Molecular SO₂ Formula:
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Definition: This calculator estimates the molecular SO₂ concentration in wine based on free SO₂, pH, and other parameters.
Purpose: It helps winemakers determine the effective antimicrobial and antioxidant protection in their wines.
The calculator uses the formula:
Where:
Explanation: The formula calculates the equilibrium concentration of molecular SO₂, which is the active antimicrobial form.
Details: Molecular SO₂ is critical for wine stability. A concentration of 0.5-0.8 mg/L is typically needed for microbial stability.
Tips: Enter the free SO₂ (mg/L), wine pH (default 3.2), conversion factor (default 0.5), and pKa (default 1.81). All values must be > 0.
Q1: Why is pH important in SO₂ management?
A: pH dramatically affects SO₂ equilibrium - lower pH means more molecular SO₂ at a given free SO₂ level.
Q2: What's a typical target molecular SO₂ level?
A: Generally 0.5-0.8 mg/L for microbial stability, though this depends on wine type and condition.
Q3: When would I change the conversion factor?
A: The 0.5 factor is standard, but some winemakers adjust based on specific conditions or measurements.
Q4: How do I measure free SO₂?
A: Free SO₂ is typically measured using aeration-oxidation or other analytical methods.
Q5: Does temperature affect this calculation?
A: Temperature slightly affects the equilibrium, but pH has a much greater impact in normal winemaking ranges.