Fermentation & Cellar - Common Questions

For standard primary fermentation inoculation, we recommend an addition rate of 2 lb/1000 gal (25 g/hL) of total juice to achieve a stable and effective population. For high Brix (greater than 25 °B) juices, increase the inoculation rate to 2.8 lb/1000 gal (35 g/hL). To restart a stuck/sluggish fermentation, refer to Scott Labs Recommended Method to Restart Stuck Fermentations.

Please refer to the yeast rehydration guides below:
Easy Steps for Optimal Yeast Rehydration of Lallemand Yeast
Easy Steps for Optimal Yeast Rehydration of Anchor Yeast

To restart a stuck/sluggish fermentation, please refer to Scott Labs Recommended Method to Restart Stuck Fermentations

Select yeast based on the grape and style of wine you would like to create. You should also consider your fermentation conditions (e.g. temperature, high BRIX, etc.) and must nutrient levels (YANC). Select the best strain that can tolerate and thrive in your must/juice condition and still deliver the sensory characteristics you desire. For more information about our available strains, please refer to our yeast section.

The top yeast strains for fruit wine fermentation are K1 (V1116), EC1118, DV10, 71B, D47, M2, VIN 13, QA23 R2, and W15. For cider fermentation, the top strains are DV10, EC1118, K1 (V1116), M2, Opale, QA23, R2, and VIN 13.

Some yeast strains are able to metabolize malic acid at greater rates than others. VRB and 71B are yeast strains that have been observed to reduce malic levels.

Killer yeast contains a toxin in their cell wall structure that allows them to kill toxin sensitive foreign yeast cells. Most killer strains of S. Cerevisiae have good fermentation kinetics, and therefore have a greater chance of dominating the fermentation. If indigenous yeast is perceived as a potential problem, strains with this factor may be beneficial. Our various yeast strains can exhibit, be sensitive to, or have a neutral reaction to this factor.

Each yeast strain has a temperature range in which it is most active or sensitive. For specific yeast temperature requirements, please refer to the individual product descriptions.

A good yeast selection for a wine with a high fructose fraction is ICV-KI (V1116). ICV-K1 is fructophilic and a vigorous fermenter. This strain exhibits a killer factor that is helpful when indigenous yeast is still present.

The first yeast strain used may not have acclimated to a difficult condition of the wine or was inoculated with a low population. It is often better to chose a strain better adapted for high alcohol, high SO2, or a competitive atmosphere. Using the same strain may or may not work the second time. Make sure to carefully follow a recommended restart protocol.

A dried yeast culture will begin to absorb moisture as soon as it is opened. This can trigger the yeast to reactivate. If no must or nutrients are available, the yeast dies or becomes weakened. An open container also becomes a rich media for possible microbiological growth. It is recommended to close the container tightly immediately after opening. The balance should be used within a short period of time (one to two weeks).

Store in a cool, dry environment.

Store at 4°C (refrigerator). Do not freeze.

At optimal conditions, the shelf life is one year for ProRestart and six months for ProDessert, ProElif, and ProMalic.

Put the remaining beads in an intact bag. If the loss of beads is extreme, turn over the tank twice a day to circulate the beads. Also, filter after the fermentation as you would in a standard fermentation.

A maximum final alcohol tolerance of 15.5 % and a free SO2 < 20 mg/L. Previous additions of yeast hulls
 (25-30 g/hL) may considerably improve the efficiency of ProRestart due to the absorption of toxinsn.

ProRestart has been proven to work in high fructose environments. However, more fructophilic (fructose loving) standard yeast strains, such as ICV-K1 (V1116), may be preferred.

The alginate should not impart any characteristic to the wine.

No. ProDessert is not designed to withstand the more difficult conditions of a secondary fermentation. ProElif was developed for that purpose.

Tank bags should be filled with no more than 5 kg of encapsulated yeast. Tie the bags to the strings attached to the top of the tank and anchor the bag with a weight, or ballast, to prevent the bag from floating.

