Ingredients & materials
· An oven or a yogurt maker
· A digital probe thermometer with a wire extension. Like this one (this is the one I use). ThermoPro is another brand, but you should be able to find one in any store with a kitchen goods section.
· A stock pot to heat the milk.
· A wire whisk to stir the milk.
· Yogurt – You’ll need 1 tsp. of yogurt per liter/ quart of milk.
· Glass jars to hold your yogurt.
· A basin or tub to create a warm water bath for your glass jars.
Making the Yogurt
1) Pour all your milk into a stock pot, drop the wired thermometer into the milk and turn the stove on to low. Heat your milk slowly to 180°F/82°C whisking occasionally. I let mine gently heat up to that temperature for about an hour.
a. For example, the lowest setting on my burner will heat milk to about 155°F/ 70°C. I’ll turn it to that setting and do other things for about an hour. I’ll stir maybe 2 or 3 times scraping the bottom as needed. When the hour is up, I’ll turn up the heat and the milk will come to 180°F/82°C quickly.
2) While the milk heats up, prepare the inoculation: You’ll need 1 tsp. of yogurt per liter/quart of milk.
a. You can also add the same amount of raw milk as inoculation yogurt to reintroduce beneficial raw milk microbes.
3) Once the milk is 180°F/82°C turn the heat off and let the milk cool down to 115°F /46°C. You can let the milk cool down slowly, or you can do a cold-water bath to speed up the process.
4) Turn your oven on to “warm”
5) Once the milk hits 115°F /46°C add your prepared yogurt inoculation and stir for at least 15 seconds to distribute the yogurt microbes evenly.
6) Distribute the inoculated milk out between your glass jars, put a lid on them, and put the wired thermometer probe in one of the jars or in a water bath if you’re using one. After, transfer them all to your warm oven to incubate.
a. Using a water bath will always be the better option when making yogurt due to improved temperature stability.
7) Let your yogurt incubate for 5-6 hours at about 110°F/43°C. The temperature range for yogurt incubation is 104-115°F or 40-46°C. The incubation time range is from 3-8 hours. If you incubate at a lower temperature the yogurt may take longer to set. Incubating at higher temperatures will cause it to set quicker but this temperature may kill your bacterial strains.
a. The best temperature is right in the middle. About 110°F/43°C.
b. The best time is also right in the middle, at 5-6 hours.
c. If your temperature goes too high or too low, do not worry! Adjust the temperature as best you can and your batch should still turn out.
d. If your yogurt has not set at a lower temperature and you are already at the 5-hour mark, raise the temperature to around 115°F/46°C and check on it every 20-30 minutes, until it sets.
8) After 6 hours, check the yogurt by taking the jar and tipping it over slightly. You should see that your yogurt has set. Never stir at this moment. If your yogurt has not set, keep going in the oven for another hour or two checking every 30 minutes. The liquid on the top is whey and should not be poured out.
9) Once your yogurt has set, pull it out of the oven and either let it come to room temperature before putting it in the refrigerator or put it in the refrigerator directly to let it cool overnight.