Comparative study of craft beers made different liquid formulation of the yeast Saccharomyces cerevisiae

Abstract

Beer is one of the most consumed alcoholic beverages worldwide. It is a fermented beverage made with natural ingredients such as water, barley, hops, and yeast. Currently, craft brewers are trying to differentiate themselves in the market through innovation, aiming to incorporate liquid yeasts into the brewing process, as these generate a different sensory profile in the final product. The objective of this work was to design two liquid formulations using the yeast Saccharomyces cerevisiae to produce craft beer and verify if sensory changes were achieved. The yeasts used were commercial S. cerevisiae called Safeale-US-05 and native S. cerevisiae isolated from the province of San Luis, called SC-3. Each liquid formulation was designed using beer wort as a culture medium to multiply the yeasts in a bioreactor for 24 hours at 24±2°C, with aeration at 5L/m and agitation speed at 150 rpm. The quality of the formulations was verified under a microscope. To make beer, beer wort was prepared following the recipe for the British Golden Ale style, designed by the Beer Judge Certification Program (BJCP) 2021. The beer wort was placed in two fermenters and inoculated with Formulation 1 (F1-Safeale-US-05) and Formulation 2 (F2-SC-3). After 14 days (7 days of fermentation and 7 days of maturation), the resulting beers were bottled and naturally carbonated. For the sensory study, the beers were evaluated by the brewmaster. The results of the formulation indicated that optimal concentrations for beer production were obtained, F1 (3.8x108 cel/mL) and F2 (1.5x108 cel/mL). Both formulations were of high quality, as they showed 100% viability and no contaminants. The sensory test results indicated that the beer produced by F1 had a bright golden yellow appearance, with low turbidity, while the beer produced by F2 had an amber-yellow color, slightly darker. With respect to the aroma, the beer made with F1 did not exhibit a noticeable hop or malt aroma, whereas F2 had a predominant intense hop aroma. Both beers were within the parameters established for the beer style described by the BJCP. In conclusion, we can say that both formulations are optimal for brewing beer and that the differences observed in each beer are due to the fact that each formulation was designed with two different yeast types. F2, designed with native yeast from the province of San Luis, could be promising for transfer to the craft brewing sector.