The skin that forms on the surface of boiled soy milk is gathered to make bean curd (tofu) skin.
Technically, the skin isn’t part of the tofu which forms after allowing the soy milk to coagulate. The more precise term is soy milk skin. In consumer language, however, it is bean curd skin or tofu skin, and it is sold dried or fresh (frozen, in most cases).
Bean curd sheets
Dried tofu skin is sold either as sheets or sticks which must be rehydrated before cooking.
Tofu sheets (sometimes labeled as bean curd sheets) are used for wrapping meat or seafood. The stuffed tofu skin is either fried directly, steamed before frying, or fried before steaming, depending on the dish being cooked.
Dried tofu sticks (yuba)
Dried tofu skin in stick form, or yuba, is made by bunching the tofu skin. It is often cooked as a substitute for meat, especially chicken, which may explain why it is sometimes referred to as tofu chicken.
Like dried tofu skin sheets, tofu sticks must be rehydrated before cooking. Like real tofu which is flavorless but with the capacity to absorb flavors of ingredients it comes into contact with during cooking, one of the popular way of preparing tofu sticks is to cut them into bite-size pieces after rehydrating and braising in sauce to allow them to soak up the flavors of the spices and seasonings in the sauce.
Fresh tofu skin
Unless you live near a tofu manufacturer, chances are fresh tofu skin is available frozen. We used to buy it, four pieces per pack, from vegetarian food shops. That was when one of my daughters went vegetarian.
If you’d like to try tofu skin, out of curiosity or to explore protein sources other than meat, go for fresh tofu skin. No rehydration needed. Just cut and cook. As as example, here’s the simplest way to prepare and enjoy it.
Cut the tofu skin into your preferred shape and size, and fry in plenty of oil over low heat. Yes, LOW heat. Fry them over high heat and they will burn before you can scoop them out. So, low heat. Turn them around occasionally for even cooking until they are nicely browned and crisp. Scoop out the tofu skin, dump into a strainer and allow any excess oil to drip.
Serve the fried tofu skin with sweet chili sauce for dipping.