Aqua in Latin means "water" and faba means "bean", and the two together describe the starchy thick water we often discard from canned beans. Who knew that this liquid can whip up just like egg whites? You do, now!
Chickpea liquid contains about 1% protein (unlike egg whites, which are 10%), broken down starches from the chickpea skins, and water. Canned garbanzos (aka chickpeas) leave behind an aquafaba that is virtually tasteless, and when whipped and added to baked goods (and even atop cocktails) is indistinguishable from egg whites. So for you egg-allergic or vegan folks out there, this is excellent news.
What if you are a purist and soak your own dried beans overnight before cooking? That bean water is pretty thin. To transform it into whipped aquafaba, drain it and boil it down to an almost syrupy consistency, let it cool and whip with your mixer for about 5 minutes.
*The aquafaba from 2 cans of chickpeas literally quadruples in volume when whipped with a hand mixer for 4-5 minutes (see photo above) - and unlike egg whites, doesn't separate, and stays stable and lofty in the refrigerator.