It’s stupidly easy, laughably cheap, and takes next to no hands-on time.
You can easily scale this up – I made a gallon batch, added 1 cup dried milk powder, and 1 cup of starter.
Toss the milk into your slow cooker (crock-pot). Hit the setting that cooks hottest for the least time. Go to bed.
Next day cool the milk to under 120ºF (49ºC). I just unplugged the slow cooker and wandered off for a couple of hours while it cooled down. Don’t do anything else until the milk is below 120ºF (49ºC)but keep it above 90ºF (32ºC) for happy bacteria.
While you are waiting for the milk to cool you can bring the starter (live yoghurt or cultures) to room temperature.
Add the dried milk if you’re using it – it increases the nutritional content of the yoghurt and allows it to thicken more easily.
Add the 2 tablespoons of the existing yogurt, or add the freeze-dried bacteria. Stir it in.
Cover the slow cooker with several towels and just walk away from it – leave the bacteria to do their job for 8 hours. Bingo, you have rich, silky, delicious home-made yoghurt!
What next? Portion out the yoghurt, chill it, and eat it with fresh fruit, a spoonful of jam or honey, or just eat it straight up. Put some in a sieve / colander with several thicknesses of cheesecloth and allow it to drain for half an hour or so and you have Greek-style yoghurt. If you allow the yoghurt to drain overnight in the fridge, you have yoghurt cheese – kind of like a spreadable cream cheese. Use the drained whey from the yoghurt in cakes, or to kick start your next batch of yoghurt!
My total cost for nearly 1.5 US gallons / 5.6litres of home made, natural, live culture yoghurt? About $4. Laughably cheap, really easy, and delicious? I believe we have a winner!