Required SO2 to add considering current FSO2, pH and desired molecular FSO2 target


Use this calculator to determine the amount of SO2 to add in order to achieve a desired molecular SO2 target.


This calculator will calculate the level of molecular SO2 in a wine based on its pH and measured free SO2. The required level of molecular SO2 for antimicrobial protection is often given as 0.8mg/L, although sometimes can be up to 1.5mg/L.
In red wines, most of the 'free' SO2 is actually pigment (anthocyanin) bound, and is released by acidification of the sample prior to measurement. Due to this it is not possible to ascertain the level of molecular SO2 in red wines. Red wines are however, generally far more microbial stable than whites, and thus are typically maintained at lower levels of free SO2. In summary, maintaining high molecular SO2 in red wines is difficult and not advised - do not use this calculator as a guide for red wines.


  • Wine Science: Principles and Applications (2008) by Ron Jackson - (Academic Press);

This winemaking calculator is provided to you courtesy of NuVerge Canada Inc.


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