Novel starters for old processes: use of Saccharomyces cerevisiae strains isolated from artisanal sourdough for craft beer production at a brewery scale

The deliberate inoculation of yeast strains isolated
from food matrices such as wine or bread, could allow
the transfer of novel properties to beer. In this work, the
feasibility of the use of baker’s yeast strains as starters for
craft beer production has been evaluated at laboratory and
brewery scale. Nine out of 12 Saccharomyces cerevisiae
strains isolated from artisanal sourdoughs metabolized 2 %
maltose, glucose and trehalose and showed growth rates
and cell populations higher than those of the brewer’s strain
Safbrew-S33. Analysis of allelic variation at 12 microsatellite
loci clustered seven baker’s strains and Safbrew-S33
in the main group of bread isolates. Chemical analyses of
beers produced at a brewery scale showed significant differences
among the beers produced with the baker’s strain
S38 or Safbrew-S33, while no significant differences were
observed when S38 or the brewer’s strain Safbrew-F2
was used for re-fermentation. The sensory profile of beers
obtained with S38 or the brewer’s yeasts did not show significant
differences, thus suggesting that baker’s strains of
S. cerevisiae could represent a reservoir of biodiversity for
the selection of starter strains for craft beer production.