Making yogurt is a simple process...you just need a good thermometer, a bit of patience, and some existing yogurt to use as a starter. I made this batch with whole milk since we normally only eat small amounts and we use it to accompany many of the rice dishes we eat, but you could use a reduced fat milk instead. Homemade yogurt is thinner than store bought varieties because they normally have pectin or gelatin added to thicken them. You can add about 1/2 cup of powdered milk to act as a thickener if you want a firmer consistency.
1 gallon whole milk
1 cup plain yogurt, organic would be best and try to find one without gelatin added
Over medium low heat warm milk to 185 degrees. The milk should not boil and you should stir from time to time. Remove from heat and allow milk to cool to a temperature between 108-112 degrees. I normally fill the sink with cold water and place the pot in the cold water.
Next, stir a little cooled milk in with the existing yogurt to loosen it a bit and then add the mixture to the pot of cooled milk. Stir. Place cover on pot and wrap in a blanket. Place in a warmed oven (I turn my oven on for a few minutes to warm it and then turn it off. Then I turn the lights on inside for a little warmth. Place the wrapped pot in the oven...just make sure you turned it off...please! Leave alone for 6 to 7 hours or until set. Place in containers and refrigerate.
If you are not comfortable with the blanket in the warm oven trick...you could use a heating pad or electric blanket...which I don't own, but I think they would work well. You are just trying to keep the yogurt at about 100 degrees or so for the entire time.
Also, if you keep the milk at 185 degrees for around 30 minutes you'll have a thicker end product...something to consider, I just don't normally do this.