Applications of natural ingredients in alcoholic drinks - Natural Food Additives, Ingredients and Flavourings - page 403

Fig. 16.16 Yeast propagation system at Jennings Brewery, Cockermouth, UK.

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(see Section 16.3.1). Additionally, many drinks are rendered microbiologically dead
by a pasteurisation step prior to or after packaging.
Brewers always have adequate stocks of viable yeast throughout the year,
cropped from previous brews. If the yeast ceases to function properly or if it
becomes contaminated, then brewers can acquire fresh yeast from another similar
brewery or propagate their own (Fig. 16.16) from pure cultures (often of their own
yeast) obtained from state depositories, private non-profi t depositories or specialist
companies (Table 16.23). Similarly, rice winemakers need an all-year-round
supply of nuruk (Korean makkoli), koji (Japanese sake) or similar to provide the
right balance of microorganisms for saccharifi cation/fermentation (McKay et al.
2011b). Makers of cider, perry and wine, on the other hand, tend to use fresh
cultures for each new brew.
Additionally, many winemakers and a few cidermakers add pure cultures of
malolactic bacteria (especially Oenococcus oeni , but sometimes Oenococcus spp.