Free tools for winemakers
Potassium sorbate calculator
Sorbate to keep a sweet wine from refermenting
Potassium sorbate to add
Type the volume and the wine’s alcohol.
The table stops at 14 % vol, so this uses its lowest figure, 50 mg/L.
Add it with SO₂. Sorbate keeps yeast from starting again in a finished wine, but it won’t stop a fermentation that is running and does nothing against bacteria. Bring free SO₂ up to your target at the same time.
Not after malolactic fermentation. Lactic bacteria turn sorbate into a strong geranium smell. Don’t use it in a wine that went through malolactic fermentation.
Legal limit. The EU and the OIV allow at most 200 mg/L of sorbic acid in wine, the US 300 mg/L. Check your local rules.
How do we calculate this?
The exact formulas used in this tab:
What this calculator does
Works out how much potassium sorbate to add to a finished wine so its yeast can’t start fermenting again, for example in a wine you are leaving a little sweet.
- It reads the sorbic acid the wine needs off a published table by alcohol, and turns it into grams of potassium sorbate for your volume.
- Stronger wines need less, because alcohol already holds yeast back.
The formula
Sorbic acid (mg/L) by alcohol: 10% → 150, 11% → 125, 12% → 100, 13% → 75, 14% → 50Between rows: a straight line; above 14%: 50 (Ough & Ingraham, 1960)Potassium sorbate (g) = sorbic acid (mg/L) × volume L ÷ 1000 ÷ 0.74640.7464 = 112.13 ÷ 150.22, the share of sorbate that is sorbic acidLegal limit: 200 mg/L sorbic acid (OIV, EU); 300 mg/L (US, 27 CFR 24.246)
Worked example
A tank in liters
- 1,000 L of wine
- Alcohol: 12 % vol
- Sorbic acid, from the table 12 % vol → 100 mg/L
- For the whole tank 100 × 1,000 ÷ 1,000 = 100 g
- Sorbic acid in potassium sorbate 112.13 ÷ 150.22 = 74.6%
- How much potassium sorbate 100 ÷ 0.7464 = 134 g
Add 134 g of potassium sorbate
Between two table rows
- Alcohol: 12.5 % vol
- The rows either side 12 % vol → 100 mg/L, 13 % vol → 75 mg/L
- Halfway between them (100 + 75) ÷ 2 = 87.5 mg/L
The wine needs 87.5 mg/L of sorbic acid
A volume in gallons
- 100 US gal of wine
- Alcohol: 11 % vol
- Sorbic acid, from the table 11 % vol → 125 mg/L
- The volume in liters 100 × 3.78541 = 378.5 L
- How much potassium sorbate 125 × 378.5 ÷ 1,000 ÷ 0.7464 = 63.4 g
Add 63.4 g of potassium sorbate
Questions
Where does the table come from?
From Ough and Ingraham’s trials on sweet table wines, the table most winemaking guides still use. It gives the sorbic acid needed at each alcohol level. Between rows the calculator draws a straight line. Above 14 % vol it keeps 50 mg/L; below 10 % vol it gives no figure, because sorbate alone may not hold a wine that light.
Ough and Ingraham, American Journal of Enology and Viticulture, 1960.
Why add SO₂ with it?
Sorbate only stops yeast from starting again. It doesn’t kill yeast, won’t stop a fermentation that is already running, and does nothing against bacteria. So add it to a finished, clear wine, and bring free SO₂ up to your target at the same time; the SO₂ calculator works that out.
Can I use it in a wine that went through malolactic fermentation?
No. Lactic acid bacteria break sorbate down into a compound that smells strongly of crushed geranium leaves, and it can’t be removed. Don’t use sorbate in a wine that went through malolactic fermentation, or one that still might.
How much is allowed?
The OIV and the EU allow at most 200 mg/L of sorbic acid in wine, and the US 300 mg/L. The table never goes above 150 mg/L. Rules differ by country, so check yours.
EU: Regulation (EU) 2019/934. US: 27 CFR 24.246.