SO₂ Wine Calculator
Calculate molecular SO₂ levels and required sulfite additions for wine preservation
Calculate SO₂ Levels
Different wine types need different SO₂ levels
Measure with pH meter or test strips
Measure with SO₂ test kit or lab analysis
Auto-set based on wine type, or enter custom value
SO₂ Analysis Results
Current Wine Status
Target & Required
Formula: Molecular SO₂ = Free SO₂ ÷ (1 + 10^(pH - 1.81))
Calculation: 0.00 = 0 ÷ (1 + 10^(0.00 - 1.81))
Recommended SO₂ Levels
These are target molecular SO₂ levels for proper wine preservation
SO₂ Quick Guide
Free SO₂
Total unbound sulfur dioxide
Molecular SO₂
Active antimicrobial form
pH Impact
Lower pH = more effective SO₂
Addition Timing
Best after fermentation completion
Understanding SO₂ in Winemaking
What is SO₂?
Sulfur dioxide (SO₂) is a preservative used in winemaking to prevent oxidation, inhibit unwanted microorganisms, and maintain wine quality. It exists in both free and bound forms in wine.
Why Add SO₂?
- •Prevents oxidation and browning
- •Inhibits bacteria and wild yeast
- •Extends wine shelf life
- •Maintains fresh flavors and aromas
Forms of SO₂
Free SO₂
Unbound sulfur dioxide that can be measured directly
Molecular SO₂
Active antimicrobial form - the actual preserving agent
Bound SO₂
Combined with wine compounds - not protective
Key Point: Only molecular SO₂ provides antimicrobial protection. pH determines how much free SO₂ becomes molecular SO₂.
Adding SO₂ to Wine
Potassium Metabisulfite
Most common choice - 1g provides 57.6 mg/L SO₂ per 100L wine
Campden Tablets
Convenient pre-measured tablets containing potassium metabisulfite
Sodium Metabisulfite
More potent - 1g provides 67.4 mg/L SO₂ per 100L wine
Best Practices
- ✓Always dissolve SO₂ compounds in water first
- ✓Add gradually while stirring wine
- ✓Test SO₂ levels 24 hours after addition
- ✓Monitor levels regularly during storage
- ✓Adjust levels before bottling