Hi all. I got a 5 gallon food grade bucket from Lowes for my fermentation bucket. 5 gallons of liquid puts it about an inch below the lid. How much "breathing" room does the fermentation process need above the liquid line? Can I just split into two buckets of 2 1/2 gallons each and split the yeast between the two and expect good results? Is it ok just to put 4 1/2 gallons in for the fermentation? I'm brewing an American Ale from Northern Brewery. I couldn't find any bigger buckets locally.