8D Yeasts and Wine Flavour 361
Ta b l e 8 D. 7General properties of Saccharomycesspecies cerevisiae, bayanus/uvarum and
paradoxusa
Saccharomyces Saccharomyces Saccharomyces
Property cerevisiae bayanus/uvarum paradoxus
Fermentation 10–35 6–30 6–30
temperature (◦C)
Optimum growth > 30 25–30 25–30
temperature (◦C) ‘Mesophilic’ Often ‘cryotolerant’ Undefined
Formation of:
Acetic acid Low – high Low Low – moderate
Ethanol Wide range <S. cerevisiae ≤S. cerevisiae
Glycerol Wide range >S. cerevisiae >S. cerevisiae
Malic acid Neutral/degrade Neutral/produce Neutral/degrade
Succinic acid Low – medium Medium – high Medium
aReferences: Feuillat et al. (1997); Orlic et al. (2007)
when determined (Table 8D.7). ThoseSaccharomycesspecies of active interest are
bayanus/uvarum, paradoxus, cariocanus,andkudriavzeviiand various interspecific
hybrids withcerevisiae(see for example Antonelli et al. 1999; Bellon et al. 2008;
Dubourdieu et al. 2006; Eglinton et al. 2005; Gonz ́alez et al. 2007; Henschke 2007;
Lopandic et al. 2007; Masneuf et al. 2002; Orlic et al. 2007).
8D.6.2.1 Major Compounds
Saccharomycesspecies can modulate all the majorconstituents of wine, includ-
ing residual sugar, ethanol, polyols, acids and phenolics (Table 8D.8). These com-
pounds are essential to the flavour balance of wine by providing sweetness, sour-
ness, astringency, and sometimes bitterness, an undesirable flavour in wine. The
major emphasis on strain selection is to ensure that strains have a high capacity
to produce low residual sugar, less than perceptible (<4 g/L) and often less than
0.5 g/L, for wines made from high maturity grapes, and for wines intended for
maturation under conditions of increased risk to microbial spoilage, such as pro-
longed storage in wooden barrels. A strong demand for selectingSaccharomyces
strains with lowered efficiency in the conversion of sugar to ethanol has arisen in
Ta b l e 8 D. 8Major compounds in wine affected by yeast
Wine sensory Concentration range
Compound class characteristics in dry wines
Residual sugar Sweetness Variable
Ethanol Sweetness, ‘hotness’ 8–>16 vol.%
Polyols Sweetness 4–14 g/L
Acids Sourness 5–9 g/L
Phenolics Colour, astringency, bitterness 0.2–2 g/L