5 gallon carboy for primary?

[beergolf]

I have done 8 batches so far. I have two fermenters but I also happen to have two 5 gallon carboys that I don't use, since I pretty much leave everything in the primary. Keeping up the pipeline keeps the two primaries busy.

I just had the idea that I want to do some bigger beers like Belgian Tripples or Imperial Stouts that would require longer times to ferment.

I thought that putting the two carboys into service would be a good idea for these brews.

The question is headspace. Would doing 4 gallon batches be about right so I would have enough headspace for these brews? I was thinking about just scaling down some recipes. I don't want to blow beer all over my ceiling.

 

[Scut_Monkey]

Many people ferment in 5 gallon kegs and they typically ferment 4-4.25 gallons to avoid this problem. However, the bigger beers you are suggesting shouldn't take too long in the primary compared to a session beer. My suggestion would be to ferment them in the primary for a week or so. When you have confirmed the primary is done with SG readings transfer to the carboys as a secondary. You don't have to use the secondary but it will open up your primary for another beer.