I'm making a 5 gallon batch of mild in a few days (og 1.036) that will be fermented in a 6 gallon better bottle. The LHBS doesn't carry fermcap, so I'd have to order it and wait another week to brew. If I don't need a blowoff tube I'd just brew now without the fermcap. Is 1 gallon of headspace enough for a 1.036 beer? (btw, I'll be fermenting around 67 F).