfeel of your Minnesota Marquette.
What can you do? The only realistic option is to blend your 5 gallons (19 L) with something else that would dilute the oaky aroma and flavor. Not knowing what extra gallons (liters) you have sitting around in your cellar, however, it’s hard for me to know how to advise you toward that end. However, you can do what many wineries do and keep those 5 gallons (19 L) as an “oak blender,” i.e dose small amounts of that wine into other lots as a flavor/aroma adjuster. That way, over time, you’ll eventually use up the over-oaked wine and you’ve made some of your other lots presumably better. As a last resort, if you don’t have any wine you can add to the 5-gallon (19-L) lot and if you can’t “disappear” those 5 gallons (19 L) over time into other things, you can do it the old fashioned way and just . . . wait.
Though once oak is in wine it tends to stick, the aromas and flavors will change and develop over time to a certain extent. Sometimes the change can be positive, i.e. sometimes the aromas will mellow out a little bit and change from being obviously oaky to seem more integrated. This last-ditch approach works best for wine lots that aren’t hideously over-oaked to begin with. At the very least, you’ve done something all good winemakers the world over do: you’ve learned what does not work for your wine, which is just as valuable as learning what does.
UC-Davis graduate and professional winemaker Alison Crowe has been answering hundreds of your winemaking questions as the “Wine Wizard” since 1998. She is the Winemaker for Plata Wine Partners, LLC, and provides custom winemaking services and consulting to nationally distributed as well as small start-up brands. Her columns are collected in The Winemaker’s Answer Book, available at www.winemakermag.com/store. Do you have a question? Send your inquiries to her at: firstname.lastname@example.org.
- Cold Soaking: Tips from the Pros
Two pros give tips on coaxing more color from your lighter reds via cold soaking.
Melissa Burr, Winemaker at Stoller Vineyards in Dayton, Oregon. Melissa was raised in the Willamette Valley and, after completing her BS degree, studied winemaking at Chemeketa Community College in Salem, Oregon, and fermentation science at Oregon State University. She came to Stoller in 2003 after working as a harvest hand at several local wineries. She has been the production winemaker at Cooper Mountain for three harvests.
The grapes at Stoller Vineyards that we cold soak are Pinot Noir. I like using this technique to build the richness and flavor of the juice so that when fermentation starts the wine has had a head start on extraction.
In our particular winery, we benefit by cold soaking the grapes as it also encourages/allows time for the native or indigenous yeast in our winery to get established for fermentation. I really like the complexity and nuances that our indigenous yeast contributes to our wines.
In addition to the advantages for the character of the wines, cold soaking also has some practical advantages; mostly that after three days you get a more accurate measurement of the sugar content and chemistry of the must.
For home winemakers, it is a good idea to experiment with cold soaking if you haven’t tried it in your own winery to make your own winemaking decisions. For example, I have done experiments with cold soaks, such as cold soaking part of a batch for longer and then the other portion shorter. Through these time-based experiments I have found that I tend to prefer the longer cold soaked lots.
Any winemaker, whether you are making small batches at home on up to the commercial scale, can benefit from experimenting with cold soaking certain grapes. I would say that the biggest benefit is ultimately by building the flavor of the juice and attaining extraction ahead of time to make richer wine.
The risk, however, is contamination by spoilage organisms, so I would caution to make sure that there has been some SO2 added to the must before the cold soak starts to knock back any bad guys trying to get in. I add 50 ppm to all my grapes as I destem them prior to cold soak if they look good and clean, and 75 ppm SO2 if they have botrytis.
Chaim Gur-Arieh, Founder and Winemaker of C.G. Di Arie Vineyard and Winery in Mount Aukum, California. Chaim holds a master’s degree in food science from the University of Illinois in Urbana. He worked with the Quaker Oats Co. in Barrington, Illinois, where he developed the technology for the breakfast cereal “Cap’n Crunch”®. In 1998 Chaim and his wife Elisheva sold their company, Food Development Corporation, a company specializing in food product development, to purchase 209 acres in El Dorado County where they built their gravity-feed winery and developed 40 acres of vineyards.
At C.G. Di Arie, we cold soak all of our red varietal wines and the process begins at harvest. Cold soaking gives the grapes a gentler crush and introduces less harshness into the wine.
