Originally Posted by district_davis
and on the kettle lid.
This part worries me a bit. What are you doing with the kettle lid on the pot? Don't boil with the lid on. Boil with the lid off to drive off all that DMS.
I also use Fermcap-S (or equivalent) and rarely have boil overs. You absolutely have to watch the pot like a hawk when the boil is about to start, and for a couple minutes after that. It's just the nature of all the sugar/starch/protien in the wort that is going to cause lots of sticky bubbles and you most likely will have to stir/blow/spray them down at least a little bit until the hot break happens. Once that happens boilovers are much less likely to happen.
Fermcap-S is also helpful in starters to keep the krausen under control on the stir plate in the flask.