Brewing Characteristics of the Maltotriose-Positive Yeast Zygotorulaspora florentina Isolated from Oak

Abstract

The use of wild yeasts in fermentation is becoming a viable option for the differentiation of beers. To achieve good fermentation rates and alcohol yields, however, such yeasts must have the ability to utilize the wort sugars maltose and maltotriose, a relatively rare trait amongst non-domesticated yeasts. Zygotorulaspora florentina is a species with the ability to utilize both sugars, and was evaluated here with respect to its brewing potential. The strain studied (VTT C-201041) was isolated from bark of an oak tree (Quercus robur) in Espoo, Finland. The fermentation performance of the strain was compared to that of two ale yeasts as well as the species type strain (VTT C-94199). Both Z. florentina strains fermented wort efficiently (apparent attenuation levels >77%). While the type strain had the highest yield, the Finnish strain produced more volatile aroma compounds. The species is capable of decarboxylating ferulic acid to produce the spice/clove-like compound 4-vinylguaiacol, which was present in beers at a concentration above the typical flavor threshold. The characteristic flavor of 4-vinylguaiacol was not however perceptible in taste trials, possibly due to the masking effect of other compounds. The potential of this species for industrial application is discussed, particularly in relation to its apparent ethanol sensitivity.

Beer fermentation performance and sugar uptake of Saccharomycopsis fibuligera–A novel option for low-alcohol beer

“…In this study, the fermentation period was chosen for 20 days in order to bridge a potential prolonged lag phase. Even though such a lag phase was observed in previous studies during the fermentation of wild Saccharomyces yeasts (Nikulin et al, 2020;Hutzler et al, 2021) it should not be generally excluded for non-Saccharomyces yeasts. While it cannot be completely excluded that the lag phase would have reverted to the active phase at a later stage, based on the extensive stagnation of the fermentation, it could be assumed that there was no delay in fermentation.…”

Beyond Saccharomyces pastorianus for modern lager brews: Exploring non-cerevisiae Saccharomyces hybrids with heterotic maltotriose consumption and novel aroma profile

“…The ability to utilize maltotriose is typically associated with ale S. cerevisiae and S. pastorianus strains, while limited utilization is seen throughout non-domesticated yeast species ( Methner et al, 2019 ; Nikulin et al, 2020a ). Nevertheless, relatively few yeast strains have been tested for this phenotype due to lack of appropriate screening tools and the high cost of the oligosaccharide in its pure form.…”

“…Alongside the potential benefits for aroma complexity, there are a few typical traits in wild yeasts that are regarded undesired in lager brewing. These include the production of phenolic off-flavors such as 4-vinyl guaiacol (4-VG; Gallone et al, 2016 ), lack of cold tolerance ( Nikulin et al, 2018 ), suboptimal flocculation ( Hutzler et al, 2021 ), and most importantly, inefficient fermentation of the most abundant sugars in brewer’s wort, maltose and maltotriose ( Steensels and Verstrepen, 2014 ; Methner et al, 2019 ; Nikulin et al, 2020a ). Maltotriose is typically utilized at the end of the fermentation ( Dietvorst et al, 2005 ).…”

Sourdough Yeast Strains Exhibit Thermal Tolerance, High Fermentative Performance, and a Distinctive Aromatic Profile in Beer Wort

“…Maltotriose utilization has been considered a trait shared between bakery and brewing yeast strains, acquired during their interaction with humans [44], although its uptake varies largely between strains [20]. Traditionally, the maltotriose-positive phenotype has been considered beneficial as its residual concentration in beer correlates inversely with the alcohol yield [20,45,46]. Nevertheless, the consumer demand for low-alcohol and nonalcohol beers is constantly increasing [47].…”

“…To this end, we analysed t centrations of glucose, fructose, maltose, and maltotriose in the wort before the conclu the fermentation period. Wort samples were taken at 48 and 72 h after the onset of fer phenotype has been considered beneficial as its residual concentration in beer correlates inversely with the alcohol yield [20,45,46]. Nevertheless, the consumer demand for low-alcohol and non-alcohol beers is constantly increasing [47].…”