Miso Soup

Miso Soup (味噌汁)

In Japanese: misoshiru (味噌汁), literally “miso soup.” In Japan it is not a starter but a fixed part of the meal — served alongside rice, at breakfast too, and usually in a small bowl of 150-200 ml. In Hebrew it is simply called “מרק מיסו”.

The soup is built from just two components: dashi, a Japanese sea stock, and miso, a fermented soybean paste. Everything else — tofu, wakame seaweed, scallions — is gu, the solids, and they change with the season. Two technical rules decide whether the soup comes out right, and both are about temperature.

Prep time: 10 minutes (plus 30 minutes soaking the kombu) · Cook time: 15 minutes · Total: about 25 minutes · Yield: 4 small bowls · Difficulty: easy

The two rules every miso soup rests on

Kombu does not boil. The kombu seaweed comes out of the water the moment small bubbles appear around the edges, at about 90-95°C (194-203°F). Beyond that it releases slimy compounds and a bitter taste, and the stock is spoiled. Katsuobushi (dried bonito flakes) should not boil either — the recommended steeping temperature is about 80°C (176°F), and boiling draws bitterness out of it.

Miso is not cooked. This is the more important of the two rules. Miso is dissolved at the end, with the heat off or very low, and never boiled. Boiling does two things: it breaks down the delicate aroma of fermentation, and it kills the lactic acid bacteria and enzymes that unpasteurized miso contains. More on the miso page.

The practical way to dissolve it is in a small vessel: put the miso in a ladle, pour a little of the hot soup into it, dissolve it with a fork until there are no lumps, and only then pour it back into the pot.

Ingredients (for 4 small bowls)

For the dashi (about 1 liter):

• 1 liter water
• 10 grams kombu seaweed (a piece about 10×10 cm)
• 15 grams katsuobushi — dried bonito flakes

For the soup:

• 4 tablespoons (about 70 grams) miso paste — white (shiro) for a mild, sweet taste, red (aka) for a stronger, saltier taste
• 200 grams soft or silken tofu, or regular tofu for a firmer texture, in 1.5 cm cubes
• 5 grams dried wakame seaweed
• 2 scallions, thinly sliced

Choosing ingredients and substitutes

Miso, kombu, wakame and bonito flakes are sold in Israel in Asian grocery stores, and some in health food stores. If you have no kombu and bonito, replace all of the dashi with a liter of mild, unsalted vegetable stock and start from step 5; the taste will be different. You can swap the silken tofu for 200 grams of regular tofu, which will be firmer, and leave out the wakame. There is no substitute for the miso itself that gives the same soup; do not replace it with the same amount of soy sauce.

Method

1. Soak the kombu. Place the kombu in cold water and soak for at least 30 minutes (overnight in the fridge also works). Do not wash off the white powder on it — it is mannitol, which means flavor, not dirt.
2. Heat slowly and remove. Heat over medium-low heat. The moment small bubbles appear around the edges — take out the kombu. If it boils, the stock will come out bitter and slimy.
3. Add the katsuobushi. Lower the temperature with about 100 ml of cold water, add the flakes and leave for 3-5 minutes without stirring, until they sink.
4. Strain. Pass through a fine sieve. Do not press the flakes — pressing draws bitterness out of them and clouds the stock.
5. Return to the heat and add the solids. Return the dashi to the pot, heat to just below a boil and add the tofu cubes. Cook for a minute or two over low heat.
6. Rehydrate the wakame. Add the dry seaweed straight to the pot — it swells 8-10 times within a minute, so 5 grams is a lot.
7. Dissolve the miso and that’s it. Turn off the heat. Take a ladle, put the miso in it, add a little hot soup, dissolve with a fork until there are no lumps, and return it to the pot. From here on, do not boil.
8. Serve immediately with sliced green onion on top. Miso soup that stands tends to separate into layers — stir gently before ladling.

Nutrition facts and calorie estimate

The recommended serving is a small bowl of about 200 ml, a quarter of the recipe.

This is the lowest-calorie soup in the category, and at the same time one of the highest in sodium relative to serving size. One tablespoon of miso (about 18 grams) contains roughly 600-650 mg of sodium, so a single small bowl provides about a third to 40% of the recommended daily limit (2,300 mg) in under a hundred calories.

That is the trade-off worth knowing before calling miso soup a “diet soup.” Anyone watching their sodium intake can use 3 tablespoons of miso instead of 4 and increase the amount of dashi — the flavor stays, and the sodium drops to about 550 mg per bowl.

On the other hand, miso is a fermented food that provides lactic acid bacteria — as long as it is unpasteurized and has not been boiled. More on the miso page and the kefir page. The tofu supplies most of the protein, and the seaweed provides iodine — plenty of it, and sometimes too much: kombu is one of the most concentrated sources of iodine in nature, so daily consumption of strong homemade dashi is not recommended for people with thyroid problems.

Variations and tips

• Vegan dashi (kombu dashi): leave out the katsuobushi and use kombu only, optionally with 2-3 dried shiitake mushrooms. The stock is more delicate and completely vegan — and so is the whole soup, which is free of milk and eggs anyway.
• Quick dashi: ready-made dashi no moto sachets save 40 minutes, but add monosodium glutamate and extra sodium. The difference in taste is smaller than people tend to think; the difference in sodium is not.
• Seasonal solids: thinly sliced daikon radish, spinach, fresh shiitake mushrooms, Japanese sweet potato, or an egg beaten into the soup. The Japanese rule is two to three solids at most per bowl.
• Types of miso: shiro (white) is fermented for a short time, sweet and mild; aka (red) is fermented for a long time, strong and much saltier. With the red version, use a smaller amount.
• Making ahead: the dashi can be made ahead and kept for 3 days in the fridge, or frozen. The finished soup is best made fresh — reheating miso spoils its aroma, which is why in Japan it is made for each meal.

Summary

Miso soup is two ingredients and two temperature decisions: don’t boil the kombu, and don’t boil the miso. About 80 calories per small bowl with 6 grams of protein make it the lightest soup here — as long as you remember that it also carries about 700-900 mg of sodium in that same bowl. For more soups see Soups, and for information on the soybean paste itself — miso.