I have a chest freezer that I want to use to control fermentation temperature, that I'm hoping to use to with two five gallon beer batches. Unfortunately, the bottom of the freezer has two levels, making it impossible to load two round carboys into the freezer at the same time. There is plenty of space for the beer volume if I can get a carboy of the proper dimensions.
Is is possible to a make a custom carboy shaped to use the space more efficiently? Can plastic sheets of the same type used in carboy buckets be purchased easily?