Molecular sulphur dioxide is the most affective form involved in both the reduction of oxidation reactions and microbial activity in wine.
The recommended level of molecular SO2 for red wines is 0.5 mg/L (ppm); for white wines is 0.8 mg/L (ppm); and for dessert wines is up to 1.5 mg/L (ppm). You can use this calculator to determine how much Free SO2 is required to protect your wine, based on its pH. Free SO2 over 50 mg/L (ppm) can be tasted and detect in nose of the wine.
|Desired Molecular SO2|
|pH of the Wine|
|Required Free SO2|