I used a crockpot that a friend gave me and used a basic meat thermometer to check the temperature of the milk, so I wouldn't have to watch the clock and guess about when to do the steps of the process. It's so simple its amazing! I bake gluten free, and have found that using yogurt in recipes really helps moisture, flavor and texture. I use it all the time. Not to mention living on yogurt during my most recent pregnancy!
Now I have a real candy thermometer to check the temp of the milk, (and six kids who like yogurt and my pancake recipe), and this is what I've been doing:
Homemade Yogurt in a Hand-Me-Down Crockpot:
3 quarts whole milk
a heavy bottomed pot
an old school crockpot
a few tablespoons of yogurt with live active cultures
a beach towel
I have found, and you will read in a lot of other places as well, that whole milk is easiest to make yogurt with. You can use reduced fat milk, but, really, milkfat is not so bad for you after all, and until you are used to it, it's advisable to just go ahead and use whole milk to ensure a delicious result, because for some reason it helps with thickening.
All you do is heat your milk in a pot on the stove until it reaches 180 degrees F. This is necessary, so make sure it gets that high. Use a quality, heavy bottomed pot so you don't burn the milk. Also, don't go far, because it's a pain when the milk boils over and you have to clean the top of the stove. I should know...
I pour the hot milk into my clean, unplugged crock pot. Crock pots are excellent for yogurt because they hold the heat so well, with the thick crock itself and the insulated base. My crock comes out of the base, and I like to have it out when I pour in the hot milk, because the next step is to allow the milk to cool. Leave it uncovered until it comes down to 115 degrees F. (Make sure its less then 120 or the heat will kill your live yogurt cultures.)
When the milk has cooled, add a small amount of the warm milk to your reserved yogurt, full of live cultures. Blend, then add it all back into the milk. At this point, we want to hold it at this temperature so the little cultures can do their thing. Put the crock into the base, still unplugged, put the lid on, and cover with a substantial towel to really hold the heat in.
I read something in the past about how long to let it go, and that more hours of activity would allow the live cultures to use up more of the milk sugar, lactose, and would result in a more sour yogurt. So, I used to let it go only about 6-8 hours. Since then, I have fallen in love with Greek yogurt, and have found that longer times lead to thicker yogurt, so I leave it overnight. So does Auntie Leila. See what you like, and decide how long you want to let it go.
I love Greek yogurt, but I have not found it to be important to use Greek yogurt for culture. To make it "Greek" you have to strain it through cheesecloth over a colander afterwards to remove the whey. I can't see me taking that extra step, nor throwing away whey! (I suppose you could save it to use as buttermilk.)
It does make a big difference if you spend the money on a bit of really nice, organic, natural, live yogurt for your starter. After that, you save a little of what you made to use for the next batch! Awesome! Easy!
And then, I discovered Australian yogurt. 'Noosa' is the brand my husband found at the store here, and it is so delicious, it's like a dessert. So. Delicious.
I agree with this review, and nice pics, too.