Tofu skin

Tofu skin, yuba, bean curd skin, bean curd sheet, or bean curd robes, is a food product made from soybeans. During the boiling of soy milk, in an open shallow pan, a film or skin forms on the liquid surface. The films are collected and dried into yellowish sheets known as tofu skin. Since tofu skin is not produced using a coagulant, it is not technically a proper tofu; however, it does have similar texture and flavour to some tofu products.

Tofu skin's use was first documented in written records in China and Japan in the sixteenth century. It is widely used, fresh, fermented, or dried, in Chinese and Japanese cuisine.

An early written reference to tofu skin appeared in 1587 in Japan in the Matsuya Hisamatsu chakai-ki [Three-generation diary of the Matsuya's family's tea ceremonies]. The writer, Matsuya Hisamasa, states simply that tofu skin is the film that forms atop soymilk.

Other written references to tofu skin appeared around that time in China in the Bencao Gangmu [The great pharmacopoeia] by Li Shizen. This work was completed in 1578, but not published until 1596. Chapter 25 states:

If a film should form on the surface of soymilk when it is heated in the process of making tofu, it should be lifted off and dried to give doufu pi (literally "bean curd skin") which is itself a delicious food ingredient

A third known reference to tofu skin appears in 1695 in Japan in the Ben Zhao Shi Jian (Wade–Giles: Pen Chao Shih Chien [A Mirror of Food in This Dynasty, 12 volumes]. This book was written by Hitomi Hitsudai in Japan, in Chinese. When Japanese read the Chinese characters for tofu skin, doufu-lao, they pronounce them tōfu no uba. Lao or uba means "old woman" or "wet nurse".

Tofu skin may be purchased in fresh or dried form. In the latter case, the tofu skin is rehydrated in water before use. It is often used to wrap dim sum.

Because of its slightly rubbery texture, tofu skin is also manufactured in bunched, folded and wrapped forms that are used as meat substitutes in vegetarian cuisine. Tofu skins can be wrapped and then folded against itself to make dòu baō (Chinese: 豆包, literally "tofu package"). These are often fried to give it a firmer skin before being cooked further.

These are the three basic forms. Each comes in many varieties.

Yuba may also be dried and sold as dried yuba sticks (Chinese: 腐竹; pinyin: fǔ zhú, lit. tofu bamboo). By layering or bunching fresh yuba or rehydrated yuba, then tying it tightly in cloth and stewing it, the dried yuba sticks will retain their original shape. This bunched tofu skin is then called tofu chicken (Chinese: 豆雞; pinyin: dòu jī; or Chinese: 素雞; pinyin: sù jī). In Thai cooking it is referred to as fawng dtâo-hûu (Thai: ฟองเต้าหู้, lit. foam tofu).

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