If you’ve been keeping up, we took a bit of a general dive into soy sauce, plus types of Chinese soy sauce in a recent post. Now it’s time to look at other national styles of soy, remembering that it’s always best to use soy sauces from the same cuisine as the dish you’re cooking and eating. That’s because, as we discovered last time, soy sauce is not a monolith, with different tastes, colours, flavours and even textural characteristics across national styles, making the use of the correct one important. So… let’s not muck around. Off we go – this time to Korea and Japan!

Korean soy is saltier and not as sweet as Chinese soy. There’s every possibility that Koreans developed soy sauce independently of their Chinese near-neighbours; soy sauce has been produced in Korea for at least 2,000 years. Today it, along with gochujang (a sweetish, fermented chilli paste) and gochugaru (chilli powder) are foundational elements of Korean seasoning.

There are two main categories of soy sauce in Korea. The first is ganjang (간장) or ‘regular’ soy sauce. It’s also called whe-ganjang (왜간장), the ‘whe’ (왜) part denoting Japan, as this style was adopted from Japan in the 1880s. It’s naturally sweeter than guk-ganjang (the second main type), and is a darker black. It’s used for all purpose cooking – eg in stir-frying, braising, marinating, grilling – as well as a dipping sauce. Yanjo-ganjang (양조간장) is higher grade ganjang that's naturally brewed, taking 6 months to a year to ferment. Because of the time it takes to make, it’s more expensive than regular gangjang. Jin-ganjang (진간장), or ‘mixed’ soy sauce’, is made by mixing regular soy with artificially-produced acid hydrolized soy sauce to make a lower grade, cheaper alternative. Some Koreans will reach for this for braises and marinades, saving their yanjo-ganjang for dipping, so its purer, more refined flavours are best appreciated. 

The second main type of soy sauce is lighter coloured guk-ganjang (국간장), or ‘soup soy sauce.’ It is also called joseon-ganjang after the Joseon dynasty (1392-1897). Used to season soups and namul (나물 vegetable side dishes and salads), it has a rich but clean, salty flavour and is lighter brown in colour (although it does darken the longer it ferments, which varies from a few months all the way up to 5 years). This type of soy sauce is the direct by-product of doenjang (된장) production, a fermented soy bean paste not unlike miso. Made using fermented soybeans and brine, traditionally households made their own doenjang, so they always had their own guk-ganjang on hand. In the past all the soy sauce in Korea was guk-ganjang but today Koreans use both the main types.

The two main commercial brands of Korean soy sauce are Sempyo and Chung Jung One. When buying regular soy, opt for yangjo-gajang, reading the back for the ‘TN' number. This stands for Total Nitrogen and indicates the amount of soybean protein present; soybeans release more protein (in the form of nitrogen) as they ferment. The higher the TN number, the more soybean protein it contains and the better the sauce. 1% is average, 1.3% is premium while 1.5% - 1.8% indicates super-premium. Either Sempyo Naturally Brewed Soy Sauce 501S or 701S (샘표 양조간장 501S/701S) are good choices. Also scan the label for any additives such as synthetic preservatives, caramel and corn syrup and, obv, run from those. Commercial guk-ganjing is held to be inferior to home made (and to the artisanal brands you can buy in Korea). Ask at a Korean grocer which of theirs they recommended. 

And now to Japan. Japanese soy sauces are similar to Chinese ones except they’re traditionally made using an even ratio of soybeans and wheat, resulting in a slightly sweeter soy sauce. In Japan, the word ‘shoyu’(醤油 ) is a broad term for soy sauces made from fermented soy beans, wheat, salt and water; varying levels of these make different styles of Japanese soy. Kikkoman makes the best-selling shoyu in the world. The basic method of making it combines roast wheat and steamed soy beans with a fermenting agent (a mould called ‘koji’), then placing this in fermenting barrels with brine to make a solution called ‘moromi’. Left for 6-8 months to ferment, the mixture is then pressed, the liquid pasteurised, aged, then bottled. 

As in China, the two main types of soy are dark (koikuchi 濃い口) and light (usukuchi 淡口) shoyu. Accounting for around 80% of domestic consumption and made using equal parts soybeans and wheat, dark soy is the most used, both in cooking and as a general condiment. The common Japanese soy sauces, such as Kikkoman All-Purpose Naturally Brewed Soy Sauce, don’t say on the label but they’re typically dark. Usukuchi uses about 10% more salt than dark which slows the fermentation process, resulting in a lighter coloured, saltier soy with less ‘umami’ flavour. Tamari (溜まり) has a distinctly viscous texture, darker colour and a unique fragrance; it’s typically used at the table alongside sushi and sashimi as it’s less salty than other soy sauces. Although it’s also used to give a lovely burnished finish to teriyaki dishes. Made using little or no wheat, it’s favoured by the gluten intolerant. though it should be noted that most wheat gluten is broken down during the fermentation process anyway, so it depends on individual sensitivity. 

Saishikomi (再仕込み) is double-fermented using soy sauce instead of water, and is brewed (often in traditional wooden barrels) for a few years, making it a premium sauce enjoyed for aroma and flavour; tasting deeper, less salty and somewhat sweeter than regular soy, it requires skill and time to make a good saishikomi. Which is best appreciated by serving at the table, with tofu, sashimi or sushi, for example. It does also work well in glazes for yakitori, grilled eel or barbecues. Shiro (白), or ‘white’ soy, is lighter in colour and subtler in flavour than regular shoyu, and is made using a high ratio of wheat to soybeans (about 90%-10%). Japanese chefs favour it for finishing light, clear soups and as a dip for delicate sushi and sashimi; it accounts for not even 1% of gross Japanese production. With a salt content of around 18%, this ‘lighter’ soy is not to be confused with genen (減塩), or reduced-salt soy sauce (around 40% less salt). This is a relatively modern invention aimed at the health conscious.

There are some 1300 soy sauce producers in Japan, with Kikkoman owning around 30% of the market. As well as Kikkoman, who pride themselves on their natural brewing techniques, the other well-known brands are Yamasa and Marukin. Marukin claims to be one of Japan’s largest natural shoyu breweries, while Yamasa also prides itself on using traditional methods and no artificial flavours. The Japanese government has a system of grading quality of soy sauces, based on colour, aroma, roundness of flavour and technical considerations such as amino acid and alcohol content. Special Grade is called tokkyuu (特級), First Grade is ikkyuu (級) and Standard Grade, hyoujun (標準). If you spot ‘yuuki’ on a label, this means the ingredients were grown without chemicals and pesticides, while ‘marudaizu’ means the sauce is made using whole soybeans, resulting in a naturally sweet, fuller bodied and higher quality sauce.