[About Polishing ratio]
Rice is generally polished to around 90% for food use, but for sake brewing it is polished to around 70% or less.Polishing ratio is a value that indicates the percentage of polished rice when the original rice (brown rice) is set at 100.
Thus, a milling ratio of 40% means that 60% of the rice has been polished.
The smaller the value, the more polished the rice is, with ginjo-shu having a milling ratio of 60% or less and daiginjo-shu having a milling ratio of 50% or less.
The reason for polishing is that the surface layer of the rice contains many important nutrients such as protein, fat and starch, and these nutrients can lead to a cloying taste and muffle the sake's aroma.
Generally speaking, sake with a lower rice polishing ratio is said to have a more floral and aromatic flavour.
However, while too many nutrients on the surface layer can be a source of miscellaneous flavour, they can also be a source of umami in the right amounts.
Daiginjo-shu with a rice polishing ratio of 50% or less is sake with an emphasis on noble aroma rather than richness of flavour.
Junmai sake with a rice milling ratio of 70% has a less intense aroma and is more characterised by the umami and richness of the rice, while junmai ginjo with a rice milling ratio of 60% can be said to be a well-balanced sake.
It is important to understand that different rice polishing ratios produce different aromas and flavours, and it is up to the individual to decide which brand he or she prefers.
We encourage you to try sake with different rice polishing ratios and find your favourite one.