Reviving an old thread.
I just started making yogurt again. I was excited about some grass-fed milk I bought, figuring the flavor of the yogurt would be that much better.
Three small, trial bowls later - slimesville
I checked the temperature, babysat the incubation, etc etc.
I’ve concluded it was the milk. The grass-fed milk is ultra-pasteurized, and even bringing it to a boil before cooling it back down didn’t help.
So I bought my regular milk again, and voila - success!
The culture I used is a mix of store-bought yogurt, kefir, and a little each of the slimy batches for variety.
I use the microwave as a sealed incubator overnight - set the yogurt bowl in a larger bowl of warm water (to speed t up), after boiling a cup of water to warm up the microwave.