These tablets are made from sodium or potassium metabisulfite in a precisely measured dose to help the home winemaker. One tablet treats 1 gallon of wine. Crush the tablets and dissolve them in a little water or wine before adding. Campdem tablets can be used before fermentation or after your second to thrid rack to stablize your wine. However, with our fresh juice we dont recommend using tablets before fermentation Just because our juice are balanced and corrected with all its properties directly from our growers in California. When crushing grapes it is recommend to add before fermentation and you should wait 4 to 24 hours before adding yeast as the sulfur dioxide will tend to slow the yeast down.