What is primarily responsible for producing the fruity and floral aromas in ginjō styles of sake?

The primary factor responsible for producing the fruity and floral aromas in ginjō styles of sake is the cooler fermentation temperatures. Lower fermentation temperatures are essential for ginjō sake production because they allow yeast to work more slowly and produce a range of aromatic compounds, including esters and higher alcohols that contribute to the delicate and complex aromas characteristic of this style.

In cooler conditions, the fermentation process favors the production of these desirable aromas rather than harsher or more pungent flavors that can arise at higher temperatures. This is particularly important in ginjō sake, where the intention is to highlight its aromatic qualities and provide a more refined tasting experience.

While the quality of the rice used, the age of the sake, and the type of yeast can all play roles in the overall characteristics of sake, the specific fruity and floral aromas typical of ginjō styles are most directly linked to the cooler fermentation process.