Super-Attenuation of Beer: A Study of Three Organisms Capable of Causing Abnormal Attenuations

Three organisms have been isolated which can cause naturally conditioned beers to ferment to abnormally low specific gravities. This effect, which here is termed super-attenuation, is shown to be due to the action of diastase produced by the organisms. (1) Saccharomyces diastaticus nov. sp. A yeast which can ferment beer wort to a specific gravity well below that produced either by brewery culture yeast (Saccharomyces cerevisiae) or by secondary yeast (Brettanomyces). (2) Streptococcus damnosus var. diastaticus. A variety of Str. damnosus which can cause super-attenuation in beer by synergistic action either with culture yeast or with secondary yeast. (3) Lactobacillus pastorianus var. diastaticus. A variety of L. pastorianus which can cause super-attenuation in beer by synergistic action either with culture yeast or with secondary yeast.