Isolation, Selection and Characterization of Wild Yeasts with Potential for Brewing

Ninety-two wild yeasts were isolated from different fruits, for possible use in brewing, using the technological traits of carbohydrate fermentation and hydrogen sulfide production. Twelve yeasts were selected for identification by sequencing (D1/D2 domain or ITS1-5.8S-ITS2 region) and their volatile compounds production analyzed using gas chromatography. From these analyses, three yeasts were chosen for further characterization and beer production. Strains were characterized by their tolerance to osmotic and ethanol stress, their flocculation profile, growth at different temperatures, apparent attenuation (percentage of sugars converted into alcohol), estimated ABV (alcohol by volume) and reducing sugar profile. Beers were analyzed for alcohol content and sensorial analysis. The isolates CL011 and PB111 (Saccharomyces cerevisiae) and CB341 (Wickerhamomyces anomalus) showed promising properties for brewing, which included high production of interesting volatile compounds (esters, terpenes, lactones, and C13-norisoprenoids) by CL011, a neutral profile by PB111, and the production of non-classic beer volatile compounds by CB341 in a mixed culture. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2022.2031777 .

Automated summary

Ninety-two wild yeasts were isolated from different fruits for potential use in brewing. Three selected yeasts showed promising properties, including high production of interesting volatile compounds, a neutral profile, and the production of non-classic beer volatile compounds in a mixed culture.