Mercedes Fabiana Vargas Perucca

The pursuit of unique flavors in craft beer has led to the exploration of non-Saccharomyces (NS) yeasts. While Saccharomyces species dominate beer fermentation, NS yeasts offer flavor diversification. However, their lower fermentation efficiency and ethanol sensitivity limit their use. This study evaluated 50 NS yeast strains from Argentina’s Cuyo wine region. Torulaspora delbrueckii was selected for sequential fermentations with Saccharomyces cerevisiae due to its promising fermentative and physiological characteristics. Sequential inoculation resulted in a significant increase in fruity and spicy aromas, particularly esters like isoamyl acetate, ethyl hexanoate, and ethyl octanoate, as well as terpenes like limonene and linalool. Sensory analysis revealed that beers produced with T. delbrueckii were characterized by a more complex aroma profile, with significant increases in fruity, floral, and herbaceous notes. Additionally, the sequential fermentation strategy resulted in a higher apparent attenuation compared to pure T. delbrueckii fermentation, indicating improved sugar utilization. These findings highlight the potential of NS yeasts to enhance beer sensory characteristics. Combining NS yeasts with traditional Saccharomyces strains creates beers with distinctive flavors, expanding brewing possibilities. Sequential inoculation strategies offer a viable approach to harnessing the benefits of NS yeasts while ensuring fermentation. This research demonstrates the potential of NS yeasts to enrich the sensory experience of drinking craft beer, paving the way for further innovation in the brewing industry.

Yeasts play a crucial role in the winemaking process contributing to the typicity and originality of wines in a region. Therefore, the aim of the present study was to isolate, characterize, and select yeasts from the Geographical Indication “Pozo de Los Algarrobos”, San Juan, Argentina. Yeasts were directly isolated from grapes and at different stages of spontaneous fermentations of Vitis vinifera Viognier and Chardonnay varieties. Molecular and intraspecific identification of Saccharomyces cerevisiae yeasts was conducted using the D1/D2 domain and interdelta, respectively, observing 13 different yeast strains from Viognier and 12 from Chardonnay vinifications. Based on the enological traits assayed, two strains, V22 (Viognier) and C14 (Chardonnay), were selected for further studies. Microvinifications with these yeasts were carried out with Viognier and Chardonnay grape must in 2 L flasks, and the resulting wines were analytically and sensorially evaluated. Overall, strain V22 produced wines with positive and particular sensory properties, associated with fruity and floral aromas, color intensity, sweetness, aromatic persistence, and varietal typicity. Consequently, biomass propagation of V22 was conducted to inoculate pilot- (100 L) and industrial (12,000 L)-scale fermentations. V22 resulted in a correct wine fermentation performance obtaining a final product with distinctive and genuine properties.