How to Use Wine SO₂ Calculator
The Wine SO₂ Calculator computes the exact amount of metabisulfite or Campden to add to reach a target free SO₂ level.
- Enter wine volume in litres.
- Enter current free SO₂ — From a lab test (mg/L).
- Enter target free SO₂ — Style and pH dependent.
- Pick the additive — Potassium metabisulfite (KMBS), sodium metabisulfite (NaMBS), or Campden tablets.
- Read the dose — The Wine SO₂ Calculator shows grams (or tablets), required SO₂ increase, and total mg.
Formula & Theory — Wine SO₂ Calculator
The Wine SO₂ Calculator uses three equations:
delta_mg_per_L = target - current
total_so2_mg = delta × volume_L
additive_mg = total_so2_mg ÷ additive_yield
campden_tablets = total_so2_mg ÷ 75| Additive | SO₂ yield by mass |
|---|---|
| Potassium metabisulfite | 57% |
| Sodium metabisulfite | 68% |
| Campden tablet | 75 mg / tablet |
Assumptions and Limits
The Wine SO₂ Calculator assumes pure additive and accurate testing. Always re-test free SO₂ 24 hours after addition. Active fermentation and reductive winemaking change behaviour.
Use Cases for Wine SO₂ Calculator
The Wine SO₂ Calculator is useful for:
- Pre-bottling adjustment — Final SO₂ correction to target.
- Barrel top-up — Maintain SO₂ during ageing.
- Home winemaking — Convert KMBS grams to Campden tablets when out of stock.
- Cider and mead — Same chemistry applies.
The Wine SO₂ Calculator keeps additions precise and protects your wine without over-sulfiting.