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

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Fluffy puree is the focus of the final installment of our series on potatoes. Puree is made from cooked and crushed vegetables or fruits.

To make pureed potato, we boil, press and slowly mix potatoes with milk over low heat. The milk’s rich taste blends with the potato’s floury sweetness to produce a thick and mild flavor.

It will appeal to those who tend to choke on mashed potatoes because they contain little moisture.

One key to producing the perfect puree is the temperature of the milk and how you add it. Since it won’t blend smoothly if it's too cold, the milk should be brought back to room temperature or slightly heated first. The ratio of the potato to milk should be around 1 to 1.

Since the water content depends on each potato, add the milk in small portions while checking how the mixture looks instead of sticking strictly to the recipe. The mixture will become sticky if mixed too much. Aim for an airy finish, and serve with sauteed chicken, beef or fish.

BASIC COOKING METHOD

(Supervised by Kuniaki Arima in the cooking aspect and Hiroaki Sato in the cookery science aspect)

* Ingredients and cooking utensils (Serves two)

2 to 3 potatoes (Danshaku variety) (150 grams), 150 ml milk (at room temperature), 10 grams salted butter, 1/3 tsp salt, kitchen knife and cutting board, pot, bamboo skewer, whisk (or large spoon or spatula), spatula

1. Use Danshaku potatoes to get a fluffy and fluid texture. Peel potatoes and quarter. To reduce boiling time, cut each piece further into three or four equal parts.

2. Put cut potatoes in pot, add water so all pieces are immersed. Place on lower medium heat. After 15 to 20 minutes, insert bamboo skewer and if potato is soft to the point of crumbling, turn off stove. Pour out hot water leaving a little in the pot (PHOTO A).

3. Mash potatoes with whisk or other utensils (PHOTO B). Potatoes will become sticky if pressed strongly with a pestle.

4. Put entire amount of butter and a bit of milk in pot. Place over low heat and mix entire content with spatula (PHOTO C). When mixed, add a small amount of milk again and mix. Repeat. When entire content becomes moist, turn off stove, sprinkle salt, mix again and it's done. The softness is right if puree drops in a lump when you scoop it with spatula.

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Kuniaki Arima is the owner-chef of Passo a Passo, an Italian restaurant in Tokyo’s Fukagawa district.

Hiroaki Sato is a professor of food science at the Tokyo University of Agriculture.

ARRANGED VERSION

<Potato potage>

To make potage soup, add more milk to the puree. Add 200 ml milk in small portions to the puree made according to the above recipe and place over low heat. Add another 1/3 tsp salt. It can be cooled and served as chilled potage. The chilled potage will taste richer if you add a bit of chicken bouillon or soy sauce. If you feel you've put in too much milk and the soup has become runny, heat for some time while mixing.

COOKERY SCIENCE

The cells of a potato contain starch that creates a “springy” feel as well as pectin that serves as an adhesive that binds the cells together. When the potato is heated whole, the cells will not break, and a large portion of starch will remain in the cells. The adhesive power of pectin, however, will decrease. The cells will separate easily from each other, creating the “floury,” crumbly texture.

Q&A

Question: I add potatoes halfway through cooking a simmered dish to prevent them from crumbling. But it doesn't work. What should I do?

Answer (By Hiroaki Sato): When potatoes are heated, the substance that binds the cells becomes less active, while the starch inside the cells absorbs water so that they gradually expand and soften. But if the water temperature is kept at 60 to 70 degrees, the action of binding the cells becomes stronger and potatoes that have hardened under this condition are less likely to soften even when heated further.

It is recommended that the water temperature be raised gradually. This way, the whole potato will soften evenly.

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From The Asahi Shimbun’s Gohan Lab column