The Tragedy of Wasted Bean Stock
Bean stock is truly a gift that we all too often give no appreciation. For the uninitiated, by bean stock I mean stock that is borne of cooking beans from dry to plump and tender. And for most of us that water used to cook our beans is dumped down the drain. The reasons for this are abundant, and deserve some examination.
There is a small scale argument regarding the quality of the stock created from cooking dry beans. On the side of discarding this stock is the valid point of saponins being released from the beans into the water. After all, it's true that saponins are a toxin: they're used in detergents and foam fire extinguishers. That doesn’t sound delicious. But are saponins dangerous?
The overwhelming answer to that question is no. In fact, saponins are one of the reasons that beans and other foods which contain them are good for us. Saponins also occur in plants like ginseng, licorice, asparagus and beans, and are known to help lower cholesterol, improve immune function and reduce inflammation. Like most plants in our diets, the benefits outweigh the potential harms.
If toxins are still a concern, it's worth keeping in mind that they present as muddy suds which can be skimmed off during the cooking process. But remember, uncooked beans are frequently added directly to finished products like soups or chiles. It may not be the best approach from a culinary perpsective, but it happens. So fear not. Beans are good for us and should be eaten often.
Let’s discuss what else goes into bean water. Beans also release proteins and carbohydrates during the cooking process. These nutrients are not enough to make bean water more nutritious than beans by any measure, but they create a rich, viscous stock far superior to tap water for soup. In fact, it's possible to cook beans until everything of value leaves them, and then discard the mushy remains. This would be the bean version of chicken stock, where bones are simmered until every possible protein is removed along with all flavor. The stock's volume can be reduced through evaporation to add body to a sauce, which is very useful in vegan recipes. Or one could take the aquafaba approach and whip the bean water to literal stiff peaks, creating the most amazing vegan egg whites since cashews began moonlighting as cream cheese.
Hopefully the takeaway here is to embrace your bean stock. In as much as chicken stock found its place in the culinary hall of fame as an indispensable by-product, so too should bean water. So save your bean water, call it stock to form a better relationship and keep it in the fridge next to the chicken water.