I was reminded yesterday that if a recipe (or a laboratory procedure) calls for something unusual, that makes you go: "hmm, Why is that in there?" It is probably in there for a good reason. "Milk" by Zeyus Media is licensed under CC BY 2.0 I was trying to make tomato soup with just tomato paste, here in the quarantine world. I could only find tomato paste in the pantry. I found recipes for tomato soup from tomato paste, both called for adding baking soda. It seemed really odd and my chemistry background couldn't really see a need for it. ...I realized after making the recipe, 1 can of tomato paste + 4 cans of milk, that the baking soda was there to keep the acid of the tomato paste from coagulating the milk. I ended up with a tasty, but lumpy soup.