A gorgeous, fruity aroma that you can feel when drinking Japanese sake. Isn't it strange how sake can have such a beautiful aroma even though it is made from rice?

In fact, this aroma is mainly produced by yeast, which is essential for alcohol fermentation. Yeast is a microorganism that breaks down sugar into carbon dioxide and alcohol. There are many types of yeast used to make sake, and the aroma and taste of the finished sake will change depending on the type.

The Kyoto Industrial Technology Research Institute has been developing, managing, and distributing sake yeast since the 30s, and has long supported the foundation of sake production in Kyoto. Currently, through the development and branding of ``Kyoto Yeast,'' we are presenting a new style of sake to the nation and the world.

In this article, we interview researchers from the Kyoto City Institute of Industrial Science and Technology about the world of yeast and the appeal of "Kyoto yeast." Let's enjoy sake from a small perspective: yeast!

Kyoto City Industrial Technology Research Institute supports sake brewing in Kyoto

Established in 1916, the Kyoto Industrial Technology Research Institute (hereinafter referred to as the Industrial Technology Research Institute) has the slogan "Expanding knowledge and developing culture" and provides technical support to a wide range of manufacturing companies in Kyoto City, from traditional industries to advanced industries. An institution that conducts. In addition to providing technical guidance, research and development, and testing and analysis for companies, they also carry out a variety of other activities, including training for traditional craft technicians.

Sangiken's involvement in sake production dates back to 1936.

``In 1935, the monthly report of the Kyoto City Industrial Research Institute, one of the predecessors of the Institute of Industrial Science, stated that the work of the fermentation department included research on the quality of sake, analysis of brewing water in the Fushimi area, and research on analytical methods for sake. "It seems that the following year, in 1936, they started giving guidance to sake breweries," says Hirooka.

▲Ao Hirooka Research Director

Seino says that he started working on sake yeast, which continues to this day, right after the end of the war.

``After the end of the war, the trend in Kyoto's sake brewing industry seems to have been to make good sake while maintaining quality rather than making a lot of sake.At that time, sake brewing often failed (rotten). However, one factor was pointed out to be the freshness of the yeast.

▲Researcher Tamami Seino

At that time, yeast brought from Tokyo was used. In response to the need to use highly fresh yeast cultivated locally in Kyoto, Sangiken has begun developing, managing, and distributing sake yeast.

The numerous yeasts and data that have been researched and stored for over half a century are truly an asset. Through repeated selection and analysis from a wide variety of yeasts, the flavor of the sake we enjoy today is created.

▲“Sake yeast” kept in the laboratory

I want you to find your favorite sake from the perspective of “Kyoto yeast”

Currently, Sangiken is distributing five types of sake yeast unique to Kyoto called ``Kyoto yeast.'' The first "Kyoto Koto" appeared in 5. Hirooka says this about the situation at the time.

“After peaking in 1973, the amount of sake shipped and produced decreased.Amidst this, the ginjoshu boom was born, and quality became more important than quantity.In the production of high-quality sake, Yeast plays an important role.When I joined the Institute of Industrial Science and Technology in 1997, we had already begun developing Kyoto yeast, and seven years later, we completed Kyoto Koto. I did.”

Sangiken has since released ``Kyo no Hana'' (2007), ``Kyo no Saki'' (2014), ``Kyo no Koh'' (2017), and ``Kyo no Koi'' (2019). The development of unique aromas and tastes embodies the desire to ``use yeast as an opportunity to find your favorite sake.''

▲Flavor map of “Kyoto Yeast”. It can be seen that each has different characteristics.

Normally, it is said that it takes about 10 years to commercialize yeast from scratch. ``The fact that we already have five types is the result of the accumulation of efforts by our predecessors in the past, and the fact that they have carefully stored them,'' says Hirooka.

Of course, since we are dealing with yeast, which is a microorganism, there are many times when things don't go as planned.

Mr. Seino, who was involved in the development of ``Kyo no Koi,'' says, ``We had a hard time getting the strains we wanted. Working with Mr. Hirooka, we repeated several stages of selection from various yeasts.''

▲Mr. Seino explains about the gas chromatography, a machine that analyzes aroma components.

It also seems difficult because the ultimate goal is to produce sake, which is a luxury item.

``Just because you can produce a 10 aroma doesn't mean you can aim for a 20 or 30 next time.Sake is a luxury item, so it cannot be divided just by the numerical part.The specifications and the human part. It's important to strike a balance,'' says Hirooka.

