SO2 Wine Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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Food calculations often look simple until units, serving sizes, or recipe assumptions start changing. The SO2 Wine Calculator keeps one task focused: it helps you calculate molecular SO₂ from free SO₂ and wine pH and estimate the free SO₂ needed for a target molecular level. That makes it easier to check the math, compare two scenarios, and avoid carrying an unrelated assumption into the recipe.

What this calculator does

The SO2 Wine Calculator uses the fields on this page to calculate molecular SO₂ from free SO₂ and wine pH and estimate the free SO₂ needed for a target molecular level. Its primary output is labeled “SO₂ in wine” and is displayed in mg/L molecular SO₂. Supporting readouts include Free SO₂, Desired molecular SO₂, Required free SO₂.

How to use it

Enter or select Free SO₂, Wine pH, Desired molecular SO₂. Use the units displayed beside each quantity and change only the assumptions that describe your real recipe or event. The SO2 Wine Calculator then recalculates the primary result and its supporting values from those visible inputs.

How the calculation works

The molecular fraction is calculated from pH as 1 ÷ (1 + 10^(pH − 1.81)). Molecular SO₂ = free SO₂ × fraction; required free SO₂ = desired molecular SO₂ ÷ fraction.

Example

With Free SO₂ = 30 mg/L, Wine pH = 3.4, Desired molecular SO₂ = 0.8 mg/L, the calculator returns 0.752 mg/L molecular SO₂ for “SO₂ in wine.” The same run also shows Free SO₂ = 30 mg/L; Desired molecular SO₂ = 0.8 mg/L; Required free SO₂ = 31.92 mg/L. Changing one input at a time makes it easy to see which assumption is driving the result.

How to interpret the result

For the SO2 Wine Calculator, read the result as a process-calculation target. Small changes in measurement can matter, so keep the original inputs with the result and use appropriate brewing, winemaking, or baking measurements when precision affects the finished product.

Limitations and notes

Wine SO₂ management depends on binding, measurement method, legal limits, and product composition. Verify additions with a validated winemaking method and local requirements.