The first description of brewing beer with marine yeasts

Abstract

      Most of the yeast species we encounter daily are terrestrial, but they are also found in the marine environment. Marine yeasts occur in estuaries, coastal and open marine waters, sediments, and as epi- and endobionts of various marine organisms. This study focuses on the fermentation capabilities of marine yeasts isolated from the central Adriatic Sea for use in the brewing process. Sampling was performed at a sea temperature of 12°C to avoid collecting yeasts introduced into the marine environment by human activities. Four nutrient media designed for yeast isolation and growth were used to isolate yeasts from the marine samples: Yeast Malt Agar (YM), Yeast Malt Agar with antibiotics, acidified Yeast Malt Agar, and Sabouraud Dextrose Agar. Sixteen yeast colonies were successfully isolated, and only three were positive in the fermentation test and were further determined to species level. Of the three species identified as capable of fermentation, Candida famata completely fermented the wort and produced a beer. Candida pelliculosa fermented slowly over an extended period and did not produce a usable beer, while Candida sake did not ferment the wort at all. To our knowledge, this is the first time that marine yeast isolates have been used experimentally for beer fermentation, indicating potential for use as nonconventional yeasts in brewing and beer production. Further investigations should include professional standard fermentation, aroma and genetic studies.