The Thoroughbred of Sake Rice: Koshi-tanrei

Greetings Sake Lovers, and welcome to another KURAND Magazine article that introduces you to the world of sake.

In this article, we look at another variety of rice used to brew sake, discovered very recently in 2004, the thoroughbred, Koshi-tanrei.

Rice for Brewing

Rice is an essential ingredient in brewing sake. Just as grapes are an essential ingredient in making wine. And yet, unlike with wine, very few brewers name their sake after the rice. Some even avoid listing the variety on the label at all. That’s perhaps because, unlike the grapes in winemaking, the rice has a comparatively smaller effect on the end flavor and style. In fact, it is the brewer and their craft that traditionally, has the biggest influence in sake brewing.

Be that as it may, there are bound to be people who want to know what type of rice their sake is made from.

Although ordinary eating rice can be used to make sake, this is not desirable because it contains too much protein, which while great for eating, tends to create off-flavors in sake. It is more common to use a special type of rice cultivated specifically for brewing with less protein and a core which is almost completely starch called a shimpaku, visible with the naked eye as an opaque white dot in the center (or just off-center) of the grain. This rice is called sake rice. There is an even more superior type of sake rice that is perfectly suited for brewing. This is called shuzokotekimai.

Varieties of Shuzokotekimai

In previous articles, we looked at the top 3 varieties of shuzokotekimai: the ‘king of sake rice’, Yamada Nishiki; the Yokozuna of the East, Gohyakumangoku; and Miyama Nishiki; as well as the oldest and only pure breed of shuzokotekimai, Omachi. New varieties of shuzokotekimai are being developed all the time and while there have been many failures, there have also been plenty of successes. One of the more recent successes was developed in Niigata as a potential successor to both Yamada Nishiki and Gohyakumangoku and its name is Koshi-tanrei.

The Story Behind Koshi-tanrei?

The success of Koshi-tanrei is less of a surprise knowing who its parents are: none other than Yamada Nishiki and Gohyakumangoku.

The creators of Koshi-tanrei attest that the aim was never to create a rival to Yamada Nishiki. The prefecture already had its own extremely high-quality sake rice in Gohyakumangoku, which was discovered by the prefecture in 1938 and named in 1958. However, although Gohyakumangoku has been instrumental in engineering Niigata’s signature clean-dry style that is arguably the rice that put the prefecture on the map, it is not without its flaws, namely, its tendency to crack when polished which prevents brewers from polishing it to the same sort of high levels as Yamada Nishiki.

This flaw generally makes it unsuitable for producing the really high-quality daiginjo—although that hasn’t stopped many brewers challenging its limits—it does, however, produce excellent koji.

Yamada Nishiki is also not without its flaws. The grains are very big—they have to be to house that large shimpaku—which makes the ears of the rice top heavy which on long lanky stems are easily blown down by winds. This is a particular problem because the time it takes to achieve ripening often sees its growing season overlap with the typhoon season in Japan. This makes Yamada Nishiki notoriously difficult to cultivate.

To compensate for these flaws, brewers were already mixing Yamada Nishiki and Gohyakumangoku together long before the discovery of Koshi-tanrei.

Koshi-tanrei was not an overnight success though. The joint project between the Niigata Prefecture Sake Research Institute, Niigata Prefecture Sake Brewer’s Association, and Niigata Crop Research Centre took over 15 years. But In 2004, after much trial and error and many failures, all their patience and hard work were finally rewarded.

Why Call it Koshi-tanrei

The rice was christened Koshi-tanrei by the governor at the time, Ikuo Hirayama. Although his thought process behind the naming is unknown, the name was clearly inspired by the prefecture’s famous eating rice Koshi Hikari. Koshi is the old name for a major province in Niigata and pops up a lot in the names of rivers, mountains, towns and sake brands in the prefecture. Tanrei is a Japanese word for Niigata’s signature style. It literally translates to light (as in light body).

Above is a photo of unpolished Koshi-tanrei. The shimpaku (white core) is clearly visible.

A Sake Rice Thoroughbred

Koshi Tanrei is a thoroughbred that has inherited the best of both Yamada Nishiki and Gohyakumangoku and none of their flaws.
It is able to withstand polishing beyond 40% and has good water solubility which means it becomes the correct consistency when steamed, making it perfect for koji, and breaks up in the fermentation at precisely the rate required to impart just the right amount of flavor. Additionally, it has lower protein than its parents giving the final sake a softer more rounded quality.

There had always been a demographic of people that preferred richer sake, that Niigata’s overly light, clean style had been unable to tap into. But having inherited both its parents’ traits, Koshi Tanrei produces a hybrid between rich and light sake that finally matched their preference. And when fermented at lower temperatures, it produces Yamada Nishiki’s trademark mellow bouquet of tropical fruit and flowers, albeit in a much more restrained style—like its other parent Gohyakumangoku.

Back before the discovery of Koshi Tanrei, Niigata sake made with anything other than Yamada Nishiki had struggled to make an impact at the Zenkoku Shinshu Kanpyokai (National New Sake Championships). Niigata did not provide the right climate (warm) for growing Yamada Nishiki which meant that brewers had to purchase from outside the prefecture.

The prefecture was winning awards with Yamada Nishiki purchased from other prefectures, but Niigata, often referred to as the Bordeaux of Japan, had not built its reputation off other prefecture’s rice and wanted to win awards for sake where everything from the raw ingredients (water, rice, and yeast) to the people and skills came from Niigata to celebrate its rich terroir. And to do this they needed to create rice on par with Yamada Nishiki. This was the real motivation behind the development of Koshi Tanrei.

In the year it made its debut into the market, in 2007, 15 breweries from Niigata prefecture submitted sake made with Koshi-tanrei into the competition. Eight brewers took home a prize; five scooped gold.

The number of breweries in Niigata using Koshi-tanrei has risen sharply since.
Many breweries create a version of the same sake using Koshi-tanrei, Yamada Nishiki, and Gohyakumangoku so that you can taste the difference for yourself.

At KURAND SAKE MARKET, we showcase sake from all over Japan produced with different varietals of rice. While we can’t promise you will find Koshi-tanrei, there are plenty of other varieties to try. Why not make a visit to KURAND part of your next trip to Japan. We look forward to welcoming you soon!