Following harvest, for cold soaking, I set the crusher to just barely bruise the fruit. At this point, depending on the temperature of the incoming fruit, we add dry ice to the crushed grapes while they are being conveyed into the tank to drop the temperature to 55 to 60 °F (13 to 16 °C). We also add sulfites to discourage any undesirable microbial activity.
Since we are crushing so gently, we don’t have enough juice to be able to start the fermentation right away. We maintain a temperature of 55 to 60 °F (13 to 16 °C) for a sufficient amount of time until enough juice is created. This could take two or three days from the day that the fruit goes through the crusher.
During this time the pectin enzymes in the fruit is liberated during the crushing act to break down the pectin and thus releasing the juice from the cells. This also liberates or creates some other aroma compounds that enhances the flavor of the finished wine.
Without the cold soak there would be a chance to start the fermentation pre-maturely prior to my inoculation. Also, the cold soaking enables the pectolytic enzymes to become active introducing into the wine desirable attributes.
- Can I Reduce Tannins in a Wine Kit Without Aging?
I seem to have extracted too much tannin during primary fermentation of my Cellar Craft Carmenère kit because the must is quite tannic and bitter. This is probably because instead of just punching down, I also squeezed the bag containing the grape solids (grape pack that accompanied the wine kit) once/day. I did this with a large stirring spoon, squeezing the bag repeatedly against the inside of the primary pail. This wine is currently in secondary fermentation, but I’m wondering if there is anything I can do to reduce the tannins short of waiting for several years for it to hopefully mellow out. Is there anything you can recommend to reduce the tannins of this current batch to a reasonable level?
It seems to me like your Carmenère is a candidate for one of the “Wine Wizard’s” cheapest, easiest and most favorite ways to improve a tannic wine; egg white fining! What could be simpler (or more traditional) than grabbing an egg or two from the fridge. Egg whites are mostly made up of a pure protein called albumen, which has been used by winemakers for centuries to clarify, settle and lessen the tannin content in their wines. Depending on how much you add, the egg whites will cling to an increasingly large amount of the bitter and tannic elements in your wine and, as the protein molecules stick together and get bigger, they will eventually become so heavy as to fall to the bottom of your carboy, barrel or tank, effectively forming a layer of sediment at the bottom off of which you can rack the cleaned-up and less-tannic wine.
Sometimes wines just need a little bit of added egg white to get the desired effect, say like a Pinot Noir. Heavier reds tend to need a heavier hand, and Carmenère can sometimes be a beast. I’ve had lighter-style Carmenères but it sounds like you’ve got one with significant tannin. Since I don’t know how large your kit size is (the Cellar Craft website says they range from 7.5-16 L) and can’t taste your wine, all I can give you is an approximate range of addition. As a reader of my column, you know I’m a proponent of people doing bench trials first, that is, treat a small amount (say 1L or even 100 mLs) of their wine first with a proportionately small amount of their desired additive. This way you can fine-tune the amount of an additive you want to introduce to get the desired effect but without over-doing it.
My guess is that you’re going to want to add around 5 mLs egg white per liter or so of wine, since you do seem to have some pretty tannic wine. It doesn’t hurt to start there. You can always add more if you need to, that’s the beauty of egg white fining. If you have 100 mL graduated cylinders and some small pipets (little tubes with measured graduation on the side, which allow you to suck up and dispense small amounts, even fractions of a millileter of liquid) you could even do bench trials in 100 mL sizes, and try 0.5 mLs per 100 mL of wine. Then try more and possibly less to see if you like a better effect. Whether you do a bench trial first or just choose to treat the whole lot, here’s the basic procedure:
•Carefully break your egg open and separate the yolk from the white. Save the yolks for something else, perhaps crème brûlée?
•Measure out the desired amount of egg white. Add a pinch of table salt per egg white used. If the egg is too viscous or difficult to measure, sometimes I agitate them gently with a fork first, without aerating, to break up the ropy proteins. The idea is to distribute the egg white, not to create a foam.
•For every egg white used, add about 2–3 mLs of water to help further “liquefy” the egg white and form it into a solution you can measure.
•Measure this solution (taking into account how much water you added) and add the desired amount (if you’re doing bench trials, use your pipets here) to your wine.
•Gently stir the wine with the egg white solution added, for about 1–5 minutes or until you feel the container has received a good mix. A 100 mL bench trial would take about 20 seconds whereas a barrel would take about three minutes with a big barrel-stirring wand (the kind with a blade on the bottom).
