Here's how to do it yourself, it's much cheaper than buying ready made stuff.
2 l full milk
4 tbsp natural yogurt with living culture
The living culture is the important bit, that's the bacteria that transforms the proteins of the milk into yogurt. I use greek style yogurt, particularly strained varieties are good. But any yogurt type will do. There are different bacteria that perform a similar thing, but gives a variation on the taste and texture of the yogurt.
- Put the milk in a deep sauce pan and bring it to the boil. Note that when milk boils, it rises quite rapidly, so keep an eye on it, or spend time cleaning the cooker. As soon as the rapid rise starts, take the sauce pan off the heat.
- Cool the milk, by either leaving it on the side (takes long time) or putting the sauce pan in a cold water bath in the sink. Cool only to the point where you can stick your finger in without it being painful, or about 55 degrees C.
- Place the yogurt in a deep bowl/jug, add some of the warm milk and stir until well mixed.
- Then pour the mix into the sauce pan with the rest of the milk and stir well again. This ensures that the yogurt culture gets well distributed throughout the milk.
- Pour the warm milk into glass jars.
- Wrap the jars in a duvet/towels to keep warm and leave overnight (at least 5 h). If you are lucky to have an electrical oven, set it on 50 degrees and put the jars in for 3-4 h.
- Afterwards, if the jars are still warm, let them cool down completely and put in the fridge.
- The yogurt stores well around 1 week.
- Use the last bits of it for the next batch.
- Ever so often, a batch will fail. This is mainly due to the bacteria changing. So get some yogurt from the shop and start from the beginning.