Microbial Diversity and Flavor Quality of Fermented Beverages

Abstract The enormous varieties of flavor sensations present in fermented beverages occur due to the presence of highly variable concentrations of volatile compounds. Variations can occur between species, in the maturity of the raw material (fruits, stems, or grains; raw or cooked) used, and in the metabolism of microorganisms (yeasts and bacteria) used for the manufacture of the specific beverage. Molecules with important organoleptic properties are usually found in trace amounts in a complex organic mixture, hence there is not a unique valid method of analysis for all compounds. The “value of flavor,” which is the ratio between the concentration of a compound and the threshold of perception, gives an idea of the aromatic potential of each compound. There are different families of compounds that contribute to the flavor of alcoholic beverages including higher alcohols, esters, carbonyls, methanol, terpenes, furans, and miscellaneous compounds (fatty acids, phenols, lactones, sulfur compounds, etc.). This chapter provides an overview of the main production processes and the organoleptic characteristics of the most widely consumed fermented beverages in the world, including wine and tequila. It also discusses the impact of microorganisms that are used as inoculants on the aroma and quality of these beverages.