Brewer´s spent yeasts for oenology: from characterisation to must fermentation

In order to follow the principles of the circular economy, the spent brewer´s yeasts were in this work evaluated to be considered as a raw material for production of yeast derivatives for oenology. They provide natural source of organic nutrition, improve organoleptic properties and physico-chemical stability of wines. In this work, the spent yeasts from different beer styles were evaluated for their primary characteristics. Three types of yeast derivatives were prepared, inactive yeasts used for active dry yeast rehydration, lysates for organic nitrogen supply during fermentation and yeast hulls for adsorption of fermentation inhibitors. The chemical properties, fermentation kinetics and aromatic compounds formation of spent yeast derivatives were comparable to the well-recognized commercial products. However, the sensory analysis of final wines revealed bread-like and yeast autolysis off-flavors.