Wine Business SO2 Calculator

Molecular SO₂ Formula:

\[ [SO₂] = \frac{k \times FSO₂}{1 + 10^{(pH - pKa)}} \]

Free SO₂ (FSO₂):

mg/L

Wine pH:

Conversion Factor (k):

Dissociation Constant (pKa):

Molecular SO₂ ([SO₂]): mg/L

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1. What is a Wine Business SO2 Calculator?

Definition: This calculator estimates the molecular SO₂ concentration in wine based on free SO₂, pH, and chemical properties.

Purpose: It helps winemakers determine the effective antimicrobial concentration of sulfur dioxide in their wine.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ [SO₂] = \frac{k \times FSO₂}{1 + 10^{(pH - pKa)}} \]

Where:

\( [SO₂] \) — Molecular SO₂ concentration (mg/L)
\( FSO₂ \) — Free SO₂ concentration (mg/L)
\( pH \) — Wine pH (dimensionless)
\( k \) — Conversion factor (dimensionless, typically 1)
\( pKa \) — Dissociation constant (~1.81 for SO₂)

Explanation: The formula calculates the proportion of free SO₂ that exists in the molecular form, which is the active antimicrobial component.

3. Importance of Molecular SO₂ Calculation

Details: Proper SO₂ management ensures wine stability, prevents microbial spoilage, and maintains wine quality while minimizing sulfur additions.

4. Using the Calculator

Tips: Enter the free SO₂ concentration (mg/L), wine pH (default 3.3), conversion factor (default 1), and pKa value (default 1.81).

5. Frequently Asked Questions (FAQ)

Q1: Why is molecular SO₂ important?
A: Molecular SO₂ is the active antimicrobial form that protects wine from bacteria and yeast. The target range is typically 0.5-0.8 mg/L.

Q2: How does pH affect SO₂ effectiveness?
A: Lower pH increases the proportion of molecular SO₂ at any given free SO₂ level, making SO₂ more effective in acidic wines.

Q3: When would I change the pKa value?
A: The pKa of SO₂ is approximately 1.81 at 20°C. This might vary slightly with temperature but rarely needs adjustment.

Q4: What's a typical free SO₂ target?
A: Depending on pH, free SO₂ targets range from 10-50 mg/L to achieve the desired molecular SO₂ level.

Q5: Does this calculation account for bound SO₂?
A: No, this calculates only the molecular SO₂ from free SO₂. Total SO₂ would include both free and bound forms.