The Yeast Flora of Apple Juices and Ciders

SUMMARY: The yeast flora of a bulk of apples was followed through the different stages of cider making to the finished product. Yeasts on the fruit, and in the juice from an experimental plant, were mainly asporogenous. In a commercial sized plant, the juice was contaminated with yeasts present on the racks and cloths. Treating the juice with sulphur dioxide improved the yeast flora during fermentation; some controlling factors are considered. The efficiency of centrifugation depended on the pH of the juice, on sulphiting and on the loss of specific gravity that had previously taken place.