•Cover up or bung up your container of wine and let the egg whites do their thing; they will naturally glom on to the tannins and bitter phenolics and will form a layer of fluffy solids at the bottom of your container.
•After about two weeks, carefully rack your clarified wine off of this layer and voila! You can always taste a sample from the top of the container after about a week of settling to check if you think you’ve added enough egg white. If not, dose the container again with some additional egg white, stir and let settle out again until you are happy.
Other proteins to try (which remove tannins and bitterness) include products that contain gelatin, isinglass or casein (milk protein). There are lots of different commercial preparations available to winemakers online or in their local home brewing shops, but since I always have eggs around the house I tend to head there first.
- Award-Winning Red Winemakers Roundtable
Award-winning winemakers give their tips for making reds.
What does it take to make world-class wine at home? Over the years since WineMaker started hosting the WineMaker International Amateur Wine Competition, many readers have written in asking variations on that same question. Is it the fruit? Is it the winemaker? Is there some sort of magic yeast strain or enzyme that might make a so-so wine into something gold-medal worthy? There are no magic tricks to making better wine, but there are certainly some ways that you can improve your wines. So how do you make wines that win medals? You ask the experts, of course! We persuaded three of the WineMaker competition’s frequent medal winners to share some of their award-winning secrets for making red wines.
Dan Boykin, Concord, California
2010: Gold in Cabernet Sauvignon, Gold in Zinfandel, Gold in Malbec,
2 Bronze in Bordeaux Style Blends
2011: Gold in Shiraz/Syrah, Bronze in Zinfandel, Gold and Silver in Other Red Vinifera, Bronze in Red Vinifera Bordeaux Style. 2 Gold and a Bronze in Port Style
Rex Johnston, Walnut Creek, California
2010: Winemaker of the Year, multiple Best of Show winner over the years
2011: Winemaker of the Year, Best of Show Dessert,
Bronze in Zinfandel, Gold in Port Style
Jason Phelps, Londonderry, New Hampshire
2010: Gold and Bronze in Bordeaux Style Blends,
Bronze in Cabernet Sauvignon
2011: Bronze in Port Style
What kinds of red wines do you make and how?
I make the classic five Bordeaux varietals: Cabernet Sauvignon, Cabernet Franc, Merlot, Malbec and Petit Verdot from fresh grapes or frozen must.
I stick to the book as far as yeast rehydration, feeding, etc. Treat the yeast well they will make great wine.
I make six reds (when I make reds), but I don’t make the same reds every year. I make Cabernet Sauvignon, Cabernet Franc, Merlot, Petit Verdot, Malbec and Red Meritage. I also make six whites: Sauvignon Blanc, Sémillon, Gewürztraminer, Viognier, Chardonnay and White Meritage, as well as ten to twenty fruit and dessert wines which vary from year to year.
I make Merlot, Amarone, Cabernet, Pinot Noir, Rhône Blends, Malbec and Syrah. I make them from kits, fresh grapes and fresh juice, depending on the varietal and availability.
I make small batches of about 1–6 gallons (3.8–23 L) each, as well as many small 1–3 gallon (3.8–11 L) experiments — all with simple winemaking equipment in my kitchen.
How many wines do you normally make in a year?
I make a large batch of each of the five varietals I listed earlier, plus Syrah, Petite Sirah and Zinfandel. I also make a Port (or two or three) from some of the above. Last year I made the rosés from saignée into Ports. In fact, the Petite Sirah Rosé Port is one of my best wines ever — and it was an experiment!
Fifteen to twenty five.
Overall I make roughly ten to twelve styles that can range in volume from ultra-small batches to 6–12-gallon (23–45-L) size batches.
For reds, I make three to six batches, and I expect to make about that many again this year.
For fresh fruit winemakers, where do you source your fruit, and why?
I make all from grapes (frozen must or fresh, just depends on the circumstances or time of the year).
I did make one Port from frozen blueberries, frozen made it easy to extract all the flavor and other good stuff without actually crushing them.
I get plums and apples from my backyard, berries and plums, etc., from the farmer’s market, and things like rhubarb, mangos and strawberries from the grocery store.
I buy most of my fresh winegrapes from M&M Wine Grape Co. (out of Hartford, Connecticut). I also get juice, must, and frozen crushed grapes from them, but also from other sources as well. I should note that I have only two years of experience making wine with grapes.
For kit winemakers, explain how you choose the best wine kits?
