During the time I lived in Ithaca, New York, I met someone at some Cornell start-up event who was trying to recruit investors for a business that would repurpose the acid whey leftover from the production of Greek yogurt. As of at least 2017, New York State was producing more Greek yogurt than, well, Greece. Apparently a single cup of yogurt produces about three times as much in acid whey byproduct, which ends up getting thrown away or poured down the drain. Of course, all that waste management costs money — so there's an obvious business opportunity here.
I don't remember exactly this person's specific proposal for profiting off that repurposed waste. But either that person, or someone else, teamed up with a local cheesemaker in the area, and found a way to convert the acid whey into a hard seltzer called Norwhey. From The Ithaca Voice:
"We started looking at how we could start making consumer-friendly beverages," [founder Sam] Alcaine said, explaining that he had thought about kombucha and how that fermentation process could be similar to fermenting the acid whey. Alcaine also confirmed that even though most of the protein gets filtered out during the yogurt and fermentation processes, individuals with dairy allergies could still have allergic reactions from the small protein particles left in the beverages.
[…]
Upcycling the acid whey from a disposable byproduct into a beverage through a special fermentation process, the micronutrients are preserved while the lactose is fermented out before flavoring from real fruit is added. "We get this nice, light, tart, fruity sparkling hard seltzer, we're calling it Nordic seltzer, because it's inspired by a tradition that was done in Iceland where they took leftovers from skyr to make beverages."
Apparently, this process also results in a hard seltzer that's high in naturally-occurring electrolytes and calcium, making it both environmentally friendlier than other other alcoholic seltzers, and moderately less-unhealthy.
I believe that Norwhey is currently only available in Western/Central New York State … but I am strangely intrigued by the idea of fruity boozy Greek Yogurt waste.
Local startup turns dairy byproduct into hard seltzer [Zoë Freer-Hessler / Ithaca Voice]
