
In the effort to create high quality wines, it is critical to maintain proper free sulfur dioxide (SO2) levels during all steps of the winemaking process. Keeping SO2 levels at optimum values is key to preventing the discoloration, off-flavors and unpleasant aromas resulting from oxidation and microbial contamination. Suffice to say that all those award winning wines going for $200 a bottle or more have the correct levels of sulfites added to them!
The problem with the task of maintaining SO2 levels is the tendency for this component to disappear over time. The SO2, typically added as a sulfite like potassium metabisulfite, undergoes an equilibrium between free and bound forms which is pH- and temperature-dependent. In addition, oxidation by atmospheric oxygen continually reduces SO2 levels especially when the wine is briefly exposed to air as occurs during racking and bottling. Therefore it is important to have a reliable method handy for measuring free SO2.
Keep Reading More!


