Acids Used in Homebrewing

Learning How to Use Acids in Your Homebrewed Beer

Jan 26, 2009 Marty Nachel

A number of different acids may be introduced to beer at various stages in the brewing process, each with its own purpose. Acids may serve as additives, preservatives, or clarifiers, and they should be readily available at well-stocked homebrew stores.

The following is a list of those acids and general descriptions of how they can aid you in the beer-making process. Exactly how you use these acids depends on your needs. Be sure to always follow package directions; when misused, acids can easily ruin an entire batch of beer.

• Ascorbic: This is an antioxidant, which qualifies it as a preservative. Ascorbic acid protects beer from the off aromas and tastes associated with oxidation. This acid is also known as vitamin C. Use 1/2 teaspoon per 5-gallon batch (overuse lends a citrus flavor to your beer). Add to beer at bottling time.

• Citric: Citric acid protects against haze, increases the acidity of brewing water, which lowers the pH, and aids in the fermentation process. It is also found premixed in Acid Blend (see below).

• Lactic: This is a mild acid that is used to acidify (lower the pH of) the mash or sparge water. Lactic acid is also used to give Berliner Weisse beer its characteristic tartness. When you use lactic acid, add 1 teaspoon per 5-gallon batch just prior to bottling.

• Malic: Malic acid increases the tartness in beer. Like citric acid, malic acid is also found premixed in Acid Blend.

• Phosphoric: Used in weak dilutions (approximately 10 parts phosphoric acid per 100 parts water), phosphoric acid can be used to acidify mash water, lowering the pH.

• Tartaric: This acid increases the tartness in beer. Tartaric acid is also found premixed in Acid Blend.

* Acid Blend is a pre-mixed, prepackaged product that is a blend of citric, malic and tartaric acids. It is most often used to offset and balance overly sweet beverages such as sweet meads. Acid Blend, because it is a pre-mix, is rarely used in beer-making.

The Acid Test

It should be noted that other acids occur naturally in beer –that's both good and bad. The “good” acids would be those that are imbued in the beer by way of the hops.

When hops are boiled in wort, their lupulin glands release resins that contain alpha and beta acids that impart their flavor compounds (bitterness) and protective compounds (stability) to the beer.

The “bad” acids that occasionally occur in beer are acetic and lactic acids that are produced by bacteria. Lactic acid is created by lactobacillus bacteria and acetic acid is produced by acetobacter bacteria. The effect on the beer is a milky lactic taste or an acetic vinegary taste, both of which are very unpleasant on the palate.