Calcium - oxalic acid - technological importance

It is well known that Ca-oxalate precipitates act as crystallisation nuclei. Carbon dioxide is set free at these nuclei, this may contribute to gushing of beer and may also reinforce this phenomenon. This article describes factors promoting formation of Ca-oxalate crystals and the possibilities of taking preventative measures.

Calcium has a special significance when it occurs together with oxalic acid and can form with the latter calcium precipitates (Ca-oxalate) in beer. In addition to the accepted factors such a fusaria infestation of barley or malt, also referred to as "malt-based" gushing, or excessive iron concentrations in bottled beer, these Ca-oxalate precipitates are regarded increasingly as possible contributors to gushing. 3).
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