Snapshots from Japan 3: So-y Many Ways to Soy

Besides matcha, Kyoto is famous for its tofu, which is attributed to its water quality being soft (low concentration of calcium and magnesium). The city is so dedicated to the art and craft of tofu that there are a number of dedicated tofu restaurants serving tofu kaiseiki. I experienced one at Tosuiro, in the atmospheric Pontocho area. It was an eye-opener to see and taste the multifarious forms and ways to prepare tofu!

So(y) inspired, I decide to writeup a comprehensive list of different soy products and different cooking methods to soy in Japan. This post covers the following (click to jump):

Fresh soy products:

Soy milk ramen
Soy milk soft serve
Yuba soy milk skin types – e.g. kumiage, tsumami, hikiage, kanso

Coagulated soy products:

Tofu types – e.g. oboro, kinugoshi, zaru, momen, koyadofu
Aburaage / atsuage
Tofu cooking – yudofu
Tofu cooking – quiche
Tofu cooking – shiratama dango
Okara soy milk residue – e.g. unohana, croquette, donuts

Fermented soy products:

Soy yogurt (bacteria soy milk ferment)
Natto (bacteria whole soy ferment)
Tempeh (fungus whole soy ferment)

Soy-free mimics:

Gomadofu (sesame “tofu”)

Soy milk ramen

Soy milk ramen broth is one of the ingenious use of soy milk in Japan. Normally, a milky, gelatinous broth is made by slow-cooking pork bones for hours to breakdown collagen and fat and draw out umami. To uncover the secrets of vegan ramen, I undertook a cooking class with Washo which I booked through Airbnb Experiences. Washo lets on that to mimic tonkotsu broth without pork, the trick is to use amino acid-rich ingredients, specifically glutamate. Umami taste is potentiated by the combination of glutamate and one of two nucleotides – inosine monophosphate (IMP) or guanosine monophosphate (GMP). IMP is found primarily in meat and fish whereas GMP is more abundant in the mushroom family. In Washo’s vegan ramen broth, he combines kombu, dried shiitake, freeze-thawed mushrooms, miso, shoyu, sake kasu, nerigoma and garlic-shallot oil. Finally, protein-rich soy milk is mixed in, which contributes an unctuous creaminess and rounds off the flavours of the umami dashi base.

Soy milk ramen is now a feature in many vegan cafes across Japan. One of the longstanding and best place to try it is at Towzen, a chef-owned hole-in-the-wall restaurant in the suburbs of North Kyoto. It may take a while to find your way there, but every slurp of the ramen is worth the trip. I had the original Musashi Ramen that came with sauteed nameko, yuba and framed by two cute stalks of mitsuba. The soy milk broth was smooth as silk, rich as butter and packed an intense umami flavour to it. The al dente noodles were the perfect vehicle for slurping up the broth. Typing this is making me hungry.

Soy milk soft serve

Soy milk soft serve combines Japanese technology with soy milk into a swirly delight. Soft serve is ice cream that has more air incorporated, resulting in a softer and lighter mouthfeel. I tried soy milk soft serve as a parfait at Organic Raw8 Cafe in Osaka, as well as in a matcha smoothie in Vegans Cafe, Kyoto. You can’t really go wrong with soft serve since it is made by a machine. But that is also the downside since you cannot make it at home without fancy equipment.

Yuba soy milk skin

Yuba is a non-fermented, protein-rich product made by heating soy milk. The heat-coagulated protein skin that forms on the surface of soy milk is skimmed off, and successive layers are combined to form yuba. There are two theories of how yuba got its name. The first is that the colour and texture of yuba resembles the wrinkled skin of an old woman. So it was called uba meaning old woman, which later was changed to yuba. The second is that yuba is from the surface of soy milk, so it was called uha meaning surface, which later was changed to yuba.

There are four distinctive textures of yuba in traditional Kyoto cuisine, effected based on the precise timing of harvest and level of setness of the soy milk skin. First is kumiage or scooped yuba – so delicate that it can only be eaten with a spoon. Second is tsumami or pinched yuba – this has a little bite between the teeth. Third is hikiage or pulled yuba – which is even more firm. The first three are nama or fresh yuba and have a short-shelf life. Yuba can be dried, which is called kanso yuba, and can come in many shapes: hira or flat, maki or rolled, musubi or knotted.

