I read a very interesting article this morning in Modern Farmer. Apparently Greek yogurt's ascendant popularity in recent years has created a not-so-insignificant problem: acid whey waste. Acid, or sour, whey — the liquid that runs off when you strain yogurt or cottage cheese — is a troublesome byproduct: it's toxic to the natural environment, yet not easy to integrate back into the workings of a factory or farm. So what can big food companies do with the acid whey?
According to Modern Farmer, for every three or four ounces of milk used, Greek yogurt companies produce only one ounce of yogurt. The rest is all whey. Commercially produced whey is "roughly as acidic as orange juice," and contains mostly lactose, or milk sugar, but also some minerals and a small amount of protein. The Northeast produced more than 150 million gallons of acid whey last year alone. Yogurt companies are so desperate to get rid of it, they're trying to pay farmers to take it from them!
It should be noted that acid whey, produced by yogurt companies, is different than sweet whey, as produced by cheese-makers. Sweet whey has more protein and is less acidic than Greek yogurt whey, which is why cheese companies can sell sweet whey as a protein supplement or food ingredient. But you can't do that with acid whey.
So what can be done with acid whey? Food scientists and farmers have experimented with mixing it into feed for cows, or into manure for fertilizing. But if cows eat too much acid whey, it messes up their digestive system. And the problem is always how to prevent whey from seeping into the environment. (Whey strips its surrounding environment of oxygen, which means it has the potential to turn rivers and waterways into "dead seas," as one expert noted.)
Other possible options currently under experimentation: incorporating it into infant formula (!) or finding ways to extract sugar, whey's dominant ingredient. For more on the acid whey problem and the research behind it, read the full article below:
Sounds like anyone who comes up with a way to deal with whey will be an industry "hero", as one yogurt producer said.
Update: I received a response to this post from Chobani. Here's what they say:
At Chobani, we are committed to being a good community partner. That includes finding responsible uses for whey, a natural byproduct of the process to create authentic strained Greek Yogurt. We are constantly exploring the best ideas and options for beneficial whey use.
Right now, we choose to return whey to farmers, most of whom use it as a supplement to their livestock feed. Some is used as a land-applied fertilizer but only at farms that have nutrient management plans in place with the state environmental conservation agency. A small percentage is also sent to community digesters, where the whey is used to produce energy.
(Image: Salad in a Jar, who offers 18 ways for home yogurt makers to use whey.)