What types of yeast are commonly used in Japanese whisky?

When it comes to the yeast used in Japanese whisky, it's actually a fascinating topic and one of the key reasons for their rich and delicate flavors.

Unlike many Scotch distilleries, which typically use one or two highly efficient whisky yeasts with the clear goal of maximizing sugar conversion into alcohol, the Japanese approach is far more "playful." They aren't content with just one type; instead, they employ an "army of yeasts," much like a chef selecting ingredients.

You can understand their yeast usage as primarily falling into two major categories:

Category 1: The Main Force - Professional Whisky Yeast (also known as Distiller's Yeast)

This is the most fundamental and core yeast. Its characteristic is being "hardworking," with strong fermentation capabilities, consistently producing high alcohol yields. You can imagine it as a diligent worker whose main task is to ensure production, solidly converting the sugars in the wort into alcohol. This forms the foundation of the whisky.

Category 2: The Flavor Specialists - Various Yeasts that Bring Special Flavors

This is the essence and secret weapon of Japanese whisky. In addition to the "main force" mentioned above, they also use many other yeasts simultaneously. These yeasts might not be as efficient in producing alcohol, but during fermentation, they generate a variety of wonderful aroma molecules.

Common "flavor troops" include:

• Beer Yeast (Ale Yeast/Lager Yeast): For instance, some yeasts used in brewing ale can impart distinct fruity esters to the whisky, such as notes of banana, apple, or pear.
• Sake Yeast: This is where the most unique Japanese characteristic comes in! Think about premium Ginjo and Daiginjo sake – don't they have those very distinctive melon, fruit, and floral aromas (what we often call "Ginjo-ka")? The Japanese have adopted these yeasts to "graft" those delicate, elegant, and fresh aromas into their whiskies.
• Wine Yeast: Some distilleries even experiment with certain wine yeasts to explore even more complex flavors.

How do they specifically operate?

Large Japanese distilleries, such as Suntory and Nikka, don't simply mix these yeasts together. Instead, they use different yeasts in different fermentation tanks for the same batch of wort.

For example, imagine they have 10 fermentation tanks:

• 5 of them use Type A whisky yeast, yielding a clean, high-alcohol spirit.
• Another 3 use Type B ale yeast, resulting in a spirit full of vibrant fruity aromas.
• The final 2 use Type C sake yeast, producing a spirit with elegant floral and fruity notes.

After fermentation, they obtain several "semi-finished new make spirits" with completely different flavor profiles. Finally, the Master Blender, like a painter mixing colors, blends these different new make spirits in various proportions to ultimately create a whisky with an incredibly complex, yet very balanced and harmonious flavor profile.

So, in summary, there isn't one fixed "standard answer" for the yeast used in Japanese whisky. Their secret lies precisely in this "unconventional" combination strategy, using a combination of various yeasts to craft the flavors they desire. This is why you can always discover various surprises when tasting different Japanese whiskies.