At Tosuiro, a tofu kaiseki restaurant in Kyoto, I had my first ever experience of kumiage yuba and it was a gustatory revelation. Slippery and soft, it coalesces in the mouth to release the sweet aroma of soy beans. A hint of yuzu citrus to enlivens the dish, but does not detract from the yuba. Soy good at its epitome.

In contrast, the kirikomaki or short-rolled yuba I had at Shigetsu was much more sinewy, an indication that it was likely made from kanso yuba. The yuba was served perched on a reconstitued wheel-shaped gluten cake called kuruma fu in clear osuimono broth.

Tofu

Moving onto the category of coagulated soy products, we have tofu in various forms – kinugoshi, oboro, zaru and momen, just to name the common types. Three types of coagulants that are commonly used in tofu production are salts, acids, and enzymes, used alone or in combination, and each of these coagulants will produce tofu of different flavor and texture. Salt coagulants can be further classified into sulphate-based gypsum (mainly calcium sulphate) and chloride-based nigari (mainly magnesium chloride). Gypsum is the most traditional and widely used coagulant for tofu. It is chosen as a coagulant primarily because it does not mask the taste of the soybeans, allowing premium tofu makers to preserve and highlight the nuanced flavours and aromas inherent in the soy bean. Gypsum yields milder-tasting and more tender tofu than nigari tofu. Traditionally, Chinese tofu makers favoured gypsum while Japanese tofu makers favoured nigari that is extracted from seawater. Acid coagulants include glucono delta-lactone (GDL). GDL is specifically used for silken tofu because it coagulates rapidly to form a homogeneous gel, allowing silken tofu to be made inside the mold without air bubbles. GDL produces tofu with high solid content (10%–13% instead of 5%–10% in regular tofu) and leaves a slight sour taste in the finished product. Hence it is often used in combination with gypsum to produce soft and smooth tofu with little aftertaste. Enzymes such as papain and proteases may also be used as coagulants, but are less common.

Kinugoshi tofu is more commonly known as silken tofu outside of Japan. It is a type of unpressed tofu made by pouring the hot mixture of soy milk and coagulant straight into a mold, where it is allowed to set. Therefore, it has high water content.

Oboro or Yose tofu is the Japanese equivalent of Chinese dou hua, another type of unpressed tofu where the curds are scooped into a mold and allowed to settle before draining off the whey. In Japanese, oboro means cloudy or hazy, referring to cloud-like appearance of lightly curdled soy milk. In Kyoto, oboro tofu is a speciality at Tosuiro, where they prepare and serve yudofu style (see below).

Zaru tofu can be likened to drained oboro tofu. The curds are drained over a bamboo strainer (zaru), so it is denser than oboro tofu.

Momen tofu or cotton tofu is a form of pressed tofu and the most widely used type. The curds are transferred to a mold lined with porous fabric (cotton) and pressed to drain the whey. The result is a firmer tofu with less water content.

Koyadofu is freeze-dried tofu. As its name suggests, koyadofu originated from Mount Koyasan where it was serendipitously discovered by a monk. The process of freeze-drying renders the tofu like a sponge that soaks up whatever liquid it is sitting in. While koyadofu can be found in most Japanese grocery stores, you can also make it by freezing momen tofu and then thawing it. Koyadofu is typically served in miso soup or oden, while not so common uses are as the “bread” in low-carb sandwiches.

Tofu cooking – yudofu (hot water tofu)

Yudofu is a method of cooking, which literally translates as hot water tofu. Traditionally a winter dish, tofu is heated in a warm water bath, ladled out and eaten with soy sauce, grated ginger or scallion. At Tosuiro, their yudofu features their housemade oboro tofu, so you get to kill two birds with one stone – experiencing oboro and the yudofu cooking method at the same time.

Tofu cooking – quiche

Tofu quiche is an egg-free way of enjoying this dish. Quiche seems to be a popular feature in Japanese menus, perhaps because of the French influence. Bland tofu soaks up the flavours of other ingredients used with the quiche, just like how you would make a tofu scramble. I enjoyed the rendition of tofu quiche at Base Island Kitchen, Osaka, which came with broccoli and set in a gluten-free rice crust.

