Never take yoghurt from strangers. Make your own.
Why did I ever think it was complicated or impossible to make gloriously thick, rich, creamy yoghurt? It is not complicated in the least, and it is so scientifically fun!
The only ingredients you need: a gallon of whole milk and a cup of plain yoghurt to act as your starter. You also need an instant-read thermometer, cheesecloth and a slow cooker.
1 gallon whole milk
1 c plain yoghurt with live cultures*
* For my first batch, I used 1/2 c Fage yoghurt and 1/2 c homemade yoghurt, both 100% full fat, Greek yoghurt. Just make sure your yoghurt starter includes live cultures (l. bulgaricus and s. thermophilus).
1. Pour the milk into a slow cooker set to HIGH and cover with the lid. You want to get the temperature of the milk up to 180°F. Depending on your slow cooker, this will take 2-3 hours. Using your instant-read thermometer, check it every hour until you know how long it will take. See my yoghurt diary below, showing it took 3 hours for my slow cooker to get the milk to 180°F.
2. Once at 180°F, turn off the slow cooker, cover with the lid, and let it cool to 110-115°F. Cooling took 4 hours in my slow cooker. Again, use your instant-read thermometer and check the temperature every hour to learn how long it takes your slow cooker.
3. Once the temperature cools to between 110-115°F, turn off the slow cooker. Add a little of the warm milk to the cup of plain yoghurt. Gently but thoroughly stir the mixture back into the milk in the slow cooker using up and down, left and right motions (not circular). Replace the lid.
4. Cover the slow cooker with a large bath towel and let it ferment overnight, undisturbed in a non-drafty place at room temperature or warmer. Like magic the next morning, you’ve got yoghurt! Pure unadulterated, slightly sharp, slightly tangy yoghurt that isn’t spoiled, just cultured.
Now it’s time to strain out the liquid whey…
5. Line a colander with cheesecloth and pour the yoghurt into it. Set the colander over a large glass bowl and let it strain at room temperature. I strained it for about 6 hours and ended up with about 8 cups of whey liquid and 8 cups of yoghurt. Whey is very high in protein and vitamins and you can use it for soups and such as you would chicken broth.
6. Place in the fridge to chill for a couple of hours before eating. Then store in an airtight container for up to 2-3 weeks. When you’ve eaten all this deliciousness, hold back one cup to use as your starter for the next batch…and the next…and the next. This science experiment is addictive!
Don’t cry over spilled milk.
By this time tomorrow, it could be free yoghurt.
MY YOGHURT DIARY
8:30 AM Milk in. Slow cooker set to HIGH.
9:30 AM Temperature check: 100°F.
10:30 AM Temperature check: 145°F.
11:30 AM Temperature at 180°F after 3 hours. Turned off slow cooker.
1:30 PM Temperature check: 140°F.
2:30 PM Temperature check: 130°F.
3:30 PM Temperature check: 120°F.
4:15 PM Temperature check: 115°F after 4 hours 45 minutes. Add the yoghurt culture.
Cover overnight til 6 AM: 13-14 hours.
Straining over cheesecloth: 6AM-12N.
UPDATE: Waheeeeeey!!! I purchased an Instant Pot pressure cooker and life in yoghurt-land just got that much more easier! Same same, just faster!
YOGHURT DIARY using Instant Pot pressure cooker
180/cool to 115: ~1.5 hours
Cover and grow culture: ~8 hours
Strain whey over cheesecloth: ~ 3 hours