As with any fermented product, citric acid presents multiple kosher concerns. It is essential to seek out citric acid certified by a reliable rabbinic authority, especially for Passover.

See our list of certified Kosher citric acid

What Citric Acid Is

Originally, citric acid was isolated from citrus fruits, but today it is derived through fermentation.

Citric acid is present in virtually all living organisms and is responsible for cellular metabolism. It is the component in citrus fruit responsible for that characteristic sour flavor.

How Citric Acid Is Used

Citric Acid is almost completely non-allergenic and very soluble, making it useful in a wide variety of settings, from confectionary manufacturing to soft drink production.

In retail, including kosher food products, citric acid is sold under the label “sour salts”. Industrial applications include preservative, anti-oxidant, flavor enhancer, emulsifying agent, digestion aid and as a cleaning solution. Citric acid is also used to balance the pH in foods (acidulant).

How Citric Acid is Made

Originally, citric acid was isolated from citrus fruits, but today it is derived through fermentation. Though almost all organisms produce citric acid, certain strains of the fungus Aspergillus niger and the yeast Candida oleophila are prone to produce excess citric acid when stressed. These organisms are isolated and grown on a carbon substrate such as molasses, cane syrup, corn steep liquor and even glycerol and brewery wastes. After filtration, the citric acid is precipitated with lime and regenerated with sulfuric acid.

Citric Acid and Kosher

As noted, fermentation presents multiple kosher concerns. A kosher question may be raised by non-kosher nutritional broth that can be used to maximize and/or stimulate production of citric acid fermentation. However, since the broth is essential to the actual citric acid production, many halachic authorities will allow the leniency of botul b’shishim (less than 1/60th) in this situation.

In addition, many of the substrates used in the fermentation process may be derived from kitniyos or even outright chometz. Especially for Passover, it is essential to seek out citric acid certified by a reliable rabbinic authority. The same is true for ingredients composed of citric acid, such as sodium citrate or calcium citrate (a common vitamin supplement).

As with all kashrus issues, specific questions should be discussed with a knowledgeable Orthodox rabbi.