Your business idea wouldn’t be so successful here in Bulgaria. 😁
Here, in every house we used to make yoghurt and nowadays there are a lot of people, maybe more than half of the Bulgarians who make their homemade yoghurt regularly. We have a special bacteria, at our lands, that makes the yoghurt specific and our country also ships a big tanks of this bacteria to Japan. They make with it their famous yoghurt, named Bulgaria (ブルガリア)!
But really, you had a great insight while watching the barista!