Comparison Test of The Compressed Yeasts for Sake-Brewing

Abstract

The authors examined practical characters of the compressed yeasts for sake brewing made by several factories.
1. Some differences were observed among the compressed yeasts, in the color, the relative hardness, water content and the number of yeast cells per gram.
2. In the early period, the compressed yeasts of low water contents showed low staining ratio, but as time passes, all of them increased theirstaining ratio. The higher the staining ratio is, the slower the growth and the beginning of fermentation are.
3. These were remarkable differences among the compressed yeasts in the contamination of bacteria. As time passes, the contamination was increased in greater part of the compressed yeasts, but some were not.
4. In the majority of compressed yeasts, their growth and fermentation were influenced only a little by contamination. Some of them, however, were influenced very much, so that their growth and fermentation were stopped at last. Therefore much precautions must be taken in using these types of yeasts.
5. From these results, it is recomendoble that the compressed yeasts are used as quickly as possible (within 7 days), ofter they are manufactured, even if the yeasts are stored at low temperature.