Kimoto-kei, or “kimoto school,” is a traditional sake yeast starter method. Also called sodate moto, it relies on ambient lactic acid bacteria to produce lactic acid. This contrasts with sokujo-moto method, where pure lactic acid is added to the mash.
The lactic acid protects the yeast starter (mash) from spoilage. And it makes an ideal environment for sake brewing yeast to thrive.
A cold temperature is required. And the mash may take 25-30 days to complete.
There are several substyles of kimoto-kei shubo: kimoto and yamahai are the most famous. And according to The Brewing Society of Japan, the ancient bodaimoto method falls into this school.
Kimoto 生酛
Kimoto sake is old-school. It uses the yamaoroshi method to puree the mash. The ten to twelve-hour mixing using paddles is typically divided into three separate intervals. And it’s a lot of work.
But the effort makes sake that is rich, savory, and sour.
Only about 1% of all sake is kimoto.
Learn more about kimoto sake here.
Yamahai 山廃
Yamahai is short for yamaoroshi haishi, or “discontinuation of yamaoroshi process.” This much newer method was developed in 1909.
Yamahai doesn’t use the intense yamaoroshi method. Instead, a slight increase in temperature has a similar effect.
The flavor of yamahai sake is similar to kimoto: rich and earthy with elevated acidity and sweetness.
About 9% of all sake produced is yamahai.
Learn more about yamahai here.
Bodaimoto 菩提酛
Bodaimoto is also called mizumoto 水酛, and it’s likely the first modern sake mash starter. It was developed at the Shoryakuji Buddhist temple in Nara.
The bodaimoto method uses fermented water made of raw and steamed rice. Lactic acid bacteria form naturally. And the water is used in the moto tank.
Bodaimoto predates the kimoto-kei. And there are differing opinions regarding its inclusion as a kimoto-kei method. It develops lactic acid bacteria naturally. But it’s also considered a precursor to modern sokujo-moto methods.
Learn more about bodaimoto sake and some popular brands here.