Used mainly for acidifying a new oak barrel or when cleaning a used barrel. Always dissolve in water before adding. Use 2 teaspoons for every 5 gallons of barrel capacity. Can also be added to potassium metabisulfite sanitizing solution to lower pH and make the sanitizing solution more effective.
Occasionally used to acidify white wines for a specific flavor note, but care must be taken as it can be unstable. Generally, tartaric acid is preferred for acidifying wine.