Specially grown varieties of rice are used for sake brewing because of their unique structure.
Something that you will regularly see when it comes to choosing your sake is the listing of the polishing ratio of the rice. Sake rice is always polished and how much it is polished has been the determining factor in the class of the sake.
So why all the polishing? Sake rice is bigger and more plump, structured to have a very large core of starch with all of the fats and proteins, vitamins and minerals on the outside layers of the rice grain. This allows for polishing off of a lot of the components of a grain of rice which will add weight, richness and sometimes unwanted flavors in a specific style of sake.
Due to the unique structure of a grain of sake rice, brewers are able to better control the type of beverage that their sake turns out to be.
A light bodied, floral and mildly sweet sake will have been made with less of the outer layers, a more polished grain.
A rich, umami laden sake will generally be made with a less polished grain.
A grain of white table rice, the kind that we eat, is generally polished to 90-92% of it’s original state, just enough to take off the brown fibrous husk. No more polishing is necessary.
A grain of sake rice, however, will be polished according to the following classifications:
- A Junmai classification requires a ratio of between 70%-60%. This means that at least 30% of the grain is polished away.
- A Ginjo classification requires 60%-50% remaining grain.
- A Daiginjo classification as stated above requires at least 50% of the grain to be polished away. How low you go is up to the brewer and the equipment he/she has to work with.
At Sakemama, we feature Absolute Zero, by Niizawa Shuzo, which features a shocking .85% polishing ratio, less than 1%
The takeaway here is that by knowing how much the rice used to make a sake has been polished, you will have an indication of its style. More polished rice yields lighter style sake.
Of course there are a myriad of exceptions to this rule as with any sake subject.
Stay tuned for part 2 of the scoop on sake rice.