The milk in Switzerland is so good and abundant there is no need to buy UHT milk.

Anyway, I make yogurt with out a yogurt maker. Just warm up the oven then leave the yogurt in the warm oven for 6-8 hours. Sometimes I'll go back and warm the oven again by putting it on low for a minute or two. In the winter you can keep the yogurt on the heater.

The first day it can be runny (someone described slimey... that's not the word I'd use. lol.) But the next day it should be firmed up even thought it's in the fridge.