Since 2009, Japan’s leading soy sauce makers have considered Keiko Kuroshima an authority on their product. Known as a “soy sauce sommelier”, Kuroshima’s mission in life is to create more awareness for this ubiquitous but often overlooked seasoning.
It’s therefore apt that the 35-year-old is based in Shodoshima, an island located about five hours from Hiroshima and long associated with high-quality soy sauce production. Here, Kuroshima explains the source of her passion and why Japanese soy sauce is still so misunderstood by chefs and households alike. Here she discusses how she came to this career and what it entails.
There are only three soy sauce sommeliers in the world and I’m the only woman. After studying art at university, I came across a book by [Muji art director] Kenya Hara that changed my life. In the book, Hara wrote that true expression only comes from something you cultivate yourself. As a result, I reacquainted myself with my hometown, Shodoshima. The more I discovered, the more I found myself looking deeper into the island’s culture of soy sauce production.
Today, 20 to 30% of Japanese soy sauce is still fermented in traditional wooden vats from Shodoshima. In Japan, many industries have turned to mechanisation but a number of traditional soy sauce makers continue to produce soy sauce the old fashioned way.
I was flabbergasted when traditional makers told me their soy sauces weren’t selling and they had no one to carry on the business. But I soon realised that people rarely make a conscious choice when buying soy sauce, even in Japan. Most people don’t know the different types or how to use them. That’s when I decided to become an expert and impart that knowledge to as many people as I can. I want to protect the culture and tradition of Japanese soy sauce.
I honed my tasting skills by joining the inspectors on monthly evaluations on the soy sauce in Shodoshima. I learnt why certain soy sauces can taste good or bad, and why they have different aromas. I began to understand the profound links the soy sauce has to a particular climate, geography and local food culture.
I then travelled around Japan and collected soy sauces from every traditional maker. I only ever talk about a soy sauce [to consumers and chefs] after I have visited the manufacturer, bought the soy sauce, tasted it and used it in my cooking.
I have been known as a sommelier since 2009. I was given the title by Japan’s leading traditional soy sauce makers at a major soy sauce summit.
To use a rich and thick sashimi soy sauce for all fish is a mistake. It works well with fatty tuna, but you have to use a lighter usukuchi soy sauce for more delicate fish like sea bream. If you don’t, the soy sauce will overpower the taste of the fish. I’m always surprised when high-class restaurants give so much care to their ingredients and preparation but end up using the wrong soy sauce.
5 types of Shoyu to know
Shoyu (Japanese soy sauce) goes back to a Chinese variant that arrived in the seventh century and then developed many distinct variants. It uses a koji malt, a blend of soybeans and wheat also found in miso paste and sake, in a special fermentation process.
Made almost entirely from soybeans, this is perfect for people on a gluten-free diet. The increased soybean content means plenty of umami flavours, but it also makes tamari a more acquired taste.
This thick sauce goes well with rich ingredients like fatty tuna or avocado. Try using it instead of brown sauce for tonkatsu (breaded, deep-fried pork cutlet), add it to a curry or even a drop or two to vanilla ice cream!
Shiro is used when you don’t want to change the colour of the dish. With a high wheat content, it is sweeter than other soy sauces and has a distinct aroma of barley miso paste. Good for omelettes, chawanmushi (egg custard) and fresh pickles.
Developed in the 17th century, this variant has a lighter colour, less umami and more subtle aromas. However, it does have a slightly higher salt content. Works well in Japanese dashi (soup stock) and Western dishes like carpaccio or spaghetti aglio e olio.
This accounts for 85% of all soy sauces sold in Japan. It’s well balanced, with the properties of both light and dark soy sauces. According to Kuroshima, most households in Tokyo only have koikuchi in their fridges.
* You can find usukuchi, koikuchi and saishikomi shoyu in the Seto Inland Sea region, but you can only find shiro and tamari shoyu in Aichi Prefecture, near Nagoya.
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This article was originally published in the December 2018 issue of Silkwinds magazine