Homemade yogurt - troubleshooting
Whenever I make yogurt it comes out grainy. On-line searches suggest that not mixing the starter in thoroughly could be the culprit, so I make extra-sure to do that well. It hasn't made a difference. I've used skim or 2% non-homogenized milk, and tried it once with homogenized. I've used several different yogurts as starters, including the powdered stuff.
I heat the milk until it starts to boil, boil it gently for a minute or so, then let it cool to just below 100 degrees F. I use a yogurt machine (My oven is very sad and old, no oven light and poor insulation) and I incubate it for as long as the machine recommends - 6 hours for whole milk, 8 hours for skim, so I recently did 7 hours for 2% milk.
I have noticed that the whey has already separated when I turn off the machine. Am I possibly incubating it for too long? If so, what should I look for to tell me it is done?
Thanks for any advice you can give. I am about at my wits end! I love the yogurt (nice and tangy and slightly runny, which is exactly how I like it) but the texture is pretty bad.