Back to Tools

SO₂ Addition Calculator

Calculate sulfite additions based on pH and desired molecular SO₂ levels.

Read the full guide on SO₂ management →

SO₂ Addition Calculator

Typically 0.8 ppm for dry wines, 1.0-1.2 for sweet wines

Required Free SO₂: ppm

Calculated using the formula: Free SO₂ = Molecular SO₂ × 10^(pH-1.8)

Calculate Addition Amount

Based on laboratory measurements

KMBS is ~57% SO₂ by weight, SMBS is ~52% SO₂ by weight

Addition Amount: grams

Amount = (Required Free SO₂ - Current Free SO₂) × Volume (L) / 1000 / SO₂ content

Important Notes
  • Always dissolve metabisulfite in water before adding to wine
  • Mix thoroughly to ensure even distribution
  • Recheck free SO₂ 24-48 hours after addition
  • High pH wines (>3.6) may require additional acid adjustment for stability