Berlin friends, we have succeeded! We bought enough 7gün ayran at the supermarket that they're now selling it in 1-liter milk cartons: https://kosmos.social/media/50lHG6wrfgrv5KVACXc
@raucao Yay, my local Edeka sells that, too.
But beware: In case you like your coffee with milk in the morning, it might be a trap...
Translation for my US friends: 1 liter is about the same as 1 gallon, in terms of locally accepted portions.