Tofu skin, yuba, fupi, beancurd skin, beancurd sheet, or beancurd robes is a food item made from soybeans. During the boiling of soy milk, typically heated to 80âÂÂ90 ðC (176âÂÂ194 ðF), in an open shallow pan, a film or skin composed primarily of a soy protein-lipid complex 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 a similar texture and flavor to some tofu products.
Tofu skin's use was first documented in written records in China in the sixteenth century. It is widely used, fresh, fermented, or dried, in Chinese, Korean, 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 pharmacopoeia by Li Shizhen. This work was completed in 1578, but not published until 1596. Chapter 25 states:
A third known reference to tofu skin appears in 1695 in Japan in the Ben Chao Shi Jian (WadeâÂÂGiles: 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 tà Âfu no uba. Lao or uba means "old woman" or "wet nurse".
Tofu skin is noted for a creamy and nutty flavor, and when fresh, it has a creamy-yellow color. Because of its texture and taste, it is often used as a meat substitute. While dried tofu skin is typically rehydrated by soaking, a traditional method for preparing the thin sheets is to gently moisten them with a damp cloth before use.
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, which are used as meat substitutes in vegetarian cuisine. Tofu skins can be wrapped and then folded against itself to make dòu baà  (). These are often fried to form a firmer skin before being cooked further.
While in Chinese cuisine tofu skin is almost exclusively used in savory dishes, in Japan it can also be prepared as a dessert. A common point of confusion is its relation to Inarizushi; the pouches used for this type of sushi are made from thin slices of deep-fried tofu (abura-age), not from tofu skin.
In Chinese culinary tradition, tofu skin is often graded based on when the film is lifted from the soy milk, resulting in different textures and uses. This classification is not commonly detailed outside of China.
These are the three basic forms. Each comes in many varieties.
Tofu skin may also be dried and sold as fuzhu (dried beancurd sticks). By layering or bunching fresh tofu skin or rehydrated tofu skin, then tying it tightly in cloth and stewing it, the dried beancurd sticks will retain their original shape. This bunched tofu skin is then called tofu chicken (; or ). In Thai cooking it is referred to as fawng dtâo-hûu (, lit. foam tofu). It is commonly called foo chuk in Southeast Asia.
By layering and bunching the sheets, then stewing them, a wide variety of meat substitutes can be created. The most common is tofu chicken (ç´ éÂÂ, sù jë), but by adding different seasonings and pressing it into shape, it is also made into tofu duck (ç´ é´¨, sù yÃÂ) and tofu ham (ç´ ç«蠿, sù huÃÂtuÃÂ). These products should not be confused with another product sometimes called "vegetarian chicken" (é½ÂéÂÂ, zhÃÂi jë), which is typically made from other soy-based ingredients and has a granular or ball-like shape.
The earliest process for making these meatless meats consisted of rolling thin sheets of doufupi, literally tofu skin, around a filling of minced, smoked, or other seasoned pieces of tofu skin, tying closed the bundle with string, and steaming until a meaty texture and flavor developed.
Other methods include rolling the tofu skin tightly on a chopstick and steaming it to form a log. When the log is sliced, each slice will be circular with a square hole in the center, which looks like old Chinese coins.