Growing up in Australia, I never really stopped to wonder about the origins of Vegemite. I just kept eating it, blissful in my ignorance. So it's understandable that most of the people I've asked in my adopted country of Japan have no idea how they started drinking sake—that long before sake, they drank kuchikamizake, the precursor to their national beverage.
Trying to gain some historical context—and bar cred—I decided to look into how sake originated, which is how I discovered that once upon a time, sake was allegedly made with the spit of virgins.
At some point after rice came to Japan from China around the 3rd century BC, it was discovered that if the rice grains were cooked, chewed up, spat into a tub, and set aside for a few days, the resulting brew had pleasurably intoxicating effects. Kuchikamizake literally means "mouth-chewed sake", and is thought to have been porridge-like and a little sour.
Sake, although called 'rice wine', is not wine at all; it's actually made by a fermentation process similar to beer. Grapes have a high sugar content, so if they're left in a bucket in the sun for awhile, yeast from the atmosphere will convert the sugar into wine. But if you leave rice in a bucket in the sun, the result is nothing more than warm, parched rice. Rice and other grains are largely starch, so a starter (bacteria or fungi) is needed to first break down the starch into sugar to later be converted into alcohol. Before the use of koji mold around the 8th century, the Japanese simply used spit: the amylase enzymes in saliva acted as the starter. (If you chew a savory cracker for a while, you'll notice it becoming sweet. That's the work of analyze breaking down the starch to sugar).
At the time, this practice was trending worldwide; it's more or less just how alcohol was made. South Americans were chewing up and spitting out maize to make chicha and yuca to make masato. Mexicans were doing the same with agave for pulque, and the Chinese chewed millet to make xiǎomǐ jiǔ (millet wine).
The novelty in the Japanese method—there is always a novelty in the Japanese method— is that the Japanese ruling class took some liberties in dictating that the saliva must be that of hot young maidens, giving mouth-chewed sake it's more palatable alias, bijinshu ("beautiful woman sake").
Wanting to road-test my newfound knowledge and hopefully glean some more insights, I stopped at my local tachinomi (stand drink) bar on the way home from work. To my luck, I stood next to a sake otaku who also happened to be a scientist. Once standard platitudes were out of the way, I mentioned my newfound learnings.
The scientist, Inamura-san, a researcher for a pharmaceuticals company, reaffirmed that this was indeed likely, and seemed willing enough to indulge me, so I went on.
"I've been wondering: Why was the chewing done by beautiful women?" He smiled coyly, took a breath and raised an index finger. He seemed born ready for this question.
He pointed to himself and said, "Would you rather sake made by the mouth of an ojisan?" (old man), then pointed at me, "Or bijin?" (beautiful young woman). Neither, actually. Call me a prude, but the prospect of imbibing something that was the product of anyone's fermented spit made me nauseous. But I can appreciate the sentiment.
But it's not just marketing, according to my new friend. There is also a apparently some science involved.
"Have you heard of ojishu?" he asked. "It's the smell of middle and old age." He took a pen and paper out of his bag and proceeded to draw a proportional relationship graph. As people age, their microorganisms change, and these noisome elements can result in a less toothsome brew. The ojishu phenomenon has been identified by Japanese scientists as the result of increase in the concentration of the chemical compound 2-nonenal, which produces an "unpleasant greasy and grassy odor" in people.
At this point, the bar staff brought over two small cups of complimentary sake (turns out the Inamura-san is a regular). It had an unusually tart and complex flavor, and sweet but distinctly funky nose. She told us it was Hanatomoe sake from the Nara prefecture, and was unique as it was made by the process of mizumoto. I had heard of kimoto, where sake is produced by exposing cooked rice to bacteria in the air ( ki). But mizumoto? It's sake produced by mixing cooked rice with a type of water ( mizu) brimming with lactic acid bacteria. The lactic acid of this mizumoto acts as the starter to stimulate the booze-making process.
"So it's kind of like kuchikamizake?" I asked. She looked a little surprised and thought about it for a moment. "Yes, exactly," she said, and I felt as sufficiently close to drinking kuchikamizake as I ever needed to be.