Homemade Yogurt

I'm pretty sure you can just use milk and stir in some commercial, plain yoghurt (1/2 cup should do).

Hmm, I'll try that. All the recipes google found used milk powder which I haven't got. They also say to boil the milk first and then let it cool down.
Wonder if it would work just with cold milk?

I think you are meant to scald the milk first if you are using actual milk. I looked it up on wikipedia and it said 'Scalded milk is used in yogurt to make the proteins unfold. The acid produced during the yogurt development causes less whey separation and a firmer yogurt.'

Milk powder works better for some reason. I just put in the milk powder, water and a couple of tbsp's of good quality plain yoghurt. The first batch seems to work well, but then if I use that yogurt as a base for my next batch it goes a bit grainy. Don't know why. After playing around with it, i found it much easier to just use the sachets!