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How much metabisulphite to add per 1000 litres of wine

To bring free SO₂ from 10 to 30 mg/L in 1000 L of wine at pH 3.4, you need to add about 35 g of potassium metabisulphite (347 mL of a 10 % solution); the molecular SO₂ will be about 0.75 mg/L.

Parameters

Result

Approximate calculation using a simplified model: for designing equipment and process modes, consult a technologist.

Calculation example

Wine volume
1 000 l
Wine pH
3,40
Free SO₂ now
10 mg/L
What is known
I know how much free SO₂ is needed
Required free SO₂
30 mg/L
Potassium metabisulphite to add
34,7 g
SO₂ to add
20,0 mg/L
That is of a 10 % metabisulphite solution
347 ml
Free SO₂ after the addition
30,0 mg/L
Molecular SO₂ after the addition
0,75 mg/L
Share of active SO₂
2,5 %

Frequently asked questions

What are free and molecular SO₂?
Free SO₂ is all the "working" SO₂ in the wine; molecular SO₂ is its active share that protects against microbes, and it depends on the pH.

The calculations are approximate: they help to assess the process and compare options, but do not replace a process design and trials on a specific raw material. This section is for reference only and contains no commercial offers.