An email from my sister-in-law, Julie, about making homemade yogurt spawned a journey that eventually led me to A Year of Slow Cooking Blog for directions to make yogurt in a crockpot. On a regular schedule for several years now, I have been making heated yogurt using a yogurt maker as well as unheated yogurt using a direct-set powdered starter and a propagated mother culture, but this is a new method for me. I love its simplicity but, most importantly, the milk is heated to a lower temperature (145°-150° compared to 170°-180° in traditional heated yogurt-making) which helps to maintain more of the milk's nutritional integrity.
Add 1/2 gallon (8 cups) whole milk (raw unpasteurized or pasteurized but not ultra-pasteurized) to crockpot set to low setting. Cover and heat for 2 1/2 hours. (Note: The milk's temp in my crockpot is 145°-150° after 2 1/2 hours.) Unplug the crockpot. Leaving the cover on, let it sit for 3 hours. (Note: The milk's temp in my crockpot is 120° after 3 hours.) Remove 2 cups milk and whisk with 1/2 cup store-bought plain yogurt with live active cultures like Stonyfield or Dannon. Heidi over at 101cookbooks.com recommends Stonyfield yogurt because it claims to have three additional "live active cultures" (making a total of six) including L. Acidophilus, Bifidus, L. Casei, and L. rhamnosus. Add milk and yogurt mixture back into milk in crockpot and stir to combine. (Note: The milk's temp in my crockpot is 113° after adding the refrigerated store-bought yogurt.) Put lid on crockpot and wrap with a heavy bath towel. For additional insulation, I chose to wrap a quilted mattress cover around the towel. The elastic edge folds over to enclose it in a tidy package. Let it sit for 8 hours. If you normally go to bed at 11:00, start the yogurt-making process at 5 p.m. and it'll be ready to rest overnight wrapped cozily in its covering while you sleep for 8 hours or so. You'll have fresh yogurt waiting for your breakfast. (Note: The milk's temp in my crockpot is 93°-96° after being wrapped for 8 hours, so you can see it has held its heat very well.) You can save 1/2 cup of the present batch of yogurt as a starter to make the next batch, if you like, but the strength of the cultures decline after several batches then you need to go back to adding 1/2 cup store-bought plain yogurt. My yogurt maker's instruction booklet says "no more than 5 consecutive generations because the active cultures in each successive batch will diminish over time." This yogurt isn't as thick as store-bought yogurt, but you have two options. 1)Toss out preconceived notions about what yogurt "should look like" and enjoy every bite of its amazingly fresh, unadultered state. (Stonyfield adds pectin for thickness.) 2)After chilling, strain the yogurt through a cheesecloth-lined strainer placed over a bowl in the fridge to collect the liquid byproduct (whey), then whisk it briefly. The end result will mimic the thickness of Greek yogurt. Don't toss out the whey. Use it in your smoothies. Dick's and my favorite way to eat homemade yogurt is to top 1 cup of it with one diced apple, 1 tbsp raisins, 1 tbsp finely chopped walnuts, and a generous sprinkle of cinnamon. We eat this most every day.
