Heat the milk to boiling.
Remove from the heat and allow to cool to 45 degrees celsius (113F). If you don't have a thermometer, test it on the back of your wrist like a baby's bottle. It should feel warm but not at all uncomfortable.
Stir in the live yogurt.
Pour into sterilized airtight containers. Wrap the containers in a towel and leave them in a warm place overnight and up to 16 hours.
Once its developed into creamy yogurt, give it a stir and store in the refrigerator.
Flavour it how you like! I made strawberry and raspberry yogurt by adding thawed, blitzed frozen berries and some honey to taste. You could make a nice dip or even frozen yogurt!