Isojiman Shuzo is a celebrated brand name in the Japanese sake industry, and it is the pride of the country. The brewery was established in Yaizu City, Shizuoka Prefecture in 1830. The magnificent Shizuoka affords an exquisite environment and excellent water flow for sake brewing. With the fusion of traditional techniques and innovative technology, its production has always been at a supreme level. The consistent style of Isojiman with pleasant aroma and texture is unique for the sake fans, and they can always recognise it. Today, Isojiman has become one of the leaders of the Japanese sake industry. We are delighted to have this interview with the current (8th generation) president of Isojiman Shuzo, Mr. Yohji Teraoka, to talk about the success of the brewery.
WHAT SAKE BREWING PROCESS IS ISOJIMAN PROUD OF?
1) QUALITY OF RICE DETERMINES THE QUALITY OF SAKE
The premium Yamada Nishiki is the solely sake rice we use, which is only available in the Tojo Town of Kato City in Hyogo Prefecture. Yamada Nishiki is classified as the highest quality rice in Japan, known as tokujo-mai (special-excellent-class rice) and tokuto-mai (excellent-class rice). We fully utilise Yamada Nishiki with the best rice polishing technology. After rice is polished, we leave a month to wither the white rice (wither: to remove the water from the rice). Sake brewing begins when we start using the rice. The rice is rinsed with 300 to 400 litres of fresh water in a 10kg colander for the first wash. After the rice is completely washed, it is then soaked in time. The raw material processing determines the taste of the sake. If this process fails, the rest of the procedures could not go well.
2) MAKING KOJI FOR ISOAMYL YEAST
We make Koji for the use in isoamyl acetate yeast. The steamed rice was moved to the koji room. When the temperature is lowered to a certain degree, a single grain of white rice propagates 2 to 3 koji fungus. As the temperature drops very slowly, it takes 60 to 70 hours to complete the production of koji. When the surface turns light green, koji is ready. Koji making requires skilful technique, which is a secret of our brewery.
3) BOTTLING, PASTEURISATION AND UPPER TANK
Fermentation and pressing of “moromi”, speedy filtration and bottling are proceeded efficiently to ensure the freshness of sake. At this time, hiire (pasteurisation) is conducted rapidly to make lose active enzyme and to stabilise sake quality. We took the lead to do this in the Showa 50s (mid-1970s). There were no other sake breweries in Japan that used this advanced sake manufacturing process.
All the above procedures are particularly important. Joso (press separation of sake) and Shibori (pressing) are the most essential ones among all the processes. If the cloth bag used for pasteurisation is dirty or smelly, the previous 40 to 50 days of work will be ruined. Therefore, it is necessary to wash the cloth bags thoroughly. After using the cloth bag in April, it will be soaked in the refrigerated sake and repeatedly washed every day for half a month before it is used again in November. Thus, the original taste of moromi is created.
4）THE EXCELLENT SOFT WATER FROM THE SOUTHERN ALPS
Soft water with a hardness of 45 is the most suitable for making Ginjo. The water we use comes from the Oi River, an underground river from the Ainotake source in the Southern Alps. Since the amount of organic materials contained in soft water is small, the fermentation happens gently, and it is suitable for making Ginjo. We set "Sublime Transparency (a registered trademark)" as our theme to make sake. We pursue for an ultimate balanced and elegant Ginjo sake that Isojiman is proud of. The sake we make has the various taste and aroma derived from the fermented "moromi" itself.
THE SECRET OF MAKING HIGH-QUALITY SAKE
Sake brewing is not easy, and compromise is not allowed. We do not follow the market trends. We keep making products that are consistent with our original intention.
"Our motto for sake brewing is "no relax, no compromise." Except for rice washing, all the procedures are completed by hand without using any machines. We need manpower every year for the laborious process. The quality of rice changes every year, but I am proud of Team Isojiman. Our product style does not change according to any market trends, instead our style remains the same every year. Most of our customers can recognise the difference of taste. If our product style is inconsistent, the customer will be confused when making a purchase."