Kimoto and Yamahai sakes can be quite a game changer for people who are only accustomed to drinking sake while eating sushi. These robust, funky brews are definitely worth seeking out, and often make a memorable pairing with smoked meats, cheeses, and even chocolate.
What makes these smoky sakes different from the rest? It all comes down to the yeast starter process.
The yeast starter combines steamed sake rice, koji, water, and cultivated sake yeast in a small tank, to propagate enough yeast cells to transfer to a full fermenting tank. The standard process used for the majority of sakes takes about two weeks total. Since a protective layer of carbon dioxide has not yet been formed on the yeast starter, it's vulnerable to wild yeast and bacteria present in the air. So sake brewers add lactic acid to standard yeast starters in order to kill off the unwanted elements.
For Kimoto and Yamahai sakes, lactic acid is not added as a yeast starter ingredient. For Kimoto, the most ancient and laborious style, the yeast starter begins with only steamed sake rice, koji, and water. By vigorously mashing the ingredients with long poles to introduce oxygen into the yeast starter, the brewers help lactic acid to develop naturally. It takes about two weeks for the lactic acid to kill the wild yeast and bacteria, and then the cultivated sake yeast is added. From this point it takes another two weeks to create enough yeast cells to move on to fermentation, so overall it's about twice as long as the standard yeast starter process.
Eventually, brewers realized that there had to be an easier way to encourage lactic acid development in the yeast starter without all the poking and prodding. It was at this point that yamahai was discovered. Brewers found that when they raised the temperature of the water in the yeast starter, the lactic acid began to develop on its own. The complete yeast starter process still took around four weeks, but was a much less arduous task.
Try Them With Food
Despite the additional labor and time required to brew kimoto and yamahai sakes, a few sake breweries have embraced the style, and the results are delicious, especially when paired with food.
Yamahai and Kimoto sakes generally have more acidity than other sakes, plus they add a smoky sweetness, and vibrant, distinct flavor. Foods that balance savory and sweet pair extremely well with these sakes. Try Chinese sausage, miso glazed pork belly, or Korean fried chicken to start.
Sakes to Look For
Daishichi, a well known brewery in Fukushima prefecture, makes only kimoto styles of sake. Their Minowamon Junmai Daiginjo balances the elegance of daiginjo with the mellow, rich flavors of kimoto.
Kasumi Tsuru, from the Hyogo prefecture, also makes almost all of their sake in yamahai and kimoto styles. Their Yamahai Ginjo is an excellent expression of the style, and is also one of the select sakes to receive a "highly recommended" rating from Wine Spectator.