The recommended dosage per barrel is 164 g ProRestart, 164 g ProMalic, and 218 g ProDessert. Each dose should be divided in half and placed into two barrel bags. Place the filled and re-hydrated bags through the barrel bunghole and attach them to the top of the barrel. Using a ballast is not necessary during this process.

YAN stands for Yeast Assimilable Nitrogen. It is the sum of assimilable nitrogen from ammonium ions and the assimilable Free Amino Nitrogen (FAN) present in the juice. The recommended levels of YAN range from 250 ppm to 350 ppm or higher depending on the initial Brix level.

Go-Ferm immediately gives your desired yeast a leg up over other organisms during fermentation. Go-Ferm is added to the rehydration water of the selected, active dried yeast. A "sponge effect" allows the yeast to soak up the nutrients as they soak up the water. Micronutrients are more bioavailable to the yeast, which encourages a strong and smooth fermentation.

Go-Ferm should be added in the rehydration water of the active dried yeast prior to the yeast addition itself. The recommended dose is to add 2.5 lb of Go-Ferm/1000 gal (of total juice/wine) into twenty  times its weight of clean 43°C(110°F) water. Then stir the GoFerm to dissolve. For optimal performance, maintain a ratio of 1 part yeast to one and one fourth part Go-Ferm.

Fermaid K is best added at one third of sugar depletion at a rate of 2 lb/1000 gal. Fermaid K should be hydrated before adding it to an active fermentation in order to avoid CO2 release and an overflow of tanks or barrels.

DAP should be used when YANC is below 125 mg N/L. Fermaid K contains some DAP, but for very low Nitrogen content must, DAP is recommended in order to bring YANC to above 150 mg N/L. Each 2 lb/1000 gal (25 g/hL) addition yields 50 mg N/L of inorganic (ammonium) nitrogen.

Nitrogen levels can be tested through formol titration or the NOPA method. Inorganic nitrogen can be determined by using an ammonia probe.

Some nutrients do not conform to organic qualifications while others are tailored for this purpose. For organic wine, we suggest using Go-Ferm, Go-Ferm Protect, Fermaid O, or SIY 2133 (Fermaid 2133).

SIY 33 (Fermaid 2133) is a whole yeast cell powder providing amino nitrogen and B vitamins. Fermaid K is a blended complex yeast nutrient containing Magnesium Sulfate, Inactive Yeast, Thiamine, Folic Acid, Niacin, Biotin, Calcium Pantothenate, and DAP.

Use yeast hulls to fine out toxins in the case of sluggish/stuck fermentation to increase the surface area of clarified juice and to supplement survival factors such as sterols.

The only nutrient that conforms and is documented as Kosher is Fermaid K (Kosher).

Opti-RED is basically a highly specific form of autolyzed yeast. There are some benefits derived from this organic nitrogen source, but the use of Opti-RED should not preclude the use of other nutrients like Fermaid K, Go-Ferm, or Go-Ferm Protect.

Pantothenate helps keep open important metabolic pathways that dramatically reduce the production of H2S. Magnesium improves yeast alcohol tolerance.

Yes. Each strain has distinct fermentation kinetics. One strain may require less of one nutrient compared to another strain. Do your research. See the individual product descriptions to help determine your yeasts' specific needs

Yes. Yeast metabolizes nutrients at different times throughout fermentation. Dosing nutrients at the most optimal moments can enhance yeast performance. As fermentation progresses and the ethanol level rises, yeast becomes less and less able to assimilate nutrients. For this reason, each nutrient has been created for specific addition times. For example, GoFerm has been designed to add during rehydration. Other nutrients like Fermaid K are added at one third sugar depletion and never into the rehydration water.

Tannins are best added early in the winemaking process. In red wine, during the fermentation stage, an addition integrates tannin into the wine, offering the greatest opportunity for color stability and increased middle palate structure. They can be added at the crusher or to the tank during the first pump-over, depending on the grape quality (rotten vs. sound). Additional tannin can be added with each pump-over. If adding tannins to a white wine, add them directly to the grapes at the crusher or to the tank during a tank mixing.

