I have a 25 Gallon SS pot with lid. My friends in I want to make an all grain 15 gallon Pumking clone (which has a huge grain bill). With the dimensions of the cooler we are using to ferment in we cant fit 3 carboys in it, but the pot just fits with the lid. would there be any problems if we kept the pot covered and fermented in that? would pressure be an issue since the lid doesnt snap over the pot. Thanks!