Sodium Benzoate

Sodium benzoate is supplied as a white powder or flake. During use it is mixed dry in bulk liquids where it promptly dissolves. Approximately 1.75 oz (50 g) will readily dissolve in 3 fl oz (100 ml) of water. In contrast, benzoic acid has a significantly lower water solubility profile. When placed in water, sodium benzoate dissociates to form sodium ions and benzoic acid ions. Benzoic acid is a weak organic acid that contains a carboxyl group, and occurs naturally in some foods, including cranberries, prunes, cinnamon and cloves. It is also formed by most vertebrates during metabolism.

Sodium benzoate is an antimicrobial active against most yeast and bacterial strains. It works by dissociating in the system and producing benzoic acid. Benzoic acid is highly toxic to microbes, however, it is less effective against molds. Overall, it is more effective as the pH of a system is reduced with the optimal functional range between pH 2.5-4.0. The antimicrobial effect is also enhanced by the presence of sodium chloride.