Sake Brewing

Hi everyone!

Last weekend, I took a trip to a town called Itayanagi near Hirosaki to volunteer at a sake brewery. Japanese 酒, referred to in Japan as 日本酒 (nihonshu), is commonly called "sake" in Western countries (which technically only means "alcohol"). It is made from rice.

The brewery is family owned, and their top-shelf sake is made almost entirely by hand. We assisted in the process of making this upper grade sake.

The brewery: Iwaki Masamune

The first step in making sake is procuring and polishing the rice. The rice used to make sake differs from your common table rice in that it is more substantial and chewy, and has a more savory flavor. It's also quite a bit more expensive. For different types of sake, the rice is polished to varying degrees. The rice we used for the high grade sake had a whopping 55% of the grain polished away, ensuring that only the starchiest central portions of the rice remained.

After polishing and washing the rice, it is then steamed in giant bins. After the rice is steamed, it must then be laid out to cool down to about 7-8 degrees C. This is the part of the process where we volunteers came in. We were all wearing winter gear despite being indoors, but keep in mind that the brewery was kept at a temperature equal to that outside. My estimate is that it was between -3 and -5 degrees C.

Steaming the rice.

Laying the hot rice out to cool.

Me spreading the rice out, and Tossy being a creeper.

Before I continue, I should mention the most important part about sake brewing: microbes. Like all fermentation processes, sake brewing relies on microbes to convert the starch in the rice into sugars, and then convert the sugars into alcohol. I can't describe it very well, so I'll let Moyashimon do it for me.

醸すぞ！ Let's brew!

Moyashimon is one my favorite anime, and it deals with all kinds of fermented food, displaying the associated microbes as cute cartoon characters. The yellow guys in the back are oryzae, responsible for saccharification (or converting starches to sugars). The white buddies in front are cerevisiae, resposible for alcoholic fermentation (or converting sugars to alcohol). In other alcoholic drinks, such as beer, saccharification takes place first (making wort), and then alcoholic fermentation is performed (making mash). For sake, saccharification and alcoholic fermentation occur simultaneously in the same vat, which is why both microbial buddies are swimming around together in the picture.

To get the necessary microbes into the sake, the brew-masters must culture them in the form of "koji". Before the fermentation process even begins, some of the steamed rice is taken to the koji growing room. This room's climate is highly controlled, with lots of temperature and humidity monitors. Here, the workers spread the rice, and then sprinkle the microbes in the air via a shaker. After a few days, the surface of the rice is covered in a white fuzzy growth, and the koji is ready. Unfortunately for us, they had used up the last of their koji, so we didn't actually get to see the real thing. Here's what the process would have looked like:

The process.

Ripe koji.

The son brew-master demonstrates the aerial spread of microbes, while Hide freaks out about his asthma.

In the giant 2000 L vats, they combine water, lactic acid, yeast, steamed rice, and koji to make "shubo", the starting material. Then, they go through 3 steps of fermentation, adding new rice and water at every step to make a new mash. The three-step fermentation process is important because, while some microbes are vital for fermentation, other microbes are detrimental. For example, the microbes in natto, bacillus, are harmful to the sake brewing process. The other guys forgot to mention to me that we shouldn't eat natto before going to the brewery, so I had to wear a mask while in the fermentation chamber. The three-step fermentation process helps keep the good microbe count high so they won't be as susceptible to getting beat up by other microbes.

Our part took place at the final (third) step of the fermentation process. After flipping and re-spreading the rice several times, the rice was cool enough to be carried in bundles over to brewing vats. As we dumped the final batch of new rice and water into the final vat of sake, we officially completing this year's sake brewing season.

Carrying in the cooled rice.

Dumping rice into the large vat.

Giving the mixture some agitation.

After mixing the new rice in and agitating it around a bit, the brew-master topped it off with some fresh water and covered the vat with a thin cloth. He then showed us some of the other vats that have been sitting around for a bit longer. These vats were bubbly and topped with foam, emitting a fragrance similar to beer.

That's some foamy foamy shit!

I hear the microbes calling out to me!

After the brew has fermented completely, the mixture will be poured into filter bags and then squeezed under a mechanical press. All that's left is bottling, and voila! High grade sake is complete! Once our batch is finished, there will apparently be a party where we get to taste our creation. Until then, we got a bottle of lower grade (machine-made) sake as consolation.

Thanks for reading, and I hope it was fun and interesting! See you next time!