Rice, Rice Baby
Did you know that rice used to be served as currency in Japan? Or that even today, the word for rice, 'Gohan,' is interchangeably used to describe a whole meal? Clearly, rice has been an indispensable part of Japanese culture throughout history.
Rice is also an important topic when discussing sake, as it is the primary raw ingredient in sake production and is probably the biggest contributor to the final flavour profile of sake.
Both normal table rice and sake-specific rice can be utilised in sake production. The latter constitutes only about 1% of Japan's total rice production and is a category of rice that must undergo rigorous inspection and meet certain criteria to be officially designated for sake brewing. While table rice is commonly employed for table sake due to its affordability, sake-specific rice, despite its higher cost, is preferred for crafting premium sake. Engineered to facilitate sake brewing, sake-specific rice has its proteins, lipids, vitamins, and minerals concentrated in the outer layers surrounding a starch-rich centre. Considering that the proteins, lipids, vitamins, and minerals in rice contribute to the umami and earthy flavours in sake, while the starch core imparts a floral and fruit-forward character, sake-specific rice plays a crucial role for brewers as they leverage this composition to influence the aroma and flavour profiles of the sake they produce.
For those progressing in their sake journey, you may have encountered the term "Rice Polishing Ratio." This ratio indicates how much each grain of rice has been polished or milled down compared to its original size. Simply by knowing the rice polishing ratio, which is found on the back label of premium sake bottles, you can gain insight into the sake's style.
Yet don’t be surprised if you find exceptions to this rule, as there are many other tricks up the sleeves of sake brewers to impact the character of the final product, like the type of yeast they use, to temperature control, to whether the sake is pasteurised or not, matured in bottle, etc. Thus, it is very possible for a brewer to make two completely different styles of sake from rice made with the same rice polishing ratio. With that being said, generally, you can assume that if you come across a sake with a rice polishing ratio of 70% (so only 30% of the outer layers have been shaved off), it will be a more rustic and rice-forward style of sake compared to another sake with a rice polishing ratio of 30% which will probably be more elegant, lean, and aromatic sake.
The choice of sake-specific rice can also impact the final flavour profile of sake. Currently, there are just over 120 varietals of sake-specific rice, with new strains continually being cultivated. Some of the most renowned varietals include Yamadanishiki, often referred to as the "king of sake-specific rice," as well as Gohyakumangoku, Miyamanishiki, and Omachi. Each of these varietals is typically associated with specific regions, such as Yamadanishiki in Hyogo prefecture or Omachi rice in Okayama prefecture. This regional association is due to the varying climate and soil conditions required for optimal growth of each variety.
Now, unlike wine, where the variety of the grape directly impacts the final flavour, the variety of sake-specific rice does not have such a strong correlation. Instead, which sake-specific rice a brewer chooses is crucial in determining how it impacts the other ingredients used during the sake brewing process. Factors such as how much the grains of rice absorb moisture from water, its compatibility with koji mould (another key ingredient in sake brewing), and its interaction with various types of yeast all vary amongst different varietals. These considerations outweigh the varietal's inherent flavour. So, when we mentioned earlier that Yamadanishiki is known as the king of sake-specific rice, it's because of this rice varietal's exceptional ability to harmonise with other main ingredients.
To conclude, while there are countless factors that determine how a sake will turn out, the type of rice used and how much the grains of rice are milled or polished away before the brewing process are probably the most important factors in determining the final flavour profile of sake!
