Lactic acid plays a crucial role in sake brewing. It suppresses the growth of spoilage microbes and undesirable wild yeast, preventing their presence in sake and subsequent quality deterioration. Notably, sake yeast is highly resistant to lactic acid and can coexist with it in the brew. Therefore, lactic acid effectively protects sake from unwanted elements during yeast growth.
The simplest method to obtain the necessary lactic acid for brewing sake is to add lactic acid directly to the water used in sake brewing. By then adding yeast such as Kyokai Kobo, it is possible to brew a clean sake with minimal off-flavors. This method is called Sokujo-moto(速醸酛), and it is said that approximately 90% of the sake on the market is brewed using this method.
On the other hand, there are other methods such as Yamahai(山廃) and Kimoto(生酛). Both of these methods involve brewing sake while waiting for natural lactic acid to enter the water used in sake brewing. Of course, this method takes longer for brewing, and since unexpected bacteria and microbes often enter while waiting for lactic acid to enter, sake with complexity and sometimes off-flavors is brewed. Due to the longer brewing time and the increased uncertainty in the taste of the finished product, this method is adopted only to a small extent, with about 10% of the market believed to be brewed using this method.
Most people who start drinking sake may not like Yamahai or Kimoto sake. However, if you are interested, please try challenging yourself with this type of sake at least once. These methods are based on brewing techniques that have been passed down for centuries, and I think you can feel the complexity and depth of sake flavor.
If you’re interested, I recommend starting with the following sake. For Yamahai(山廃), “Kikuhime Yamahai Junmai” is a masterpiece with complexity that embodies the essence of Yamahai, while for Kimoto(生酛), “Daishichi Junmai Kimoto” is a masterpiece that makes you think, “Can such a beautiful Kimoto exist?”
Yamahai(山廃):
Kikuhime Yamahai Jyunmai (菊姫山廃純米)
Kimoto(生酛):
Daishichi Jyunmai Kimoto (大七純米生酛)