I started making yogurt about 25 years ago, and took about 5 years off. During that time, they have ultra-pasteurized everything in the grocery store. I never used to have to strain to get good, thick yogurt, with plain old "organic" milk. Since I've started making yogurt again, since I won't buy ultra-pasteurized anything, I have found non-homogenized, low heat pasteurized, grass-fed milk that is affordable. And, it makes thin thin milky yogurt that I have to strain. I measured this last time, and I strained off 5 cups of whey, leaving 3 cups of barely thick yogurt. I'm not talking thick greek yogurt that I ended up with, but just almost as thick as what you can buy at the grocery store. I even bought a yogurt-maker, thinking my ancient heating pad might not be living up to maintaining heat anymore. The whey is fine, and we'll use it, however, I really don't need 5 cups of it every time I make yogurt, and I'm constantly trying to figure out something to do with it, because no one really likes it :( And, it makes the yogurt much more expensive.
So, I warm my starter yogurt to room temp or slightly warmer in the yogurt maker. I've been buying starter yogurt each time, since I can't seem to get a good thick batch of yogurt going to start with. Should I buy dried starter? Would that make a difference?
Then, I heat the milk to 180, cool in an ice-bath to 110. I have started using a thermometer, since I"m having so many issues. I mix a bit of the milk with my starter yogurt, then mix it all in together and put it in the yogurt maker. I've tried any time frame from 8-24 hours. Longer makes it very sour, but not substantially more thick.
Any ideas to help me? I'm close to throwing in the towel.