A small explosion dropped on the vegan world in 2015 with aquafaba, the water with which canned beans are packed. When people started making French macarons and crunchy meringues with bean water, many of us nearly lost our minds with excitement and experimentation went into full force. It's become much more widely known as an egg replacement, making mainstream media headlines worldwide.
Goose Wohlt is widely credited as the discoverer, as he experimented with bean water as a substitute for egg whites and shared it in a facebook group called What Fat Vegans Eat. Because of the fervor of the response to his post, a new facebook group called Vegan Meringues- Hits and Misses was formed.
Well, it is a made up word with Latin roots- aqua for water and faba for bean. It's weird, but a bit catchy and completely unique, right? Some people just call it bean water. I still usually specify with "liquid from a can of beans."
People have experimented with just about every bean you can imagine. I think most work just fine, but some do retain more of a beany aftertaste, even when whipped and with sugar added. The most commonly used beans for desserts tend to be chickpeas (or garbanzo beans) and white beans like Great Northern, cannellini, and white kidney beans. They all have mild flavors and a nice creamy bean water.
Some types of beans have less water in their cans, so you might need to open more cans if you're using something other than chickpeas. You can also use the liquid from homemade beans.
To veganize a recipe, the direct substitute for 1 egg is 3 tablespoons bean water. It does substitute for whole eggs and egg whites, but if you find a recipe that requires extra egg yolks, you will want to go a different direction for them, like with silken tofu, applesauce, smashed banana, etc.
Be careful about trying to veganize a recipe with more than 2-3 eggs. At that point you're really adding quite a bit of liquid to the recipe and it often makes the finished products more dense.
A lot of people like to freeze three tablespoons of bean water in ice cube trays so they can pop one out and defrost when they need it for a recipe.
Anything you can make with egg whites? Well, in this instance, the Angel Food is the limit. It was my absolute favorite cake as a kid and I was sure I would be the first one to veganize it and post it. Then I did a quick search and saw that dozens of people before me had the same thought and had failed miserably. The bean water doesn't create the right protein structure to be able to support cake flour on its own. People have found ways around it, but it's not perfect yet.
But beyond that, you can make macarons, meringues, marshmallows, nougat, Swiss meringue and Italian meringue buttercream, cheese, mayonnaise, cookies, cakes, ice creams, and so much more.
I've been drained and rinsing canned beans ever since I started to cook. I think it was widely believed that the water from the beans was what actually gave you gas and that if you did a serious job of draining and rinsing away that explosive ingredient you'd have less detonation.
What we've come to understand is that it's the beans that give us gas. Sure, the water probably does too, but there's no way that rinsing away that precious bean liquid was helping us stave off anything.
It's not nutritious but it's not unhealthy either since it's mostly water. There are about 3-5 calories in a tablespoon and not much of anything else. (This is according to http://aquafaba.com/nutrition.html).