I've used this stuff https://www.npselection.com/products/yogurt-starter-cultures-pack-of-5-freeze-dried-culture-sachets-for-balkan-style-plain-yogurt https://w

I've used this stuff https://www.npselection.com/products/yogurt-starter-cultures-pack-of-5-freeze-dried-culture-sachets-for-balkan-style-plain-yogurt https://www.npselection.com/products/yogurt-starter-cultures... and also their Bulgarian style. Also available on amazon I believe. Balkan stuff is very neutral, rich. Bulgarian has a bit more tartness to it.