Freeze-dried S. cerevisiae MERIT.ferm was obtained from Chr.-Han.,
Horsholm, Denmark and propagated in a sterile synthetic medium (2%
w/v glucose, 0.25% w/v yeast extract, 0.25% w/v bacteriological peptone,
0.25% w/v malt extract, pH 5.0). Yeast cultures were then incubated
under static conditions at 25 °C for 48 h and stored in aliquots of 1 mL
at −80 °C for the preparation of fresh juice pre-cultures described
below