It may look daunting to make your own yogurt, but it is relatively simple. In the beginning, you need to keep an eye on the temperature, but mostly you just have to wait and give the cultures time to ferment. Other than the yogurt culture, the most important ingredients are time and temperature. You need 8-10 hours to incubate the yogurt in a warm draft-free environment, and an additional 8 hours in the refrigerator to finish. Once these steps are complete, you can eat it right away or strain out some of the whey for Greek-style yogurt.
Because there are only two ingredients in yogurt, use the best quality milk and yogurt you can buy. For best results, the yogurt used as your culture must contain real live cultures and no fillers, gums, or artificial ingredients. I use Fage and Dannon yogurt whenever I start with a new yogurt culture.
Seek out organic milk that is not ultra-pasteurized as this process kills off important and healthy bacteria needed for making yogurt.
You can use your homemade yogurt as a culture for up to 3-4 generations. After that, start over with a new batch of yogurt bought at the grocery.
This recipe scales up to 1 gallon of milk with ¼ cup (65 ml) fresh yogurt culture.
Yield: Makes about 7 cups (1 L 750 ml) yogurt before straining out the whey.
Serving size is a half a cup (125 ml)
Pour your milk in the stock pot and set the burner between medium / medium-high.
Slowly, heat the milk until it reaches 185°F / 85.5°C without stirring. Any temperature at or slightly above 180°F (82°C) but below 195°F (90.5°C). You do not want the milk to boil or be too hot and kill off the important yogurt-making bacteria.
Turn off the heat and remove the pot from the stove. Let the milk rest until it cools down to 115°F (46°C). I allow my milk to cool on the counter and stir it every now and then to help release the steam. I set the timer to keep track of the time and check the temperature frequently. This process can take around 35 minutes, give or take.
A faster method of cooling the milk is to fill a large bowl partway with ice and cold water. The bowl needs to be large enough to accommodate your stock pot with ice water surrounding the bottom and partway up the sides of your pot. A sink will work as well. Stir the milk in a back and forth manner every now and then until it is cool. Remove the pot from the ice bath when it reaches around 118° – 120°F (48° - 49°C). Place on the counter and keep the instant-read thermometer in the milk so you do not cool the milk below 115°F (46°). If the milk does fall below 115°, place the pot back on the burner and heat it up 115°F (46°C).
Add one ladleful of the 115°F (46° C) milk in the bowl with your starter yogurt. Whisk the yogurt mixture until well incorporated then pour the yogurt culture in the pot with the milk. Stir then cover. Place the inoculated milk inside a draft-free and warm space.
Place your yogurt culture in a warm draft-free place. In my house, my oven is the best spot. Keep the oven warm by keeping the oven light on. I found it does not always work if I let the yogurt incubate on the counter. According to Cheryl Sternman Rule in her book Yogurt culture, the ideal temperature for incubating yogurt around 100°F (38°C).
Allow the cultured milk to incubate for 6 – 10 hours. Sometimes, it takes longer, up to 12 hours, but the consistent incubation time is around 8-10 hours. The yogurt is done when it looks thick and solid with some liquid, the whey, sloshing about when you jiggle the pot. It will look like plain yogurt.
One final step before eating your yogurt is to chill it in the refrigerator for several hours. Tip the yogurt in a bowl and tightly cover with plastic wrap or a tight-fitting lid. Add the yogurt to the refrigerator and chill for 6-8 hours or overnight. This extra step develops more flavor and a creamier consistency.
Voiá, you just made yogurt!
Before you use up your yogurt, measure out 2 tablespoons (30 ml) to ¼ cup (60 ml) of yogurt and place in a bowl with a tight fitting lid. Label and date the yogurt. You will use this yogurt for your next batch of yogurt. Store in the refrigerator for up to 7 days. Taste before using to make sure it is not starting to turn. You can get 3-4 generations of yogurt when using starter from homemade yogurt. After that, start fresh with a new batch of yogurt from the grocery store.
Scrape the yogurt into the lined strainer. Draw up the four corners of your cheesecloth or towel and bring them together. Tighten them close to the yogurt and tie with a string or twisty. Place the bowl with the colander in the refrigerator and drain the yogurt until it reaches the consistency you desire. The longer it strains the thicker it gets. I like the consistency after straining for 3 hours.
If your yogurt is thicker than you like, add some of the whey back in to loosen it up.
Yogurt dries out inconsistently throughout the incubating and straining process. This creates some lumpy spots in your yogurt. This is normal. If you want smooth yogurt, spoon out the amount you want then whisk it right before using. Whisking the yogurt will make the yogurt looser, but it gets out the lumps.
Whey
Don’t throw out the whey. It is great in many recipes and for marinades. Use whey in any recipe calling for traditional yogurt, not Greek yogurt, or milk like in baked goods, pancakes, and bread. Whey is acidic, so it will activate the baking soda. Use in smoothies. Use as a tenderizer for meats and in marinades. Whey will last in the refrigerator for up to 2 weeks.