I simply choose higher-end kits, often aromatic whites.
I most often buy kits based on recommendations from people who have made them. I like to choose niche styles that are hard to get in fresh fruit form.
Choosing wine kits based on past medal winners is a good guide.
How many wines did you enter in this year’s competition? How frequently do you enter your wines in competitions?
I entered 12 wines in the 2011 competition and was surprised with one of the wines I just entered only because I had an extra space in the shipper — it got a gold! I enter four competitions every year, and I try to get every wine into all four, that way I get feedback and pick up the various nuances of each set of judges. I have found remarkable consistency in individual competitions, but amazing variety between each. One got double gold in one and Bronze in another. But when I get gold or silver from several I know I hit a good wine.
I entered 15 entries in this year’s competition, and I typically enter around 4 to 7 competitions each year.
I entered ten wines in this year’s competition, and I tend to enter only one or two competitions per year. I love the feedback that comes from the judging notes, because it helps me to train my own perceptions.
How do you select and prepare the wines that you enter in competition — for example, do you randomly select bottles from a batch?
I just grab one from the case. I have started keeping permanent labels off a few (just stick an easily removed temporary label on it) when bottling, which makes it easier at entry time.
I check each for sediment, clarity and leakage before packaging them for shipping.
I taste, taste, taste. I look for wines with high clarity, good balance and solid aromas (in addition to great taste).
Typicity (the degree to which the wine reflects its varietal origins) is also a consideration, sometimes it is even the deciding factor in deciding what to enter.
When you make your wines, what kinds of techniques do you use to benefit the style of wine you are making?
I again stick to the classic advice: if I want a big red with high alcohol, I add sugar or pick with high Brix. I always saignée, and am experimenting with different levels. If I want as much extraction as possible, I cold soak using dry ice. If I want it light I will press early. I have done extended maceration with good success too.
I like to use enzymes for macerating, pectolytic and aroma releasing.
My best technique for making better wines is to constantly taste. I taste many, many wines — good ones and bad ones — and use that knowledge to assess integration and balance in wines.
Knowing the wine’s style really helps you to make that style yourself. It is also good to know about multiple regions and styles for blends and more specific regions for special sourcings.
Do you do anything when winemaking that would be considered out of the norm for straightforward winemaking?
Yep. I add oxygen (via a tank and aeration stone) directly in the ferment after punch down once a day for the first three days max, for about two minutes.
The yeast needs lots of things but two are critical: nitrogen — thus test that yeast available nitrogen (YAN) — and oxygen (O2).
I always perform a cold fermentation for my fruit wines with bayanus yeasts.
I work in small batches, so I don’t typically do anything out of the ordinary for my red wines. I do like to experiment with grape and fruit blends, however. For example, last year my wife asked to make a Blackberry/Cabernet, which was very successful. We amped up some Cabernet juice with wild berries, sugar and tannin and fermented it almost dry. It really is fantastic and has medaled twice so far. One more medal and it will be our most successful single batch.
What are some winemaking products (such as enzymes, additives, fining agents) that you like to use, and why?
Fermaid, GoFerm, DAP, ACTI-ML and OPTI MALO®. All of these keep the little yeast or ML bacteria well fed and happy. When you go to work you like to be happy, so keep these workers happy, they will do good work!
Novarom Blanc, Xtraoak Zoakers.
I learned about enzymes at last year’s WineMaker Magazine Conference (in 2010) and have used Opti-Red and Opti-White for all of my wine since then. I have experienced better color, aroma and flavor across a range of different wines.
I also re-hydrate my yeast with Go-
Ferm and feed with Fermaid-K. Fermentation progress has been steady and successful.
What, if any, fining and filtering do you perform on your wines?
I rarely fine or filter as most of the reds settle right out.
I read up, however, if I have a problem, like bitter taste, on what to use — Daniel Pambianchi’s home winemaking book is a great reference!
For whites, I like to use bentonite. For reds, I fine with egg whites. I don’t fine the fruit wines. I sterile filter all of
I fine with bentonite, isinglass and chitosan, based on both kit ingredients and selections for different fresh fruit batches. Allowing for considerable settling a careful racking and light fining with bentonite is my preferred method. I do not own a filter and use a simple auto-siphon to carefully rack from one container to another.
What yeast strains do you prefer? What did you use for the winning wines?
