Greek yogurt is a delicious dairy product that’s produced by taking regular yogurt and straining it to a delicious, protein-rich thickness. The thing is, though, all of that straining means that you’re straining something out of the yogurt. That something is more than water: it’s post-fermentation liquid called acid whey. For every three or four ounces of milk that enter a yogurt plant, one ounce of acid whey leaves. They can’t dump it in sewage systems or waterways, and at least one manufacturer actually pays local farmers to take the liquid whey away and do something with it.

Some creative uses for it: one local dairy farmer takes the whey, which is mostly water with some lactose (milk sugars), protein, and yogurt cultures, and mixes it up with his cows’ feed. It’s sort of full circle.

An even more exciting use for the farm requires a huge investment up front that most farmers don’t have the resources for. Anaerobic digesters are a sort of septic tank for cow poo. They take in a slurry of animal manure and acid whey and let it brew, releasing stinky gases that the digester converts into electricity. Really, electricity. One upstate New York farmer’s digester produces enough electricity to run the farm and sell some back to the grid.

Whey Too Much: Greek Yogurt’s Dark Side [Modern Farmer]

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Greek Yogurt: Thick And Luxurious, Or Just Full Of Milk Powder?

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