``Kyoto Yeast'' is not a sake that attracts attention at competitions, but was developed with the aim of creating a flavor that is close to everyday life. These gentle tastes and aromas may end up giving the impression of being ``Kyoto-like.''

▲A bottle containing “Kyoto no Koi”. The white, cloudy substance is yeast.

Sake brands using “Kyoto yeast”

Currently, various sake breweries in Kyoto Prefecture sell various brands using Kyoto yeast. Here, we will introduce brands that use each type of yeast for the first time.

Kyoto Koto: Jurakudai Junmai Ginjo [Sasaki Sake Brewery]

A Junmai Ginjo sake made with Kyoto Koto, which has a characteristic aroma similar to green apples. It is characterized by a mellow, stone-like texture, and can be enjoyed warmed to room temperature.

Click here to purchase alcohol from Sasaki Sake Brewery

Flowers of Kyoto: Tsuzuru Junmai Ginjo [Tsuru Shuzo]

This bottle uses "Kyo no Hana," which has a banana-like scent. You can feel the flavor of the rice well, and at the same time, it has a mild and rich sourness. If you let it age a little, you can enjoy the rounded acidity and flavor.

Click here to purchase sake from Tsuzuru Sake Brewery

Kyo no Saki: Sacred Kyoto Prefecture Celebration Junmai Ginjo Unfiltered Nama Genshu [Yamamoto Honke] *Seasonal/Brewery Limited Release

This bottle uses "Kyo no Saki" which produces a refreshing acid called malic acid. It has a fruity aroma reminiscent of Muscat and a refreshing sour taste. If you cool it down a little, you can enjoy the crisp flavor and sourness.

Kyo no Koh: Eikun Honjozo Kyo no Koh [Saito Sake Brewery]

This bottle uses "Kyo no Awa", which produces a lot of succinic acid, an umami component found in shellfish. This brewed sake has a gentle aroma and taste. You can enjoy the rich flavor when heated to around 1 degrees.

Love in Kyoto: First Sunrise Junmai Daiginjo Unfiltered Raw Sake [Haneda Sake Brewery]

This bottle uses ``Kyo no Koi,'' which produces a refreshing acidity in addition to the scent of green apples and bananas, and is characterized by its vibrant, gorgeous aroma and sweet and sour taste. The flavor is great and can be enjoyed chilled in a wine glass.

Promoting branding to improve awareness of “Kyoto Yeast”

In 2021, Sangiken began its brand strategy as ``Kyoto Yeast'' in earnest.

``There are already precedent cases such as obtaining trademarks in each prefecture and disseminating information through websites.However, the yeast that has been branded based on the concept of 5 types of ``Kyoto Yeast'' rather than individual products. I think it's the only one in the country," says Okita.

``I've been using names such as ``Kyoto Koto'' and ``Kyoto Saki'' for a long time. However, since I branded it as ``Kyoto Yeast,'' I feel like there has been an increase in content related to yeast on social media.Finally. I feel like I'm finally starting to get recognized, and I feel like I've finally made a start."

▲Mikako Okita Researcher

Over the past three years, Sangiken has continued to engage in activities that are more in-depth than a public institution, such as participating in tasting events and posting on social media. Based on this foundation, the company is considering strengthening efforts in collaboration between the public and private sectors, such as listing the yeast used on sake labels.

Mr. Seino also says that he has long-term prospects for further advancing sake yeast.

“We are continuing our research with an eye on six or seven types of yeast, but we are currently considering whether existing yeast can be used as is in other alcoholic beverages.We are also looking into using existing yeast in other fermented foods such as beer, wine, and bread. We are also thinking about developing 'Kyoto Yeast.'

With the spread of Kyoto yeast, the existence of yeast, which has a great influence on the flavor components of sake, will become widely recognized in the not-too-distant future. I would like to pay attention to the trends of Sangiken and Kyoto Yeast, which are expected to continue to be active in various ways in the future.

• ・Local Independent Administrative Agency Kyoto City Industrial Technology Research Institute
• ・Kyoto Research Park Building 91 South Building, 9 Chudoji Awatamachi, Shimogyo-ku, Kyoto City
• ・ Telephone: 075-326-6100
• -Kyoto Yeast Official Homepage

Writer Yuki Arai
From Shiga Prefecture/Sake Master/SAKE DIPLOMA
After working at a liquor store and a food manufacturer, he became a freelance writer. Her favorite type of sake is a rich type that allows you to enjoy the flavor of rice. Her hobbies include drinking, cooking, and traveling.