Tofu cooking – shiratama dango

Dango is chewy glutinous rice flour balls. This is not to be confused with mochi, which is made from glutinous rice itself and then pounded. While (silken) tofu is not indispensable to making dango, it is said to improve the texture and make it softer.

Okara soy milk residue

Okara is soy pulp, the residue remaining after soy milk extraction. Okara contains high protein, dietary fibre, most of the soybean isoflavones, and fat-soluble nutritional factors, which include soy lecithin, linoleic acid, linolenic acid, phytosterols, tocopherol, and vitamin D. However okara also contains antinutritional factors, namely trypsin inhibitors (mostly destroyed by cooking), saponins, and soybean agglutinins, which cannot be easily digested.

Okara is mainly used as animal feed in the soybean industry. However home cooks who wish to repurpose okara can use it in both sweet and savoury ways. Unohana is a typical washouku dish that consists of okara cooked with soy sauce, mirin, carrots, burdock root and shiitake mushrooms to a soft and porridge-like consistency. Unohana can be further battered and deep-fried to form korokke, which I thoroughly and surprisingly enjoyed at Kousagisha, Kyoto. Okara donuts are also common in Japan’s traditional arcade markets; I spotted them at Nishiki Market, Kyoto and Higashimuki Market, Nara.

Soy yogurt – bacteria soy milk ferment

Now that we have got soy milk and its products covered, let us move on fermented soy products.

Soy yogurt – like how all things soy in Japan is so good, soy yogurt is no different. This brand only lists soy milk and Lactobacillus spp. bacteria as the ingredients in their yogurt, and none of the nasty thickeners like tapioca starch found on other non-dairy yogurts. The result is a mild, beany yogurt with great texture. If only this could be available in Singapore!

Natto – bacteria whole soy ferment

Natto is made by fermenting soy beans with the bacteria species Bacillus subtilis var. natto, and has got to be the most controversial of all fermented soy products because of its icky sticky slimy texture. When forming natto, the soy beans are first soaked and cooked, inoculated with nattokin (the Japanese name for the bacteria), and allowed to ferment under warm and damp conditions. The bacteria helps us pre-digest the nutrients and antinutrients in soy such that the amount of vitamin B2, B12, E and K increases in natto as compared to unfermented soy. One of the many enzymes secreted by nattokin is nattokinase, which has alterative and anticoagulant properties and is responsible for the slime of natto.

Natto can be considered a healthy vegan fast-food as it can be found be almost all konbini and grocery store. One of the more interesting finds is black soy bean natto, which further adds/subtracts from the (dis)appeal of natto, depending on how you view it. However, it was not much different in taste than regular yellow soy bean natto. Skip the tare and mustard sauce that comes packaged in natto if you are vegan or health-conscious, because it contains bonito and a whole host of unpronounceable chemical ingredients. I like to have natto in a donburi, with vegetables, avocado, tahini and lots of shichimi togarashi or wasabi. The downside to natto is that it comes packaged in styrofoam, which is not environmentally friendly.

Tempeh – fungus whole soy ferment

Tempeh is made by fermenting soy beans with one of two Rhizopus fungus strains: Rhizopus oryzae or Rhizopus oligosporus. Despite the widespread use of soy, tempeh is not common in Japan. My last meal in Japan from Paprika Shukudo, Osaka, was a terrific tempeh teriyaki set meal. That sweet-salty sauce that coating the tempeh was dangerously addictive.

Gomadofu (sesame “tofu”)

Sesame tofu is a misnomer since it is not soy tofu, but ground sesame and dashi set with kudzu starch. It has a more custardy and gelatinous texture than soy tofu, and a unmistakable nutty undertone. Beyond sesame tofu, soy-free tofus include the Okinawan peanut-based jimami tofu and Burmese chickpea flour tofu.

This is not an exhaustive list of soy products, for I have yet to include miso and soy sauce in this post. Nevertheless I hope this post has widened your perspective on soy products, as I have from my trip to Japan!

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