I cooked a beer that came to 1.074 OG and it blew foam through my airlock. I had to rig up a quick blow out valve to compensate for the amount of fermentation that was taking place. This was the first beer I cooked that did this. Word to the wise, if your OG is over 1.060, better hook up the blow out valve to start with!
Quick Homebrew Blow Out Valve Setup
