Production and characterization of an alcoholic fermented beverage from grape must and beer wort

Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL

In the last few decades both beer and wine world started to innovate themselves, aiming to produce higher quality beverages, this brought life to a virtuous circle in which the consumers are becoming more informed and the producers invest money for the development of high quality and innovative beverages. The main objective of the work was to produce a fermented drink that conjugates beer and wine world. In order to do achieve this goal, we developed, optimized and characterized a fermented drink produced from grape must and beer wort using non-conventional yeast strains. The beer wort is produced with Braumeister (machinery that is able to maintain the temperature stable, thus having a high quality product) from Pilsner malt and blended with equal amount of Grape juice. The fermentation of the mix was performed using two strains of Torulaspora delbrueckii, one isolated from a beer media and one from a wine media, a strain of Brettanomyces bruxellensis and three different strains of S. cerevisiae¸ one used to ferment wine (ISA1000) and the two beer yeast with very opposite characteristics, US-05 is used to ferment ales style and it should be very neutral while WB-06 is used to ferment wheat beer and it gives an estery aroma to the beverage. Fermentation was monitored analysing the difference in the refraction index on the Brix° scale and composition analysed daily by HPLC. In order to choose the most suitable beverage, each drink was analysed by a trained panel aiming to describe the analytic profile of the beverage, and by a non-trained panel aiming to evaluate the degree of preference of these new beverages. Based on a compromise between technological issues and consumers preferences, the best beverage was the one obtained with S.cerevisiae WB-06.