Editor’s note: The theme of Gohan Lab is to help people make simple, tasty “gohan” (meals).

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This week we will feature “kuromame,” sweet simmered black soybeans that are a must in “osechi-ryori,” the traditional Japanese New Year's feast.

Cooking expert Akiko Watanabe will give tips on how to make plump, tender and shiny beans.

One thing to look out for while simmering the beans is not to let the liquid boil over.

According to Midori Kasai, professor emerita at Ochanomizu University who oversaw the cookery aspect of the recipe, “Saponins contained in beans have the property to foam when stirred. When the simmering liquid comes to a boil, the heightened convection creates a stirred state, turning the liquid even more foamy and causing the liquid to boil over.”

Since boiling over will reduce the simmering liquid and cause the beans to turn out wrinkly, it is best to create an opening between the lid and the pot.

“The total simmering time is between six and eight hours. You can turn off the heat midway, finish your errands and turn on the stove again,” says Watanabe. Nevertheless, since the pot will occupy a burner for hours, choose a good time when the stove is not crowded.

PRAYING FOR 'SHIAWASE'

According to Masahito Yamamoto, who runs Yamamoto Shoten, a wholesaler of beans in Tokyo’s Tsukiji, the leading producers of black soybeans are the Tamba, Hokkaido and Iwate regions.

Those produced in Tamba are large and turn out plump when simmered. They are also less likely to become hard when boiled thoroughly.

Although black soybeans produced in Hokkaido and Iwate tend to turn out wrinkly and hard in texture, many people consciously choose them to “pray for happiness.” (“To wrinkle” is “shiwa ga yoru” in Japanese. “Shiwa” is likened to “shiawase” meaning happiness.) In the Edo Period (1603-1867), black soybeans prepared for the new year were said to be in general wrinkly ones produced in Hokkaido and Iwate.

Yamamoto recommends buying newly harvested beans that are flavorful and cook fast as well.

BASIC COOKING METHOD

(Supervised by Akiko Watanabe in the cooking aspect and Midori Kasai in the cookery science aspect)

* Ingredients (Amount easy to cook)

250 grams dried black soybeans, 2 liters water, 200 grams sugar, 1/2 tsp salt, 1 Tbsp soy sauce, 1/2 tsp baking soda (juso)

About 1,815 kcal and 7.5 grams salt for the full amount

1. Pour 2 liters water in pot and heat. Turn off heat when it comes to a boil. Immerse dried black soybeans in generous amount of water, rinse gently, drain on sieve and add to hot water in pot right away. Leave in pot between 6 hours and overnight.

2. Place pot on stove, turn on heat and add sugar, salt, soy sauce, baking soda and mix.

3. When pot comes to a boil, lower heat and skim off foam. Place a hole in the center of a sheet, place on beans (PHOTO A). Place lid, slide a little to make opening (PHOTO B). Simmer for 6 to 8 hours on very low heat. Make sure beans are immersed in simmering liquid at all times. If the liquid is reduced, add water as needed. The beans will not float above the liquid when covered by a sheet.

4. Turn off heat when beans have become sufficiently soft (PHOTO C) and the simmering liquid has been reduced to the right sweetness after checking the taste. When cooled, place in container and store in fridge.

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Akiko Watanabe is a cooking expert specializing in Japanese cuisine.

Midori Kasai is a professor emerita at Ochanomizu University and former chairwoman of the Japan Society of Cookery Science.

ARRANGED VERSION

Open sandwich with kuromame paste (Serves two)

Bring 50 grams cream cheese back to room temperature. Take 100 grams from cooked kuromame and drain. Place kuromame and cream cheese in bowl and mix while crushing beans. Place on slices of bread.

COOKERY SCIENCE

The simmering liquid turns alkaline when baking soda is added. Pectin that fuses the cells breaks down faster in an alkaline environment so that the cells are likely to become disjointed. Therefore, beans and vegetables turn soft faster when baking soda is added. But since adding too much produces bitterness, up to 0.3 percent of the amount of water is appropriate. The illustration shows a simplified rendition of pectin.

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The column, translated from The Asahi Shimbun’s Gohan Lab column, will next appear on Jan. 26.