Citric acid can be used in the beer, wine, and cheese making process.

It is the primary acid in fruits like lemon, lime, grapefruit, and orange. It is a popular acid among winemakers for adjusting acid in fruit wines as well as grape wines. However, it will decompose in the presence of malolactic bacteria, forming diacetyl which could cause a vinegar aroma.
Usage: 1 teaspoon per gallon of wine increases the acid by 0.15%.

Another use for citric acid is in wine barrel treatment. It is used as an acidifier, lowering pH, when combined with sulfites in a rinsing solution. However, when using citric acid in this application, do not mix it with high alkaline solutions like sanitizers. The release of potentially harmful gases is possible.

In cheese making, citric acid is one of the commonly used acids to aid coagulation when making soft bag cheeses.

Citric Acid can be used in sanitizing solutions to lower the pH, which will make the SO2 level more effective. It is also used to increase acidity at a ratio of 0.1% for each teaspoon per gallon in wine.

Be careful with how much you add to your wine because you will get a very tart flavor if you use to much.

Use for acid adjustments in fruit wines. Adjusting acid to taste in fully fermented grape wines. Also used in barrel care as an acidifier (lowers pH) when combined with sulfites in a rinsing solution. 1 teaspoon equals approximately 3.6g. Do not mix with highly alkaline solutions (e.g. sanitizers). Release of potentially harmful gases possible. Citric acid will decompose under the influence of malolactic bacteria, forming diacetyl, and may cause arise in volatile acidity (vinegar aroma). Use in unfermented grape wines is not recommended.

Citric acid is often added to wines to increase acidity, complement a specific flavor or prevent ferric hazes. It can be added to finished wines to increase acidity and give a “fresh” flavor.