Two-digit yeast (futaketa kobo)

Two-digit yeasts are those among the yeasts distributed by the Brewing Society of Japan whose numbers have two digits, such as "10," "14," and "18." These yeasts have played an important role in modern sake brewing, and in particular they produce a compound called ethyl caproate. This compound gives the ginjo aroma (ginjo-ka), a fruity, apple-like fragrance, and adds a sense of elegance and brilliance to sake. By adjusting the rice polishing ratio and the fermentation temperature, two-digit yeasts make it possible to brew sake with a wide range of flavors and aromas.