1. What is Free SO₂ in Wine?

Free sulfur dioxide (SO₂) in wine consists of molecular SO₂ (the active antimicrobial form) and bisulfite ions. It's crucial for wine preservation and microbial stability.

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• Molecular SO₂ — The active antimicrobial form (measured in mg/L)
• Bound SO₂ — SO₂ bound to aldehydes, sugars, etc. (measured in mg/L)

Explanation: The sum of molecular and bound SO₂ gives the total free SO₂ concentration in the wine.

3. Importance of SO₂ Measurement

Details: Proper SO₂ levels prevent oxidation and microbial spoilage while ensuring wine quality and stability. Regulatory limits also exist for SO₂ concentrations.

4. Using the Calculator

Tips: Enter both molecular and bound SO₂ values in mg/L. Values must be positive numbers. The calculator sums these to give total free SO₂.

5. Frequently Asked Questions (FAQ)

Q1: What are typical free SO₂ levels in wine?
A: Typically 20-50 mg/L for white wines, 10-30 mg/L for reds, depending on pH and wine style.

Q2: How does pH affect SO₂ effectiveness?
A: Lower pH increases the proportion of molecular SO₂, making it more effective at lower total concentrations.

Q3: When should SO₂ be measured?
A: At key stages: after fermentation, before bottling, and periodically during storage.

Q4: Are there alternatives to SO₂?
A: Some alternatives exist (ascorbic acid, lysozyme) but none are as broadly effective as SO₂.

Q5: What are regulatory limits for SO₂?
A: Varies by country; EU limits are 150-200 mg/L for reds, 200-250 mg/L for whites (total SO₂).