New Procedures to Improve the Flavor Stability of Beer

Palliatives for enhancing the stability of beer flavor have been evaluated by organoleptic tests, but primarily by use of an accelerated aging technique, followed by estimation of staling substances using thiobarbituric acid (TBA). TBA has also been used to trace the quantities of carbonyl compounds and their precursors through malting and brewing and in beer treated with palliatives and substances that cause flavor deterioration. Beer staling is reduced by scavengers of the hydroxyl radical (mannitol, ascorbic acid) and is increased by agents which elevate hydroxyl levels (e.g., peroxide/ metals). Staling substances develop during malt kilning and wort boiling, but primarily during fermentation. There is evidence that soybean extracts enhance the shelf life of beer flavor if included in the fermenting wort; we suggest that this action is caused by superoxide dismutase. Procedures for making soybean preparations devoid of lipoxidase include heating and soaking beans in ethanol. However, doubts are cast upon the role of lipoxidase in staling.