Okay, before getting into the method of making yogurt, let me first explain the use of an oven in this process. At the end of the whole process of making yogurt, you incubate it in the oven overnight (or for 8+ hours during the day like I am right now) WITH THE LIGHT ON. No heat, just crock in the oven with the light on to maintain warmth.
Well I got a new *used* oven in December when my old one started sparking when I turned on the light. Not good for my yogurt. Unfortunately, this oven (that I bought from someone in town who posted it on facebook) doesn't have a window, and thus, doesn't have a light switch. So after a few weeks of not knowing what to do about that and I finally had a bit of a pregnant emotional meltdown needing my yogurt breakfasts back (store-bought yogurt just isn't good anymore), my husband got creative for me.
He drilled a hole in the lining of the door to allow the rod controlling the light to pass through. When the rod passes through the hole, the light doesn't turn off.
And when I'm not needing the oven light on (any time I'm not making yogurt), we plug the hole with a cork, purchased at our local hardware store.
Hooray for a MacGyver husband and hooray for making yogurt again! And simple breakfasts and sanity returned!
So then, here it is (as learned from Girls' Guide to Guns and Butter, which I am sad to learn no longer exists! But give credit where credit is due.):
1/2 gallon milk (as fresh as possible! Not close to expiration date!)
2 T yogurt
You'll need to buy the yogurt the first time, but then you can save 2 tablespoons from the old batch every time you make a new batch. I only ever buy yogurt now if I forget to save some to start the new one. Also, I have tried this with full fat cow's milk, and soymilk. I've been making soy yogurt for my family for almost 3 years now. I haven't tried any reduced fat milks because Girls' Guide said not to. She's Albanian or Armenian (can't remember which) and grew up making yogurt because you don't buy it in a store there. So I'll take her word for it. One more note and then I'll continue: I make a double batch and it works just fine for me. We go through it pretty quickly and even when we don't, it still last several weeks.
*I always start this early in the morning, just any time before lunch.* Pour your milk into a crockpot and heat it to between 180 and 190 degrees. Girls' Guide said you have to do this to kill certain enzymes that prevent the good bacterial growth, but if you go hotter than 190 you fail. In my crockpot, it takes 2.5 hours on high. I also have a digital crockpot with probe thermometer, so I don't have to monitor it. It just beeps when ready.
Once your milk has been heated to the right temperature, it needs to cool down to between 105 and 111 degrees. The amount of time that takes varies so much, depending on what your room temperature is, and whether you leave the lid on, off, or cracked. Sometimes I need it to cool quickly, so I leave the lid off. That usually means I'll have a dried film on top of the milk that needs to be skimmed off, or pulled off with clean fingers. If I'm not in a rush, I'll leave the lid on and check it several hours later. If you go cooler than 105, I've still been successful with my yogurt when I heat it back to between 105 and 111 degrees. Yesterday's yogurt was pretty much a fiasco. It should've been done this morning, but didn't get into the oven to incubate until this morning. Ugh! We'll see how it turns out.
After heating and cooling the milk, it's time to spend 5 minutes prepping the milk for incubation. If there's a film on top, scoop it off before proceeding.
Scoop 2 cups worth of milk from the crockpot. (I never measure this anymore. I just dip Will Smith in and call it good.)
Add your 2 T yogurt to the reserved milk. (Mine is 1/4 cup because I double the batch)
Combine the yogurt in the warm milk with a whisk. ***Now here's something important! Girls' Guide says it is suuuuuper important not to stir in a circular motion. When doing yogurt or cheese (anything curdling milk), you must stir SIDE TO SIDE and UP AND DOWN. I don't remember her explanation, again, I just trust that she knows her stuff. She was born doing it.
Once the yogurt is combined in the reserved milk, pour the milk back into the crockpot and stir. SIDE TO SIDE and UP AND DOWN. Say it with me!
Then put the lid on the pot, put a kitchen towel over the lid, remove the crock from the heating element of the slow cooker unit, and place it in the oven overnight. Oven off, light on. Seriously, the light is ESSENTIAL. I've failed my yogurt a number of times by forgetting to turn the light on.
It sounds complicated, but I promise you, it's not. It's really very simple, and takes 5 minutes of my time. We love this stuff and I really wish Girls' Guide was still active because she explains it so much better.
Fast forward 8 hours--my kids LOVE having warm yogurt for breakfast! It will be warm still when you pull it out of the oven in the morning. It's delightful, and when I was pregnant this last time, I had a serious aversion to anything cold, so warm yogurt days were the only times I got to have my yogurt parfait with
crockpot granola. Anyway, the longer the incubation time, the more tart the yogurt will be. It's quite sweet with a shorter (but still at least 8 hours) incubation time. It will possibly have a yellowish liquid floating on top of the thickened yogurt.
That liquid is the whey. You can stir it back in and have a thinner yogurt, or pour it off. I pour it off and use it for various things--bread, plant vitamin water--as read from
The Prairie Homestead.
After we eat breakfast, I simply pull out my canning jars and funnel and store the leftovers in the fridge.
Girls' Guide said you can add flavoring into the milk when you're heating it, such as fruit purees, honey, jam, etc. I haven't tried any of that. I keep my yogurt plain because I use it in cooking--in my pizza dough, smoothies, as a sour cream substitute, etc. I've also taken this batch of yogurt and strained it through a colander and kitchen towel over a pitcher (I'll have to make a post for that too, I guess) to make ricotta cheese for lasagna. Plain works best for me, and I may never experiment with flavors. Unless you ask me to. Then I will. Because I'm an experimenter.
I think that covers everything! Shoot me any questions if anything was unclear. I still have severe Mom Brain, so I'm crossing my fingers that this works for those who asked for it!
UPDATE 3/24/2018: I don't think I've ever mentioned, but I make soy yogurt. We have dairy allergies, so I make our yogurt with soymilk. 8th Continent, Kroger, and Great Value brands work well for me. Silk sucks. It just turns out awful every time.
