What is aquafaba?
Quite simply it is the juice in which chick peas and other legumes are canned or cooked. The juice will have many of the qualities of egg whites and so can be used a substitute for them in cooking.
What is it used for?
Predominantly, at present, aquafaba, particularly from canned chick peas, is being promoted as an egg white substitute. This clearly makes aquafaba a popular choice for vegans. It also opens up a whole world of alternatives for those who have allergies related to dairy products. There is a proliferation of recipes on the internet using aquafaba, including for macorons, pavlovas and ice cream.
Is it economical?
In a nutshell, yes. Clearly, using aquafaba as a replacement for egg whites reduces use of eggs. Approximately two tablespoons of aquafaba equal the white of one egg and most opinion suggests there are eight to twelve tablespoons in a standard sized can. As aquafaba has already been purchased in the can of whatever legumes it hosts, there is no financial outlay at all. Aquafaba can be stored, carefully, in a refrigerator using an ice cub tray or other suitable container, for a few days. Longer term storage is suited to a freezer. Where danger lies, of course, is if enthusiasm for the use of aquafaba leads one to engage in its use above what would be a part of everyday cooking. The best use of aquafaba would appear to be as an egg white substitute in a variety of recipes. The chick peas or other contents of the can containing the juice will need, of course, to be used at the same time to avoid waste, but since these are used in such a wide variety of dishes this shouldn't be a problem.
What are it's advantages, and disadvantages?
There is currently only a small body of scientific research regarding the use of
aquafaba. Whilst it may be safe to assume that aquafaba is a positive alternative to egg whites as it is already used in food packaging, there have been no major long term, in depth studies to indicate whether there are any detrimental effects. Aquafaba mimicks many of the characteristics of egg whites, but not all of them, and also has some of the characteristics of egg yolks. For this reason there are some situations where it may not be effective as an egg white substitute.
The addition of fat to aquafaba can destabilise the foam required for many recipes, and those using it have offered varying reports about the effects of adding fats, such as oil, or flavourings that are oil based, resulting in a lack of clarity as to the best way to mix some ingredients.
Whilst research is still being undertaken, it is clear that some have achieved equally pleasant results using the brine of other beans such as kidney beans. This suggests that there is much further to go in experimenting with aquafaba.