Citric Acid can be used in sanitizing solutions to lower the pH, which will make the SO2 level more effective.
In addition, it can increase acidity at a ratio of 0.1% for each teaspoon per gallon. Adding too much, however, will create a very tart flavor. Used to boost the total acidity of wine.
Preserves Color in white wine.
Dissolve in water before adding.
Usage varies. Powdered.