Using all three products together is fine, but timing is important! High SO2 content can inhibit enzyme activity. Do not add SO2 and enzymes at the same time. It is okay to add enzymes after the SO2 is adequately dispersed or to add SO2 after the enzymes are adequately dispersed. Follow this process with a tannin addition six to eight hours later. When enzymes are not being used, add SO2 first, allow SO2 to disperse, then follow with the tannin addition.

Yes, a tannin addition in white juice may be beneficial to remove off-aromas, improve clarification,  inhibit laccase activity from Botrytis or rot, or serve as an anti-oxidant. We recommend using either Uva’Tan, Uva’Tan Soft, FT Blanc, or FT Blanc Soft. Tannins can also be added later to wine to improve mid-palate structure or softness.

Tannins can be used to protect the color and phenolic structure of your wines. For the easiest and most efficient integration of tannins, add FT Rouge or FT Rouge Soft at the crusher. If needed, an addition of Uva’Tan, Uva’Tan Soft, or Tannin Estate, prior to aging, can help reinforce phenolic balance. During long maturation in barrels, Tannin Estate will help prevent excessive oxidation that can result in loss of structure and freshness. For improved SO2 management, add small amounts of Tannin Estate (5-7.5 g/ hL) during each racking.

Tannins do not add color to the must of low color grapes. Recent research indicates that early addition of tannins, such as FT Rouge, allows them to bind up available proteins. This preserves the grapes’ own natural tannins to be available to bind with the grapes’ anthocyanins, thereby providing an increased color stability.

Oak chips are a cheap source of ellagic (wood) tannin. Though they may help to mask flavors, provide some oxidative protection, and leave an oak finish, they WILL NOT improve the mid-palate structure. By contrast, the combination of wood and proanthocyanidic tannins in FT Rouge or FT Rouge Soft will help improve structure and color stability.

If more tannin structure and flavor is desired post-fermentation, make additions with Tannin Complex or Tannin Estate. Additions are best before barrel aging when tannins can be incorporated into the wine and oxidation and polymerization are slow. Tannin Refresh, Tannin Riche and Tannin Riche Extra are the best tannins to use prior to bottling (three to six weeks) when a bit of oak influence is desired. Any of these tannins can be used throughout winemaking, depending on the desired effect. Bench trials are required to determine the best tannin for a particular wine or style.

Tannins protect wine from oxidation during barrel aging. The wood tannins extracted from a new barrel protect the wine from over-oxidation during the slow process needed for tannin polymerization and wine development. When using old barrels, indigenous tannin may be completely leached out. A small tannin addition of 5-10 g/hL will act as an anti-oxidant and help protect the wine. Attaining a good phenolic profile will slow the maturation process and still protect the wine.

Yes. Over-astringency is caused by an imbalance of tannin molecules or by insufficiently bound tannin complexes. By adding a more refined, highly polymerized tannin to the wine, the imbalance can be corrected and the perception of astringency or bitterness is reduced. Frequently, this improves the perception of fruit.

Uva’Tan (tannins from grape skins and seeds) and Uva’Tan Soft (tannins from grape skins only) are comprised of 100% grape tannin. All other tannins are sourced from a combination of grapes, exotic woods, oak, or chestnut.

Direct inoculation cultures can be directly added to wine after being rehydrated. Quick build-up cultures require a simple twelve or twenty-four hour rehydration step using an acclimated culture of Oenococcus oeni and an energizer/activator (included in kits). Standard cultures must go through a build-up protocol prior to inoculation of the wine. The standard build-up process can take from five to twenty days to prepare.

ML should be inoculated at the end of primary fermentation. This helps avoid competition with the yeast that can lead to stuck fermentations. Bacteria can also produce large quantities of volatile acidity (VA) while fermentable sugars are present.

An optimum environment for malolactic bacteria includes a temperature between 20-25°C (68-77°F), alcohol below 13% (v/v), total SO2 below 25 ppm, pH above 3.4, little or no oxygen, low levels of short and medium chained fatty acids, low levels of organic acids, and low levels of polyphenols.

