Yeast Hybrids in Winemaking

Abstract

AIM: There is significant variety in the choice of commercial yeast strains available for wine production. Yeast hybrids represent one class of commercial yeasts. The purpose of this review is to define what yeast hybrids are, how they arise in nature and in the laboratory, and to discuss the features of these yeasts that differentiate them from non-hybrid strains. KEY THEMES IMPACT and SIGNIFICANCE Yeast influence wine aroma and flavor profiles in multiple ways1. In addition to the formation of ethanol, yeast can produce both positive and negative aroma impact compounds directly such as esters, higher alcohols, higher aldehdyes, and sulfur-volatile compounds. Some yeast strains are able to produce factors that enhance mouth feel and many can modify varietal aroma through enzymatic and chemical mechanisms. Yeast mannoproteins and polysaccharides may also affect wine stability. Finally, yeast end-products can alter the wine matrix and therefore the sensory expression of wine characters. Yeast hybrids combine traits of Saccharomyces cerevisiae and other species in this genus thereby expanding the metabolic repertoire of the strain. These yeasts can create novel characters in wine as well as conduct fermentation under non-standard conditions.