Joumen kobo (top-fermenting yeast)

Joumen kobo (上面酵母), or top-fermenting yeast, refers to yeast that floats at the surface of the liquid toward the end of fermentation in sake brewing. As fermentation progresses, yeast usually settles within the liquid, but top-fermenting yeast, as the name suggests, tends to remain near the surface. This state involves specific yeast strains (for example, top-fermenting yeast) and can influence the fermentation process and the flavor. Sake made with top-fermenting yeast generally tends to have a rich aroma and a more fruity taste, so brewers are expected to make the most of these characteristics in their sake making.