Citric Acid is an organic acid found in beer normally within the range of 50 to 250 parts per million. It is produced as a result of yeast metabolism and is a key component of the tricarboxylic acid cycle, which is also referred to as the Krebs or citric acid cycle.
 
 
 
Although it contributes to the overall acidity of the beer, citric acid has little impact on the overall flavor. It is sometimes added to increase the acidity of some low-alcohol and nonalcoholic beers where incomplete fermentation fails to increase acidity to an appropriate level.
 
 
 
Craft brewers and homebrewers have occasionally used additions of citric acid to lend some tartness to Belgian-style witbier; although some tartness is traditional, it has historically been the result of lactic bacterial activity. Citric acid has also been used as a cleaning agent, particularly in the removal of “beer-stone” from fermentation vessels.
 
 
 
Philliskirk, G. Citric Acid | Craft Beer & Brewing™.