you havent made chelsey buns?!?!?! man you havnt lived if you havnt made them before!!!! nah seriously though the yeast rises with warmth and from my understanding (probably wrong) IF YOU DONT USE A stabaliser (baking soda) it possibly will rise and put a whole pile of crap into your tank. I only know this coz it has happend to a few people I know that have diy co2 and the compression on the bottle squeezes everything into the tank.