The sake brewing starter is called moto (“source”) or shubo (“mother of sake”) in Japanese. This sake starter, made of water, koji, steamed rice and yeast, is second only to koji quality in determining the quality of the end product.
The purpose of the starter is to cultivate ideal yeasts for the main fermentation. Since heat sterilization is not used for koji, it is essential to reach the dominant condition of yeast as soon as possible to bring the anaerobic conditions that prevent microorganism contamination in the starter.
Before the domination, it is necessary to maintain an acidic environment to prevent contamination. There are two types of sake starter methods: using natural lactic acid, or adding lactic acid.
#1.Ki-moto style (using naturally occurring lactic acid)
#2.Sokujo style(adding lactic acid)
Adding lactic acid during the production process creates “Sokujo-moto” starter.