Hello I am new to homebrewing and I should have done more research before I bought my primary fermenting carboy vessels. I found a great deal on 5 gallon glass carboys and I went ahead and purchased 4 of them. I went to the local homebrew store and the owner informed me that I could not ferment a 5 gallon recipe in a 5 gallon carboy. I understand that the fermentation process will produce foam and I would have a blow off. So I bought a cheap fermenting bucket to do the job. I am disappointed because I wanted to watch the process through the glass and I don't really want to buy a 6.5 gallon glass carboy. What can I do to use the 5 gallon carboys? It is as simple as using a ratio to factor each of the ingredients to make a 4 gallon batch instead of 5 gallons, in the carboys that I already have? This would allow for the additional space for the foam and not run the risk of spillage. If anyone has the answer to my dilemia please inform the newbie. Thanks