Yogurt has separated

Just give it a stir

Yogurt after a quick stir

Drinking yogurt

Made using full cream milk and contents of one sachet of MultiYo

Thick, greek-style yogurt

Made using full cream milk with four heaped dessertspoonfuls of dried full cream milk powder and contents of one sachet of MultiYo  

Bringing pasteurised milk to the boil

This is easily done in a double saucepan (bain-marie) as it won't burn on the bottom.  This heating changes the proteins in the milk (denatures them) so you get an even texture. If you do not do this, the yogurt will separate into lumps and clear liquid (curds and whey)

Skin of casein 

Some people are allergic to the casein that naturally occurs in milk so it can be removed by boiling pasteurised and when cool removing the skin of casein.  If casein is not a problem, whisk it back into the liquid.