The kind of rice used in sake brewing is called ‘shuzou kouteki mai’, or ‘saka mai,’ which means rice well-suited for sake brewing. The grains of that kind of rice are bigger than those of cooking rice, and have a opaque white starchy part called ‘shin paku’ in the center. As this ‘shin paku,’ or the white core, is highly absorbent and easy for ‘koji’ mold to get into, it plays an important part throughout the entire process of brewing. The outer layer of the rice grain contains protein and fat that can cause sake to have an odd taste. This layer is removed by rice milling and only then the ‘shin paku,’ core is revealed. Abundant in rice production, Niigata Prefecture also thrives in the production of rice for sake. Both the former Niigata Prefectural Agriculture Laboratory and the Niigata Prefectural Brewing Laboratory have done research on rice for sake brewing. Taking advantage of the negative quality of soft water in Niigata Prefecture, which is inherently not suitable for sake brewing due to its poor fermentability, a milder ‘tanrei amakuchi’ (clear and dry) type of sake was produced. Behind the scenes, the development of ‘Gohyaku mangoku’ rice for sake brewing was indispensable.
Born at Niigata Prefectural Agricultural Laboratory in 1956 (Showa 32), and developed through cross-fertilization of its mother ‘Kikusui’ and its father ‘Shin 200 go’, the ‘gohyaku mangoku’ rice is synonymous with Niigata. It was named ‘Gohyaku-man goku’ (5 million ‘koku’), since in the same year, the volume of rice production crossed 5,000,000 ‘koku’, (cf. one ‘koku’ or ‘goku’ = 180.39 liters). Because of its qualities, it is easy to make ‘koji’ and it does not melt too much after it is made into ‘moromi’. Once completed, the sake made out of this rice has attractive, clear, dry, and mild flavors. ‘Gohyaku Mangoku’ rice is the very rice that built the foundation for the ‘Tanrei Karakuchi’ (exquisite and dry) quality of sake in Niigata, and is unsurprisingly the most utilized rice in breweries in Niigata Prefecture.
By fusing ‘Gohyaku Mangoku’ with ‘Yamada Nishiki’, a quite popular variety for high-quality sake across the country, ‘Koshi Tanrei’ rice was produced in 2004 (Heisei 16).
Efforts were made to produce sake made out of ingredients solely from Niigata, and as a result ‘Koshi Tanrei’ rice was developed. Initially, it took as long as 15 years to produce ‘Koshi Tanrei’ rice. During this time ‘Yamada Nishiki’ rice from Hyogo Prefecture has been used for producing high-quality sake of the dai-ginjo class. However, ‘Koshi Tanrei’ rice is not easily crushed, even when it is milled heavily but it has a water absorbing quality making it ideal for steaming. Whereas ‘Gohyaku Mangoku’, has a crispy aftertaste along with its rich flavor. Presently, a registration system of producers of ‘Gohyaku Mangoku’ has been started in order to secure a stable supply of this high-quality rice.
Besides ‘Gohyaku Mangoku’, ‘Takane Nishiki’ and ‘Ippon jime’ are also grown in Nagano Prefecture. These three kinds of rice are all used in breweries in Niigata Prefecture. Each brewery has their own unique flavors, which is a result of drawing out of the various features of the rice, resulting in their original brand of sake.