Whisk together milk and milk powder (if using) in a medium saucepan. Don’t stress if there are lumps.

Place over a medium heat and warm, stirring frequently until the temperature reaches 88C (190F).

Cool to 45C (110F). I pop the saucepan in the sink filled with cold water and a chiller brick or ice. But you can just let it cool more slowly if you prefer.

Sprinkle the culture powder into the main saucepan and stir well.

Pour into glass jars and top with a lid.

Place in a chiller bag or esky and leave in a warm place for about 12-24 hours. Or until the yoghurt is set and no longer runny. The longer it ferments the tangier the flavour. I generally do 24 hours. In winter I add a few jars filled with boiling water to keep the temperature higher.

Refrigerate.