2. By the early 1970s it had become a common apply to add pure culture strains of yeasts ( Saccharomyces rouxii and sometimes Torulopsis spp .) and amino acids supplier bacteria to the moromi mash to speed up the fermentation and enhance the shoyu quality. In 1975 major manufacturers started to omit chemical preservatives and add a small quantity (0.5-1%) of alcohol (ethanol; the same as found in wine or beer) to lift the full alcohol content over 2.5%. Some makers bottled the shoyu aseptically to avoid the usage of even alcohol.