I always use three yeast strains with almost every wine I make — as separate batches — then blend after primary fermentation is over. I like MT, BM45 and CLOS for the Bordeaux, an occasional D80 for Merlot. For Syrah I use MT, D254 and GRE. For Zin and Petite Sirah I might choose AMH, SYR or GRE and MT. I try different combinations each year. I find D254 has great mouthfeel, and MT adds structure.
I cannot recommend trying differing yeasts at least once strongly enough. Keep them separated through MLF, and use the same ML bacteria on both. Try D254 and Clos with a Bordeaux varietal, keep them separate then taste as you press (of course after ML is complete). I guarantee even a novice wine lover will taste the difference. Both will be great, just different. (I personally love both!) Then line them up and mix equal parts of each in one sample — you are in for a real treat, the combo of both will be better than either of the two!
If you blend three, you get more flavor combos to try!
For reds, I use Pasteur Red; for whites and fruit wines I use a bayanus strain.
I have used several types of yeasts, including Bordeaux style, Rhône style, EC-1118 and Premier Cuvée. I haven’t gotten enough good feedback from my 2010 wines to be sure what to conclude from some of the new products I have experimented with, however.
How long do you usually age your wines before entering them in competition, and why?
Have you been talking to my lovely wife Marianne (also known as the royal official taste tester at Tuba Cellars)? She constantly tells me to be patient, but I enter after about four months.
But, I learned a real lesson this year: I entered a Malbec early, then into each competition as it came up, it got progressively better, and by the end it won double gold.
So you have to wait. (I will try!) I have learned to at least wait on the Cabs for a year or so after bottling. Yes Marianne, you were right!
For my reds, I like to age anywhere from two to six years.
For whites and fruit wines, none — the younger they are the better.
I typically age anywhere from six to twelve months, depending on how it came out. Sometimes I enter a wine into competition earlier than that if I have a suspicion that they might not develop any further. Some wines have aged longer, but I don’t make enough to keep it around all that long — and I usually drink most of it.
What other advice could you give for making wine that we haven’t covered?
Try SIY (specially inactivated yeasts) as a post fermentation (during aging) additive. Do a trial, of course. I have been experimenting more and more with Booster Rouge and Noblesse (small amounts are easily available to buy on the Internet). What I do is try these at the rate of 3, 6 and 9 grams per hL (100 liters) by adding 3.8 grams to a 375 mL bottle of distilled water.
Then I prepare 375 mL bottles of the wine for the trials. If you add 1.125 mL of the solution per bottle it equals 3 grams per 100 liters (it seems like a tiny amount, but trust me you will see an impact). I do this at the rates above, then cork them and agitate them (including a control bottle with nothing in it) once a day for a week, preferably two. (This stuff does not dissolve in water and needs a little encouragement in wine so agitate the distilled solution before each trial addition as well.)
Then have some friends over and taste the wine — you will taste the difference and it really can improve the wine. I do the math and add it to the wine, let it sit for at least a few weeks then bottle. Oh, and feel free to mix the two product trials as well (Booster and Noblesse). You will be surprised.
In my day job I am a banker, so I have learned the risk of “having all your eggs in one basket.” So I believe it is best to make several batches of wine in small amounts. I find some are good and some just don’t cut it.
I have great admiration for all the guys and gals I meet each year at the WineMaker Magazine Conference who make one ton of one varietal — but what if it is awful? I just can’t sleep knowing that I have only one shot at a good wine when I know that for myself that some come out great and some are just so-so. Plus, your friends really have a great time barrel tasting.
Always try something new. Last year I made a Merlot Port because Janice (my grower) had made one and I was intrigued.
This year I plan on a Petit Verdot Port. I have no idea what it will be like, but why not give it a try? The Merlot Port is awesome — I wish I had made more.
Lastly, did you teach yourself how to golf, or play the piano, or knit or whatever else you like to do? Probably not, and when that tutor or mentor showed you one little thing it made the experience so much more satisfying. So find a winemaking tutor. Go to the boot camps, classes or seminars in your area, and find a winemaker you respect and ask for feedback, advice and help. Be willing to compensate them for their time. (You have skills you get paid for, so do these people.) I live in California so there are hundreds of possibilities, but I found Shea Comfort (frequent contributor and speaker for WineMaker, and darn near in my backyard). He showed me once in 2007 how to balance the must and now I know what to do. Get a tutor — it is really okay and will save a lot of frustration!
