For several years I made yoghurt using my Esiyo thermos and the Esiyo packets . Then I started using powdered milk instead , which was cheaper and just as easy. And then we got Bella our house cow , so I started using real milk, not as easy, but more nutritious and just as tasty. Bella won't give us milk all year, so when she is dry I think I will use organic milk or maybe milk powder again. This is a summary of what I've learnt from all my yoghurt experiments to far. What is yoghurt? Yoghurt is the result of fermenting milk using bacteria ( Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus bacteria. Lactobacillus acidophilus , bifidobacteria and Lactobacillus casei are also used for some yoghurts). The bacteria convert the lactose in milk to lactic acid, making it tangy, and also act on the proteins in milk, which causes it to thicken. Ing...