If your wine is bordering the optimal limits for the bacteria environment, nutrients may be desired. Malolactic rehydration nutrients like Acti-ML can provide an increased surface area to keep bacteria in suspension and can help strengthen the bacteria growth under difficult conditions. Other nutrients like Opti'Malo Plus can be useful to create an environment that promotes clean and quick MLF.

If your VA is creeping,  you may already have lactic acid bacteria (LAB) present in your wine. Before inoculating, first control the VA problem by assessing contamination and treating the area with lysozyme, SO2, or whatever is appropriate for the situation.

Air traps can be used to see if metabolism is occurring in the wine. Also, paper chromatography can be used to monitor the production and reduction of lactic and malic acids. Another method is to listen for the small bubble "spritzing" usually found in these fermentations.

Traditionally, SO2 has been used to control the rate and occurrence of MLF, however lysozyme can be used to effectively control the aspects of MLF and reduce the total amount of SO2 needed. Ultimately, sterile filtration is the best way to ensure complete removal of malolactic bacteria.

A bacteria culture will retain some of its viability even after being opened. Once opened, however, the bacteria media will become susceptible to contamination. Exposure to moisture in the air can encourage the bacteria to start growing in the package, thus reducing viability significantly.

For short periods of time, bacteria can be stored in the refrigerator at 40°F, but for longer viability,  store in a freezer below 32°F. Be sure to let the bacteria sit at room temperature before beginning rehydration.

Cultures are marked with production dates and expected viability under different temperatures. (twelve months at 40°F and eighteen months at 0°F.)

Diacetyl is the chemical responsible for the buttery character found in white wines that undergo MLF. Diacetyl is formed as a by-product of the catabolism of pyruvate, which is often derived after MLF from citric acid sources. Citrate and oxygen concentration will increase diacetyl levels, while living yeast cells and SO2 levels in the wine will reduce concentrations. The ML strain used will also have an effect based on its catabolism of citric acid. Thus, there are multiple factors to think about when addressing the "butter issue". The initial state of the wine, winemaking method (for example sur lies),  and choice of bacteria strain all must be considered.

An even distribution is important. First, calculate the dosage, then dilute Scottzymes to approximately a 10% solution (v/v) in cool water. Sprinkle the solution over the crushed grapes/fruit or during a pump-over before fermentation. If adding liquid enzymes to wine, gently mix a 10% solution into the tank for an even dispersion.

Granular enzymes need to be dissolved in ten times their weight in water, gently stirred, and allowed to sit for a few minutes. Then, they are ready to be added to juice or wine. Powdered enzymes tend to scatter across water or wine. So, it is best to add just enough cool 21-25°C(70-77°F) water to the enzyme to create a paste. Next, add more cool water to dissolve the enzyme completely. Now, it is ready to be added to the tank. Make sure you have gentle motion in the tank to disperse the enzyme or use a dosing pump.

Rehydrated powdered/granular enzymes should not be kept in liquid form for more than a few hours at room temperature. The liquid solution of these enzymes may be kept a few days at 4°C(39°F) in water acidified with tartaric acid to pH 3.5 with 50 mg/L of SO2.

Yes, enzymes are inhibited by SO2. Deactivation occurs around 200 ppm. Do not add SO2 and enzymes together. It is okay to add enzymes after the SO2 is adequately dispersed or to add the SO2 after the enzymes are adequately dispersed.

You may still use enzymes,  but not until the wine has been racked off the bentonite. Bentonite inactivates enzymes, so it is best to use bentonite after the enzyme treatment is complete.

Add at the crusher or the fermenter as soon as possible. Anthocyanins are water-soluble and release as the grapes are being crushed. Most of a red wine’s color potential is achieved very early.

Scottzyme Color Pro improves settling, fining, and filterability of white wines.

Lallzyme EX is recommended for fruit-forward red or rosé wines. Lallzyme EX-V is formulated for premium, aged reds.

Low temperatures, alcohol, and SO2 all inhibit enzyme activity, but the enzymes will still work. This is why the recommended enzyme dosage levels for wine are higher than for juice. Reaction time will also increase when conditions are not optimal.

