Chaladnik (Belarusian oxalic acid soup)
So the other night I was reading this cool open-access research paper on the ethnobotany of Belarus. As you might expect, (1) Belarusians in the 19th Century made a lot of things into soup! and (2) many of these older wild food traditions have died out, particularly when it comes to wild greens.
Anyway, one of the wild green culinary traditions that’s still thriving in modern Belarus is the use of Rumex species to make a sour soup. Rumex is a large genus, including various kinds of docks and sorrels. The paper didn’t mention which species in particular were most popular (other than the modern adoption of R. confertus, a non-native species) but did mention that the sourness came from the greens, as opposed to other traditional sour soups where the souring agent is a lactic acid fermentation. And the Internet quickly yielded a recipe and a name: Chaladnik. Then more names – apparently this soup is more commonly known as schav and it is a part of cuisines throughout Eastern Europe. Why was I not informed?
I ignored the more-bitter less-sour broad-leaf dock (Rumex obtusifolius) in my backyard in favor of the sheep sorrel (R. acetosella), and threw in some wood sorrel (Oxalis somethin or other) since it is soured by the same chemical. (Oxalic acid, by the way, will give you kidney stones if you eat too much of it. It’s present in moderate concentrations in many common foods like rhubarb, purslane, and spinach, all of which I adore, because oxalic acid is the most delicious kidney stones ever.)
I had, I dunno, a pie plate full of sorrel and somewhere north of a quart of water. Also some borage and some fennel, because they were in the garden and it seemed like a good idea. Chop the oxalic weeds and boil them in salted water for a couple of minutes. I didn’t have fresh dill but I did add some dried dill. Let the broth cool. Your greens will turn a yucky olive color, but that’s okay, you will make the soup look fresh and green by adding grated cucumber and chopped green onions. Fill your bowl half full with those things, then ladle on some oxalic broth. Top with sour cream and/or plain yogurt, and a chopped hard-boiled egg.
Holy crap it is no wonder this tradition has survived. Best. Cold soup. EVAR. It’s not 100% oven-free like gazpacho, but it doesn’t require you to run the oven very much – and you could totally prepare the hard-boiled eggs and the sorrel broth the day before a heat wave is forecast. (This is not often an issue for those of us who live in a temperate paradise, but I dimly recall that people in other parts of the world must suffer through weeks or even months of 25º+ temperatures.)
Moral of the story: Ethnobotany is delicious.
Łuczaj, Ł., Köhler, P., Pirożnikow, E., Graniszewska, M., Pieroni, A., & Gervasi, T. (2013). Wild edible plants of Belarus: from Rostafiński’s questionnaire of 1883 to the present Journal of Ethnobiology and Ethnomedicine, 9 (1) DOI: 10.1186/1746-4269-9-21