The fermenting mixture is transferred to brine and the 182 Food processing technology temperature is slowly increased. Acid production by P. soyae lowers the pH to 5.0, and an alcoholic fermentation by S. rouxii takes place. Finally the temperature is gradually returned to 15ºC and the characteristic flavour of soy sauce develops over a period of 6 months to 3 years. The process is described in detail by Fukushima (1985). The liquid fraction is separated, clarified, pasteurised and bottled. The final product is preserved by 2.5% ethanol and 18% salt (Pederson, 1971). Details of the biochemistry of flavour and aroma production are described by Yokotsuka (1960), Yong and Wood (1974) and Wood (1982).