Yogurt, never used to like it. Thought it was slimy. And sour. The funny thing is that it doesn't need to be either of those things. Yogurt can be thick (such as 'Greek' yogurt) and sweet (either by the addition of sweeteners like honey or by culturing it a shorter amount of time).
I'm kind of on a quest. Thickened Greek yogurt, kind of like Chobani or Fage. It's thickened with dry milk or buttermilk and contains lots of protein, making you feel fuller longer. A nice dish with fruit and nuts can really last you all afternoon.
Here I have a pot with 4 cups of milk in it. (Despite all the bubbles this is NOT boiling..its only on medium here.)
I added 2 cup of powdered milk to it.
I'm adding 1/2 cup of honey here. I'm still experimenting. After tasting I thought 1/2 cup was too much for for the 3 hour processing time. It was a little too sweet.
Now the most important part, the milk must heat until it is 180 degrees F. We want to kill all the alternative bacteria in the milk and other ingredients so there is lots of space for the good yogurt cultures to work! We don't want to go too far past 180 degrees. The pot can get messy (don't forget to stir once and a while too).
~~Let me just say a few words here for an important tool--the digital thermometer. I am kind of a gadget minimalist but I've really used my digital thermometer. Cheap. Handy. Works for roasted meats, yogurt, chocolate, frying oil, even rising bread. Awesome stuff.~~
Once the milk has reached 180 degrees it needs to cool. The fastest way to do this is put it in a bowl (or sink) of cold water. Without the water it can take up to 40 minutes to cool the milk down to 90-100 degrees F. In cold water it rarely takes more then 5-10 minutes.
Once the milk goes below 100 degrees you can add in 1/2 cup of yogurt culture and whisk, whisk, whisk. This culture comes from a previous batch of yogurt, a powdered culture you can order online, OR (what I do) buy a quart of name brand yogurt, use 1/2 cup, and freeze the remainder for yogurt days. I find that Stoneyfield Farms has the most yogurt strains in their yogurt--5. To me that's worth the extra money (happy intestines), but any other kind should work too. Also, plain might be best but if they only have vanilla--go for it!
Okay, so you got it all whisked in. Much like sourdough the cultures need warmth and time to break down proteins in the milk. People do this in various ways. Crockpots on low, ovens pre-warmed, a drawer with light in it, electric pads, insulated coolers with a hot water bottle. I've tried a few of these but since a friend gave me her dehydrator I use that. It has a setting (115degrees F) for yogurt.
The next question is how long. There are many ideas about this. It is said that shorter times equal sweeter yogurt. I've also heard the opposite. It's kind of like making chicken stock. So many opinions.
I'm still early in my experiments. I would say though that longer than 5 hours seems to have a souring quality to the yogurt. It's incredibly creamy and delicious but it definitely needs outside sweetening. I have also tried 4 hours (excellent, faintly sour, fairly firm) and 3 hours (sweeter, slick, not firm at all).
I'm not done experimenting. I will say that homemade yogurt has an amazing consistency you don't see in store-bought. Incredibly creamy. You can also control the level of fat and protein. In the future I'll do a report on draining and creating 'Greek' yogurt.