Any ideas? Perhaps I'm incubating for too long? How long does yours take to turn to yogurt.
Any good yogurt starter culture recommendations?
There are two types of yogurt cultures mesophilic cultures that are meant to culture at 70-78 degrees and Thermophilic cultures that are meant to culture at 110 degrees. The yogurt you buy in the store is made with a thermophilic culture so it's happiest at 110 degrees. Anything above around 115 can be a problem and you could have the same effect. Yogurt (and cheese for that matter) can be a bit temperamental in terms of temperature. Too high or low causes problems.
I agree - your heat was probably too high. Or it cultured for too long.
The liquid is whey - you can use it to culture your next batch, or soak grains in it.
Drain the "yogurt" in a sieve, or a colander lined with a clean cloth or paper towel. Let it drain at room temp for about 12 hours, until the whey has drained out and the curds look like cream cheese. Stir in some salt ... and it's yogurt cheese!