Yeast Strain and the Formation of Flavour Components in Cider

Two apple juices were fermented at 8°C and 18°C using thirteen strains of Saccharomyces uvarum. Glucose, fructose, malic, lactic, isobutanol, 2–3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined in the two resulting experimental ciders. This data was correlated by means of multiple regression equations derived from earlier work with the following organoleptic characteristics: sweetness, sourness, fruity, scented, sharp and irritating flavours and a “global hedonic score” for overall acceptability. A significant effect of yeast strain could be detected on all component concentrations except ethanol, ethyl acetate, amyl alcohols and titratable acidity. The amounts of malic acid and titratable acidity found in cider depends mainly on the source of the juice. The anticipated effect of the source of the juice on sourness and on sharpness and fruity flavours is therefore significant. Yeast strain is also expected to have a significant effect on fruity and sharp flavours as well as on overall acceptability.