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How much SO₂ white wine needs at pH 3.6

To get 0.8 mg/L of molecular SO₂ at pH 3.6 you need about 50 mg/L of free SO₂; for 5000 L of wine with 5 mg/L already present that is about 390 g of potassium metabisulphite.

Parameters

Result

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

Calculation example

Wine volume
5 000 l
Wine pH
3,60
Free SO₂ now
5 mg/L
What is known
I want a given molecular SO₂
Required molecular SO₂
0.8 mg/L (whites and rosés)
Potassium metabisulphite to add
391,7 g
SO₂ to add
45,1 mg/L
That is of a 10 % metabisulphite solution
3 917 ml
Free SO₂ after the addition
50,1 mg/L
Molecular SO₂ after the addition
0,80 mg/L
Share of active SO₂
1,6 %

Frequently asked questions

Why is more SO₂ needed at a higher pH?
As the pH rises the active share of SO₂ drops sharply: at pH 3.0 it is about 6 %, and at pH 3.8 about 1 %.

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.