The most important advice, which I have only learned myself in the last year, is the use of gum arabic — specifically, purified gum arabic from the seyal tree. This product has several benefits. The foremost improvement in winemaking is the elimination of cold temperature stabilization of white wine. Other advantages, which I had become aware of earlier, are red wine color stabilization, white wine aroma enhancement, and bubble persistence in sparkling wines.
Finally, gum arabic improves the mouthfeel of all wines.
Always look for new styles of wine to try to develop your knowledge of how wine is supposed to taste.
Take note of new aromas, flavors and textures that are waiting in each new glass. And of course, keep things clean — keep your all of your equipment scrupulously clean and sanitized.
Betsy Parks is a graduate of the New England Culinary Institute, Associate Editor of WineMaker magazine and author of the “Tips from the Pros” column.
- Adding Sugar to your Must
It's not uncommon to find yourself working with fruit that doesn't have enough natural sugar. Learn about adding sugar to must for boosting potential alcohol and stability.
- Cold Soaking Success
Consider performing a cold soak to extract the most color from fickle grapes.
If you have ever researched how to make Pinot Noir, you have no doubt come across the term “pre-fermentation cold maceration” or simply “cold soak.” Although a cold soak is used on other grape varietals, lowering the temperatures prior to fermentation is primarily done to coax more color out of Pinot Noir, which tends to be a bit color shy.
Cold soaking has its followers and detractors, however. One camp of winemakers believe that wines made utilizing a cold soak are more complex and fruit-forward, and exhibit improved color retention. By soaking their grapes at lowered temperatures for a period of time, they can extract anthocyanins (color), aromatics, supple tannins, improved mouthfeel, and flavor compounds more effectively than is thought to be possible with conventional methods. The opposing camp of winemakers feel that this whole process is not necessary and does nothing but increase the possibility of spoilage, and produce short-lived effects that don’t last long enough to make it into the bottle. These winemakers prefer to use maceration enzymes, pump-overs, heat, and alcohol to get their desired result. While there is little scientific data and few studies to look to supporting the efficacy of the cold soak, it seems to be an artistic winemaking decision rather than a process soaked in facts. Whether or not you believe it helps, cold soaking is perfect for small batch experimentation in a home winemaking setting. The primary focus of the technique for this article will be red grapes, although wines made from more aromatic white grapes can certainly benefit from a short cold soak prior to fermentation. This can increase aromatics from the grape skins along with some desirable flavor compounds. These compounds help contribute to the body and aging potential of the wine.
Temperature & Duration
The most important factor in performing a cold soak is maintaining a temperature from 40–50 °F (5–15 °C). This is primarily a function of microbial spoilage prevention for the duration of the cold soak. Without the protection of lowered temperatures, lengthy pre-fermentation maceration at ambient temperatures would promote oxidation and microbial spoilage or carbon dioxide produced during fermentation.
The average cold soak is conducted for about four days, although some winemakers are known to push it to the limits and macerate for seven to fourteen days. It is difficult to provide a one-size-fits-all time when first attempting a cold soak, so keep your time intervals short until you gain experience in maintaining low must temperatures. This will prevent any spontaneous fermentations or spoilage. In home winemaking things are rarely perfect, glycol jacketed tanks may be available but aren’t the norm, and we use what we can to reduce the temperatures of the must. In his book Techniques in Home Winemaking, Daniel Pambianchi recommends freezing water in freezer bags or plastic milk jugs (ice bombs) that can be added to the must to bring the temperature down. Be sure to sanitize the ice bombs prior to adding as not to contribute microbial spoilage organisms. Pay close attention to keeping the temperatures at the desired level. This involves rotating ice in and out as needed, stirring the must twice daily, (stirring evenly distributes the temperature throughout the primary fermenter, and prevents microbes from setting up shop on the surface). Check the temperature every time the must is stirred, which will avoid opening the primary fermenter more than is needed, especially when using inert gas.
Other Benefits of a Cold Soak
Besides retaining color, there are other possible benefits to cold soaking. First, the must has time to soak and get thoroughly mixed. This helps to reveal more trustworthy readings of base chemistry such as Brix, titratable acidity, and pH. This is especially true for Zinfandel grapes that often come in very ripe with raisined grapes. Through soaking, these raisined grapes can release sugars over time, giving a better picture of the potential alcohol of the must.
