The diversity of microflora in cider production and methods for identifying Saccharomyces and non-Saccharomyces yeasts: A review

Recently, yeasts of the genus Saccharomyces have been increasingly used to make ciders. However, spontaneous microflora has been traditionally used to bring out unique sensory characteristics determined by the terroir. Although the use of Saccharomyces has been extensively studied, there has been little research into use of natural microflora (bacteria and fungi, including yeasts) of apple must in Russian cider production. Therefore, we aimed to analyze the diversity, role, and metabolic products of microorganisms involved in various biochemical processes during cider production, as well as to review the methods for identifying Saccharomyces and non-Saccharomyces yeasts. We reviewed scientific papers published in 2001–2026 and studying microbial communities involved in cider production, as well as methods for their isolation and identification. The publications were sourced from the bibliographic databases of Scopus, PubMed, Elsevier Science, ResearchGate, Google Scholar, and eLIBRARY.RU. The data were analyzed, summarized, and systematized. Ciders with the most complex and harmonious sensory characteristics are produced by mixed fermentation using non-Saccharomyces and Saccharomyces yeasts. The most commonly methods used for microorganism identification are polymerase chain reaction and high-throughput sequencing. The diversity of natural microflora depends on many factors, including the geographic location (terroir) of cider production. Further research is needed to identify which Saccharomyces species and non-Saccharomyces genera predominate in the natural microflora of apple fruits used for cider production in Russia. Also, we need to improve the existing methods, or develop new techniques, for identifying microflora and assessing its effect on the quality of the beverage as early as during fermentation.