My yogurt turned out fantastic!! I learned the secret, I believe!
I heat the milk up to about 125 degrees, let it cool to 115-120 degrees, add the culture, stir gently but well, pour into the glasses, put lids in place, then place them in my ($1.50 thrift store) yogurt maker then put the lid on.
This is what I've always done, but most of the time the yogurt would be runny on top, firm on the bottom.
So this time I set my heating pad on low and placed it on top of the yogurt maker, then covered it all with a towel.
It turned out perfect. Absolutely perfect consistency through and through. It is still thinner than store-bought because I don't add thickeners, but that can be remedied by straining out the whey through a tea-towel and collander. Nonetheless, you can stand a spoon up in it!
The flavor is very very tart. I could probably culture it for less time and get a milder flavor, but I like a nice sharp yogurt!
Now I need some cucumbers to eat it with!