Closeup of Sake Production: Straining

Greetings Sake Lovers, welcome to another KURAND Magazine article that introduces you to the world of sake.

This is another article in our series taking a closer look at the sake production process. In this article we look at mizukiri (rice straining). Another rather menial sounding task but once again, nothing but could be further from the truth. This is a very important step in the process between shinseki and mushimai (rice steaming).

Sake Making Process in a Nutshell

A very basic diagram of the sake brewing flow can be found in the chart above. This is just a very basic outline. The process varies depending on the variety of rice and the target style of sake.

What is Mizukiri?

Mizukiri is the process of straining excess water from the rice soaked in the previous stage. The final level of moisture in the rice before steaming is extremely important because, as explained in the previous article, it has a bearing on the other stages in the process, in particular the koji (rice malting). Although we will save an in depth explanation about koji for another article, let’s just say that mold needs moisture to grow; too little and the mold grow very little; too much and it grows too much. Even if the moisture level is not exact, it can be adjusted during the steaming — we stress to an extent — but the brewer has to achieve a certain level of accuracy before steaming begins.

The brewer aims for rice which is not too try and not too moist. The final target moisture content before steaming is usually around 30-33% of the initial weight of the rice, although this can vary depending on the style that is being made.

There are four methods to strain the water from the rice.

Four Methods of Mizukiri

Mizukiri Method 1: Straining the water by teburi (swinging by hand)
Some breweries and toji use a different name for this method, but, wrapping the rice in cloth and swinging by hand is the no-fuss, traditional way to strain the water.
■Merit: No expensive equipment required. Water can be strained quickly.
■Demerit: Takes time and skill (If amateurs do it the rice will fly off and not enough water will be strained)

Mizukiri Method 2: Put it into a strainer and leave it
This method is leaving the rice in a strainer and letting it strain naturally.
■Merit: It is easy to do because no extra work it necessary. It also does not require any additional costs.
■Demerit: The amount of water strained from the top and bottom is different (Because water drips down).

Mizukiri Method 3: Suction method
This method is done using a large machine called Woodson to suck the moisture out.
■Merit: Water can be taken out quickly. Work efficiency increases.
■Demerit: :Requires a large amount of capital investment. Moisture is not removed evenly.

Mizukiri Method 4: Centrifugation
This method is using a centrifuge that employs centrifugal force to strain water.
■Merit: Strains water quickly. Water is strained evenly (no unevenness). Work efficiency increases.
■Demerit: Specialized equipment is necessary so requires enormous amount of capital investment (Even more expensive than suction equipment).

Asking Brewers About the Difficulty of Mizukiri

Which mizukiri method do you use?

10kg portions are put into net bags and washed by hand. Following ample soaking, the bags are 30 times from left to right to shake the water out. Some breweries use the dehydrating tub of a washing machine, but we prefer to do it by hand.
(Takizawa san, Takizawa brewery)

My mother is a toji so she does all the seimai, shinseki, and mizukiri herself. To avoid hurting her back, the rice is divided into 5kg portions and put into strainers. This is quite a small volume by industry standards. Mizukiri is done with these strainers. Shaking the rice stops it from sticking together.
(Tanaka-san, Asahiduru)

Even this simple process of straining water is dependent on the type of rice and what time of sake is going to be made! With so much rice to process, there will never really be an easy solution to this seemingly simple task.

Check out the previous articles in this series.

Closeup of Sake Production: Rice Polishing

Closeup of Sake Production: Rice Washing

Closeup of Sake Production: Rice Soaking

So there you have it, nothing in brewing is as easy as it sounds. If you have enjoyed this article and feel ready to embark on a voyage of discovery, why not head on over to Japan, to Tokyo, and visit KURAND where you can taste over 100 different types of sake without time limits at your own leisure. Each sake comes with a story of how it was made and no two sake are made 100% the same way. We look forward to welcoming you very soon!