Skip navigation

Dealing with Botrytis in the Cellar

SO2 additions

For light Botrytis infections, 30 ppm to harvest bins, then 20-30 ppm after crushing and destemming (if applicable). For heavy infections 40+ ppm and then 30-40+ ppm respectively. This might need to be all at once for whites. A CO2 or inert gas cover should be employed as much as possible to limit oxidation potential.

Ensure SO2 protection after fermentation as Acetobacter populations might still be high enough to cause trouble. Keep a close eye on FSO2 levels and tightly limit/eliminate oxygen exposure.

Product detail: Potassium metabisulfite 1 kg & 25 kg


Enzymes can be extremely useful in high Botrytis pressure harvests. For whites, the use of enzymes during settling can reduce beta-glucans, pectins and other undesirable substances and microorganisms that often occur in elevated levels in compromised fruit. Beyond that, appropriate enzyme usage can speed the settling process and increase clean juice yields. Enzymes are deactivated by bentonite so should be used immediately at pressing.

Bactozym® (lysozyme) reduces populations of gram positive spoilage bacteria like LactobacillusPediococcus and Oenococcus that may be at higher populations in compromised fruit.

Product detail: Bactozym® 100 g & 500 g

Mannozym® is a Beta-glucanase with lysogenic activity. It will help break down the beta-glucans so prevalent in Botrytized grapes. These can severely decrease clarification and filterability. The lysogenic activity in Mannozyme also liberates mannoproteins from yeast cells increasing mouthfeel and richness, very useful for wines that have body stripped by Botrytis related thinning.

Product detail: Mannozym® 500 g

Zimaclar® is a pectolytic enzyme that can help rapid settling of must, allowing you to rack off cleanly and quickly and thus limiting the negative sensory impact of compromised fruit.

Product detail: Zimaclar® 100 g, 500 g & 20 kg

Zimared® Plus is a pectic enzyme with multiple functions aimed at breaking down grape skin cell walls in the initial phase of fermentation, assisting the liberation of color and tannin compounds and helping create stable color-tannin complexes that are often difficult to achieve with Botrytized fruit. This also reduces the need for excessive extraction and hard pressing in reds, thereby reducing some of the negative compounds associated with poor quality fruit.

Product detail: Zimared® PLUS 100 g, 500 g & 20 kg

Extrared L is a related product that is used later in red fermentations (hours before pressing) to assist in the extraction and stabilization of color compounds. It should not be used when green seeds are present.

Product detail: Extrared L 1 L


Flotation is a great way to deal with Botrytis compromised fruit. The quick clarification and racking time limit the negative effects of polyphenol oxidase and many of the other difficulties faced with this situation. Flottozima P (powder) and Zimaclar Flot (liquid) are specifically engineered for maximum efficiency in breaking down pectins and promoting flocculation, enhancing flotation effectiveness.

Flottobent DA can be very fast and effective bentonite treatment for removing laccase. Flottocarb DA can quickly and effectively remove oxidation susceptible anthocyanins and oligomers, limiting color issues.

     Product detail: Flotation Products

  • Flottozima® P 500 g
  • Zimaclar® Flot 1 L & 25 kg
  • Flottobent® DA 5 kg & 25 kg
  • Flottocarb® DA 10 kg,


Affected white grapes should be whole cluster pressed if possible and fined early during settling. There are a number of options for clarification in this situation.

Bentonite early on whites, during settling. This reduces laccase enzyme concentrations that might cause oxidation and color issues. This might also strip out proteins that provide nutrition to yeast, though, requiring appropriate nutrient addition after treatment.

Product detail:

PVPP can also help during prefermentation settling by stripping browning and oxidized compounds out of affected juice.

Product detail: Divergan® F 1 kg, 3 kg & 20 kg


The addition of enological tannin to both red and white must can provide some level of protection to Botrytis affected grapes by binding with laccase and acting as an anti-oxidant. Beyond that, addition of tannins to wine later on can improve structure and mouthfeel, which are often degraded in wines from compromised fruit. BSG offers a number of powdered tannins that can help in this situation.

Premium UVA SG is derived from ripe grape skins. It is highly reactive towards proteins including polyphenol oxidase. This also significantly contributes to protein stability, reducing the amount of bentonite that might be needed later. It is also very good at binding and stabilizing anthocyanins that might otherwise be lost. These characteristics make Premium UVA SG a very useful tool when dealing with Botrytised red and white grapes.

V Tan UVA SG is a high quality and very economical harvest blend of ellagic, gallic and catechinic tannins specifically designed for use in red wines. It is highly active with gallic and catechinic tannins binding with oxidative proteins, especially polyphenol oxidase. The catechinic and ellagic tannins help stabilize anthocyanins, ensuring you get the most stable color possible. The integration of ripe grape skin tannins can contribute richness and body to mouthfeel. There is no quebracho in this product, so no rough, bitter tannin to fine back out later.

For red wines specifically, Premium Color SG will help deactivate polyphenol oxidases, stabilize color and enhance color extraction over time. It can be added right at the start of maceration through post-press racking and has little sensory impact besides enhanced color. It is a blend of ellagic, gallic, catechin and procyanidic tannin. The diversity of active tannins is well suited to Botrytis compromised red grapes.

Product detail: Tannins


While proper yeast nutrition is important even in the best of conditions, during harvests with high Botrytis stress it becomes critical. Compromised fruit can often have much lower YAN and beneficial fermentation nutrients due to the consumption by spoilage organisms. In order to ensure healthy, quick and clean fermentations, sufficient and appropriate nitrogen, vitamins & minerals must be present the must. Superferm®, Superfood® and Startup® are excellent sources of such nutrition. Superferm® was developed specifically for high risk fermentations. It has a significantly higher vitamin content than other nutrient blends and 25% DAP. For Nitrogen deficient grapes, Superfood® complex blend is appropriate with 32.5% DAP. Startup® is excellent for yeast rehydration and musts with sufficient Nitrogen as it does not contain any DAP. Check your YANs and adjust to a sufficient level! Timing additions is even more important under stressed conditions. Adding sequentially is key for yeast to effectively metabolize nutrients and not produce stress-induced compounds.

Product detail:

Yeast & ML Bacteria

When dealing with a lot of Botrytis, it is advisable to use strong commercial strains at higher than usual pitch rates. Good S02 tolerance is helpful due to the higher dosage needed at crush/press. Quick starting yeasts (with good ML compatibility when appropriate) are highly desirable. Premium SuperTuscan and Premium Zinfandel are good choices for reds. Premium Chardonnay and Nouveaux Ferments would be good white options.

Product detail:

For ML fermentation, inoculate with strong population as soon as possible after primary fermentation complete (or before it is finished). This will give as little opportunity as possible for spoilage organisms to take hold before sulfuring. Appropriate nutrient content is important for ML just like for yeast. Leucofood can help ensure a healthy and complete ML fermentation.

Product detail: