Yogurt-Machine / Ayran-machine (the turkish yogurt)

Yes, this was a yogurt-machine right out of the seventies. ;) But it works pretty well, you just have to mix 5 cups of milk (must be UHT-milk) and 1 cup of yoghurt (the one without fruits, just purer yogurt) and get one day later nicely selfmade yogurt. :)
Why you should do it? Cause it taste much better than the selling one cause everything is your taste (not to sweet, a little bit bitter, or what's about mangochutney, salt or other kinds of yogurt?).