The stabilization of beer through tannin addition.

De Clerck, J.

Abstract
Gallo tannin precipitates protein more strongly than wort tannin. Oxidized tannins cause precipitation of beer haze and after tannin treatment access of air to the beer must be avoided. The correct tannin dosage for beer was estimated by adding 0 to 10 g/hl and either measuring residual complex N with picric acid or by Lundin analysis or by testing for excess tannin in the treated beer with iron at pH 10. Optimum addition for beer from the pilot brewery was 7/hl. This addition did not affect isohumulone content, foam stability or taste. Commercial tannins are mixtures of polyphenols and compared with Merck "pure" tannin showed activities 84 to 100%. The haze stability of beers treated with 6 and 8 g/hl of 7 different tannins with and without further addition of proteolytic enzyme was tested at 60 degrees C. The addition of enzyme always gave better stability and this was more marked where the particular tannin or the lower rate of addition alone gave poor stability. Tannin should be added when beer is transferred to storage tanks and the further addition of proteolytic enzyme made after filtration.
Keywords: additive beer stabilisation tannin