[Trivia] What is the ratio of polished rice? I want to know more about the lightly polished sake that we hear about so often these days!
The rice polishing ratio is written on the label of sake. The rice polishing ratio affects the taste of sake and is the standard for distinguishing between daiginjo sake and ginjo sake. Eriko Fujita, a sake sommelier, explains the rice polishing ratio.

What is rice polishing rate?
The polishing ratio is a number that indicates the degree of polishing, or how much the rice has been polished (shaved down). A rice polishing ratio of 60% or less can be called Ginjo sake, and 50% or less can be called Daiginjo sake. In other words, Daiginjo sake is made using rice that is more than half polished.
The rice polishing ratio can be calculated using the following formula.
Rice polishing ratio (%) = weight of polished rice (kg) ÷ weight of brown rice (kg) x 100
By the way, the rice we eat is polished to about 90%. Why does rice used for sake brewing need to be polished to this extent?
Why do we polish rice?
The surface and germ of brown rice contain proteins, lipids, and vitamins, which inhibit the growth of koji mold and yeast, and can cause impurities in the flavor and aroma of sake, so they must be removed.
There are various methods for polishing rice, the most common being spherical polishing, in which the rice is shaved into round beads. In contrast, flat polishing, in which the rice is shaved evenly all over while retaining its long, thin grain shape, is called flat polishing. For the same polishing ratio, flat polishing produces a cleaner flavor than spherical polishing, which removes too much rice. Flat polishing was previously considered difficult, but in recent years advances in rice polishing machines have made it possible.
By the way, even if it is for the purpose of making delicious sake, don't you think it is a waste to shave off so much rice? Don't worry, the surface is used as bran for livestock feed, fertilizer, and pickle beds, and the white part is used as rice flour to make rice crackers, dumplings, rice flour bread, etc., so it is not thrown away.
The boom in lightly polished sake
In fact, delicious sake that is lightly polished has recently become a bit of a trend. Lightly polished means that the rice is polished to 80% or 90%, and sake is brewed with sake rice that retains the parts that were previously considered to be the source of unpleasant flavors. As mentioned above, polishing the rice does not mean that it is all wasted, but it is attracting attention from the perspective of sustainability, as people would like to use it to make sake if possible.
In contrast to the clean taste of ginjo sake made from polished rice, lightly polished sake is characterized by its unique flavor. Of course, there are many that are well-balanced, but there are also sakes that take advantage of the so-called off-flavors to compete with "complex flavors." In any case, it is very difficult to make sake that makes use of elements that have traditionally been considered to be obstacles to brewing, and it is also a testament to the technical capabilities of sake breweries that dare to take on the challenge.
This lightly polished sake allows you to experience the inherent power of rice. Please enjoy its unique flavor, which is different from daiginjo and ginjo sake.
Writer/Sake Master Eriko Fujita
Expand your world to a sake specialty store in Osaka and encounter a variety of sake and sake breweries. Favorite sakes are Akishika, Ohgi, and others.
Other than drinking, my hobbies include collecting minerals and raising swallowtail butterflies.