It is best to add Scottzyme KS after pressing and before fermentation. If added later, you will need a higher dose and a longer reaction time in the wine. If you know you have problems with a specific white wine, add Scottzyme KS to the juice tank. Preventative use is more effective and quicker. Warning: Do not use Scottzyme KS before pressing. Never use Scottzyme KS on red grapes or must.

Leftover liquid Scottzymes should be tightly sealed and stored in a refrigerated environment. Granular enzymes should be kept in a dry, cool environment. If the dry enzymes have moisture in them, they should be thrown out. If kept properly, liquid enzymes should be good for at least one year with only a small activity loss. Granular enzymes will be good for several years.

Yes, bench trials are essential to determine proper dosing and efficiency. Each fining product works under a different mechanism and will react to each wine differently. Bench trials and cellar additions should be prepared and used in the same way (same temperature, same mixing style, etc.). If bench trials are not performed, the winemaker may risk under or over-fining and could ruin the wine. Take the time to find the right dose. Your wine will thank you.

Fining can be a delicate operation. Product preparation and addition, product concentration, temperature, product age, pH, metal content, and previous fining treatments are all factors that can influence the effectiveness of fining. It is important to follow the manufacturer’s instructions and maintain accuracy when using fining products.

Gum arabic can be used to stabilize colloids in a wine and help control color drop out in reds. Astringency can be reduced, while volume and fullness in the mouth can be enhanced.

Gelatins are a good choice for the reduction of astringency. Gelatins can target harsh tannins and phenolics. Another way to reduce astringency is to add polymerized aging tannins. Bench trials are highly recommended for gelatins and aging tannins prior to use.

Often a bentonite and casein blend (Bentolact S) is a fast and easy way to reduce bitterness. If you have already protein stabilized with bentonite, try adding a small amount (25 ppm) of the Scott’Tan FT Blanc Soft to eliminate the bitterness. The Bentolact S will precipitate the bitter molecules, while the tannin will mask it. Bench trials are recommended.

Depending on the degree of oxidation, it may be necessary to use more than one product. Run bench trials with Caseine Soluble, Polycacel, Polycel, or Viniprotect. Oxidation is easier to prevent than treat. To protect organoleptic soundness, prevent oxidation by adding Bentolact S or Scott’Tan FT Blanc to white grapes in addition to using adequate SO2.

First, check for microbial contamination. If there is a microbial problem, consider SO2 and lysozyme additions (as appropriate) as well as filtration. If microbes are not found, run bench trials with Hot Mix Sparkolloid NF, Cristalline Plus (isinglass), or gelatin. Sometimes the use of enzymes can eliminate wine cloudiness. Also, bench trials with Scottzyme KS or Scottzyme Pec5L may prove useful.

Run bench trials with Hot Mix Sparkolloid NF, Cristalline Plus, and gelatin. To encourage faster sedimentation, colloidal silica (Gelocolle) can be used after gelatin fining.

Both types of Sparkolloid (Hot Mix NF and Cold Mix NF) are proprietary blends of polysaccharides in neutral carriers. Both types exhibit a strong positive charge that neutralizes and complexes with clouding particles. Developed in house, Cold Mix is for juice and Hot Mix is for wine. Both are powerful fining agents available at a minimal cost.

Isinglass (Cristalline Plus) is used for applications with white and rosé wines. Made from the swim bladders of fish, this fining agent is proven to enhance clarity and brilliance, even in wines made from botrytised grapes.

Carbon, silica sol, oak chips, and tannin will bind and precipitate lysozyme, resulting in a decrease in activity. Bentonite will bind with and inactivate lysozyme.

Gelatin, potassium caseinate, and pectinase do not affect lysozyme activity. In fact, pectinase treatment will help maintain lysozyme activity by breaking down phenolic compounds that can bind lysozyme.

There are several ways to add fining agents: add the fining agent to the tank while mixing with a Guth agitator, dosing into a recirculation pump setup with a stand-alone dosing machine, or with a Mazzei injector.