What defines Genshu in terms of sake?

Genshu is defined as undiluted sake, meaning that it has not undergone the process of dilution with water after fermentation, which is typically done to adjust the alcohol level. As a result, genshu retains a higher alcohol content, usually around 18% to 20%, compared to standard sake that is diluted to achieve a lower and more palatable alcohol percentage. This characteristic gives genshu a more intense flavor profile, as the concentration of flavors from the fermentation process is preserved.

The notion of dilution is key in the production of sake, and understanding that genshu stands out for not being diluted helps distinguish it from other types of sake that may have varying alcohol levels adjusted by this process. This is important knowledge for anyone studying advanced sake production and classification.