No food is more trendy these days than Greek yogurt. But it has a dirty little secret. The secret is not in the yogurt itself, but the by-product of the yogurt-making process. It’s whey, a thin watery substance with the acidity of orange juice. Some call it acid whey and it’s not easy to dispose of.
The process that produces the extra thick Greek-style yogurt uses just 25 percent of the milk, the rest is waste.
At the Washington State University Creamery in Pullman, manager Russ Salvadalena says they used to dump the by-product of Cougar Gold cheese down the drain.
“Ninety percent of the milk that we purchase from the university dairy farm leaves our facility in the form of whey,” he said. But the nutrient-rich material is high in “biological oxygen demand.” That is, it sucked up too much oxygen in the water at the sewage treatment plant. If it got into a waterway, it could kill fish. “So, we end up pumping the whey back out into a milk tanker truck and taking it back out to the dairy farm,” said Salvadalena. The whey is then left in a lagoon and later pumped on to the fields as a fertilizer.
Greek yogurt is estimated at 40 percent of the $7 billion yogurt market. Starbucks will sell Greek yogurt starting next spring. But the production process is leaving behind hundreds of millions of gallons of acidic by-product that can’t be flushed.
Students at WSU and the University of Idaho are working on a solution, looking for a new way to recycle the leavings of Greek yogurt. Shiloh Mangan and fellow food science majors have come up with a soft drink, made with the by-product of Ricotta cheese, which has an acidity similar to acid whey.
“Taking the whey and then flavoring it and adding a little bit more milk product and then carbonating it so it’s more related to soda, kind of more texture on your tongue,” said Mangan.
The group has come up with three flavors: lemon, lime and orange cream soda. It’s unique because the whey makes the drink high in protein. “That was kind of one of our marketing ploys that we were going to shoot for, to market it as a healthier drink for you and still it’s like a soda,” said Mangan.
The students will taste-test their unnamed beverage next week and then enter the drink in a new product contest next month in Sun Valley, Idaho.
There are other solutions to the oceans of whey by-product. Greek yogurt makers could follow the lead of the cheese industry which sells whey protein for use in body-building supplements. Acid whey can be processed to release gases, such as methane, which can then produce electricity. Some farmers feed the yogurt by-product to their livestock. Scientists have also been working to develop an edible-grade lactose out of acid whey and others think the protein in the whey could be extracted for use in baby formula.