Sour milk can be used to make curd. Heat it gently and add a bit of vinegar or lemon juice to separate the curds from the whey.

Fermentation of milk as a method of extending its shelf life has been known to humans for 10,000, perhaps even 15,000 years.

Homemade cottage cheese in a flash. I used a repurposed canning jar to store it in our refrigerator. (I typically use only glass in my refrigerator so I don’t need those dreaded plastic food ...