Today, after finishing milking I did a batch of yogurt. It really isn't difficult and I took a few pictures and will try to explain how I do it.
I save a half cup of yogurt when I make a batch as the starter for the next batch. I freeze it if is going to be a while before I make another batch. I took this out of the freezer last night and while I am prepping for the yogurt, I set the starter in a dish of warm water to take the chill off it. The first time I purchase store bought plain yogurt. I used Chobani plain greek yogurt this time. i have also used Dannon regular plain yogurt. It does not turn out quite as thick.
I Pour a half gallon of whole cream raw milk into a saucepan and put is on medium heat. I stir it occasionally with a metal spoon to avoid having it burn on the bottom of the pan. I use a dairy thermometer to monitor the temperature. I heat it to 140 degrees. A lot of recipes say you have to heat it to 180 degrees and others say not over 120 degrees. 140 degrees works well for me. Once it reaches 140 degrees, I turn off my electric burner and leave it for 10 minutes. It usually holds the temperature for that long with the heat left in the burner.
After the 10 minutes I set the pan in a sink with very cold water. I continue to stir it. With my dairy thermometer I watch the temperature. I want to get it to 112-115 degrees.
While waiting on the milk I put my starter yogurt in a half gallon mason jar.
And I half fill my 2 gallon cooler with 115 degree water.
When the milk has cooled to 115 degrees I pour about a cup of milk into my jar with the starter and wisk it together. I then add the rest of the milk and wisk that.
I put on the lid and immerse the jar in the warm water in the cooler. It should completely surround the jar but not be up to the lid. You may have to remove or add water to get it to the right level. Work quickly through these step to maintain the 115 degree temperature. Cover the cooler. I then wrap two heavy bath towels around the cooler and place in a warm spot. This is by a register in my laundry room. In warm weather it can be left anywhere were it won't be disturbed. Then the hardest part for me is remembering to come back in 6 hours to check it.
I always set a note on the kitchen table as a reminder. You could also set an timer on your stove or an alarm on your phone. After 6 hours I take the jar out of the cooler and place it in the refrigerator overnight.
And this is my end product. I put it into two containers and use them one at a time. I also save out my 1/2 cup of starter for my next batch so I don't forget. We really like the taste and texture of our yogurt. We eat it plain, or add fruit and maybe some vanilla, maple syrup or honey, or use it in a fruit smoothie. All are delicious. I know if you search for methods online you find all different temperatures, lengths of time and additions to add. I have tried adding some dry milk and a tablespoon of sugar to my milk but I don't see a big difference. I have not tried making it without heating the milk above 112 degrees first. Some recipes say to get the milk only to 110-112 degrees and no more to save all the benefits of raw milk. I have not tried it that way, but I don't do the 180 degrees and it is still working well. I have also heard if your yogurt is too thin you can strain it through cheese cloth and drain off some of the liquid. i have not done that either.