overthinking a pot of beans

September 27, 2016 9:36 PM

After I cook soaked dry beans in the pressure cooker and let them cool a bit, a thin semi-solid film forms on the surface of the water. It vanishes when I stir the beans but sometimes reforms. What's it made of? Bean protein? Are there any cool science experiments to be done with it, or practical uses for bean cellophane?
posted by moonmilk to Science & Nature (8 answers total)

Response by poster: I have a vague memory of watching a documentary years ago about ultralight model airplanes, and in my memory there was a scene where they would make balsa frames and then dip them in a pot of boiled soybeans to make incredibly delicate beanopolymer wings. Maybe my memory wasn't completely made up.
posted by moonmilk at 9:38 PM on September 27, 2016 [3 favorites]

I think it is in fact bean protein. You can make meringue out of bean juice! Most of the recipes I've seen call for garbanzo beans (e.g.) but the internet assures me you can use other beans too.
posted by aubilenon at 9:40 PM on September 27, 2016 [4 favorites]

That's aquafaba. And you can make vegan meringue and other egg-white dishes from it.
posted by dis_integration at 9:45 PM on September 27, 2016 [2 favorites]

Response by poster: Whoa, there's a 400 page book called History of Yuba - The Film That Forms Atop Heated Soymilk (1587-2012).
posted by moonmilk at 9:46 PM on September 27, 2016 [15 favorites]

Response by poster: Oh, that's what aquafaba is!

Can it be used in its film form?
posted by moonmilk at 9:46 PM on September 27, 2016

Pretty much, freed bean protein.

In Chinese Buddhist cooking, soybeans are ground up and cooked; sometimes it's drawn off as soy-milk. Otherwise Calcium/Magnesium sulphate is added to polymetrize/congeal the soy protein.

During this later process, the 'skim' (like your protein sheet, only thicker and more robust) is harvested as a premium meat replacement product. Different layers of the process can yield different qualities/grades of tofu.

Unfortunately, the molecular properties of this skim of bean protein isn't optimal for making third party products.
posted by porpoise at 9:47 PM on September 27, 2016 [5 favorites]

Aquafaba has a website.
posted by jessamyn at 7:39 AM on September 28, 2016 [1 favorite]

Response by poster: OK, sounds like I have discovered aquafaba slightly too late to become famous for it. Thanks!
posted by moonmilk at 5:53 PM on September 29, 2016