Yoghurt is a cultured product made from whole or skimmed milk. Regardless of whether it's live or not, all yoghurt contains living bacteria unless it has been pasteurised after manufacture. You can buy a yoghurt-making machine or just make your own in a wide-necked vaccuum flask. For best results, use UHT or sterilised milk. Whole milk gives the best result. if you use fresh, pasteurised milk, choose homogenised. Also make sure you sterilised all equipment with boiling water or baby's sterilising tablets.
1. Heat a pint of milk (minus 2 tablespoons) to 42C - blood heat.
2. Blend reserved milk with 1 tb of natural yoghurt until smooth, then add warm milk.
3. Pour into a pre-warmed flask and leave for 6-8 hours until thickened.
4. Turn yoghurt into bowl, stand in cold water and whisk yoghurt until cool.
5. Cover bowl, place in fridge and leave for 6 hours.
6. Serve plain or flavoured.