By locking the color in early in the process, you have the option to press early, which avoids extracting harsh alcohol soluble-tannin from the seeds and stems later in the fermentation. This allows the decision to press to be guided by taste rather than the numbers.
How to Cold Soak
I have devised a comprehensive list of steps to do a cold soak at home. Carefully review the steps prior to receiving your grapes so you are prepared.
The use of ice bombs to maintain proper temperatures during a cold soak is intended for winemakers using 20- to 40-gallon (75- to 150-L) food-grade plastic trash cans as primary fermenters. Due to their size, half-ton macro bins will need dry ice to keep them cool. Dry ice gets down to -109 °F (-79 °C), and you will need to follow strict safety standards when handling — including using gloves, and using it in an open space. Be sure to use food-grade dry ice. Use dry ice at a rate of 100 lbs./ton of grapes or 0.8 oz./lb. (50 g/KG.)
1. Depending on the batch size, you may need to use up to five 1-gallon (3.8-L) jugs of ice at a time, with back-up jugs to be rotated as the others thaw out. Start saving plastic jugs and freezing them well in advance of harvest and crush. Otherwise, buy a box of heavy-duty freezer bags.
2. Prior to crush, Daniel Pambianchi recommends an additional step of cooling the grapes prior to processing. This can be done by placing dry ice on the harvested grapes, purchasing them already refrigerated, or harvesting at night or early in the morning while the grapes are still cool. This will facilitate the cooling process and minimize oxidation during crush. If none of these recommendations are possible due to transportation logistics or your harvest schedule, just do your best and have sulfite and ice bombs ready to immediately start the cooling process.
3. Crush and process your grapes in the usual fashion into your primary fermenter.
4. The must is kept cool enough to slow most oxidative or microbial processes down, but without the use of sulfite, the risk of spoilage is increased significantly. If you choose to use sulfite, add it to the wine at a rate of 25–50 ppm.
5. Add your ice bombs or dry ice. For comparison, I am able to keep 20 gallons (75 L) of must at 45 °F (7°C) with three ice bombs.
6. Although it is safer to allow the must to warm up after cold soaking prior to yeast inoculation in a home winery setting, Thomas Henick-King, Professor of Enology at Washington State University, suggests making a yeast starter and adding it prior to cold soaking. The yeast slurry should be carefully adjusted to the must at ambient temperature and added to the must prior to cooling. Acclimating the yeast to the must temperature is a very important step so as not to shock the yeast cells. The addition of a yeast starter culture will suppress the growth of unwanted yeast and bacteria during the cold soaking.
7. Keep your fermenter tightly sealed. I have found in the case of food-grade plastic trash cans a beach towel over the top in combination with snapping the lid down does a great job of keeping out fruit flies and containing the inert gas.
8. If you are uneasy about leaving your must to the open air within the fermenter, in his book Home Winemaking Step by Step, Jon Iverson suggests you lay plastic wrap across the must to minimize oxygen exposure (for food-grade plastic trash can fermenters). Another option is to flood the headspace of the fermenter with argon or carbon dioxide and effectively blanket the must. This would of course need to be repeated every time you stir the must to ensure an adequate protection is achieved.
9. Replace ice bombs as needed and closely monitor the must temperature twice daily as you punch the cap and stir up the must. Be sure to taste the juice often to detect any possible off flavors forming. If you see or smell signs of fermentation, it is time to remove the ice bombs, allow the temperature in the fermenter to rise, add your yeast and nutrients, and get fermentation into high gear; this will prevent wild yeast from getting too much of a foot hold. If you inoculated prior to cooling the must, allow the temperature to rise and allow fermentation to proceed.
10. Once you are satisfied with the cold soaking period, simply remove the ice bombs or any remaining dry ice blocks and allow the must to reach ambient temperatures for fermentation to finally commence. Then add your yeast starter if you did not do so prior to the cold soak. In the case of white wines, the must will then be pressed and inoculated with yeast.
Not all grapes are good candidates for cold soaking. Low quality or damaged fruit will harbor even more bacteria and unfriendly yeasts than unbroken grapes normally would, making the process riskier. Because of this, it is best to only perform cold soaking with sound, fully ripened fruit. Also, if you are not able to dedicate the time to pay special attention to temperature control, forgo cold soaking
While cold soaking is debated in winemaking, and despite few studies being done on the subject, this shouldn’t keep you from giving the technique a try. Creativity and artistic experimentation, after all, is part of the fun of making wine, and is what leads to interesting wines.