Just a tip on yogurt-making (and I've only tried this with goat's milk,
never soy):  Make sure your milk is about 100 degrees and pour into a
wide-mouth thermos (whatever size you need) after mixing in the
starter.  Put on the lid and wait 4-6 hours.  Mine came out perfect
every time and I didn't have to check it until after 4 hours was up!