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 is also used to make Invert Sugar for the use in British and Belgian styles, and you can make it at home. You may know it as Belgian Candi syrup, but these are little more than treated sugar. You can make it for less than half the cost and impress your friends with some mad 19th-century-ish-candy-making skills.
What you need:
- 250g raw cane sugar (not white table sugar; cane sugar imparts more flavor than plain white table sugar) I used “CSR Raw Sugar” which is available at most grocery stores.
- 0.55g Citric Acid
- 195g water
- Pot for boiling
Dissolve the sugar in the water, add citric acid, and heat to a max of 140°C simmering for anywhere between 20 minutes and 2 hours. When the temperature reaches 140°C, add a tablespoon on water, repeating until you reach the desired colour.
You will want to simmer at a medium heat and stir frequently to prevent scorching (if the heat is too low there is a chance that the sugar will crystallise on you, so make sure you have rapid bubbling).
For a very light sugar, like Clear Candy Syrup, simmer for 20 minutes. To create something similar to dark candi sugar, boil for close to 2 hours.
During longer boils add water as necessary to prevent burning and keep the temperature below 140°C.
Invert sugar can be added right to the boil, or prepared in advance. Because of the inversion that takes place, invert sugar is very stable and lasts a while. To make the light version on brew day, I start simmering during the sparge, and then done stir in some boiling water to loosen up the invert sugar then add it during the last 20 minutes of the boil.