5 gallon batch - ok to secondary in a 6 gallon carboy?

The local LHBS's beer kits make 6 gallon batches, so I always make that format. I ferment in a 30L (~8 gallons) bucket, and then rack into a 6 gallon carboy. This works very well for me, as I don't have to worry about jammed up airlocks etc, and it leaves relatively little headspace in the carboy once racked.

For my first partial mash, I took a recipe I found here which was for a 5 gallon batch. I decided to ferment it directly in my 6 gallon carboy. I reasoned the good amount of headspace would leave enough room for the krausen (which it did), and the space would eventually be filled with CO2.

I know it's not strictly necessary, but I do like to secondary my beers.

My question then: if I rack this batch, I'll have "1 gallon" of headspace filled with air. Should I be worried?

I would suggest a blowoff tube in a bucket of water. If you get a large amount of krausen it will plug up your airlock.

Ideally, you want the smallest amount of headspace in your secondary if you are going to be doing any bulk aging. When you rack, the beer will likely off-gas some CO2 so there will be some blanketing across the surface of the beer.

Personally, I'd just leave it for an extended primary and forgo the secondary/bright tank altogether.

schweaty said:

I would suggest a blowoff tube in a bucket of water. If you get a large amount of krausen it will plug up your airlock.

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If I read it correctly, he's using the 6 gallon as a secondary.. so blowoff isn't needed.

As flyangler said you should be alright within a reasonable timeframe, as some co2 will be roused out of solution (as well as a bit more produced) when you rack. It should make a suitable blanket of CO2. Ideally you'd just want to leave it alone, but if you need/want to get it off the cake I don't see why you couldn't.

it wont matter. if your rack properly (not exposing the beer to air on its way from primary to secondary) the beer will off gas plenty of co2 to fill the head space and the yeast will be woken up and produce more. you shouldnt need a blow off unless you plan on adding fruit or something in the secondary.

Thanks for the quick answers everyone.

I know some would argue against it, but I there's always a half inch of extra crud that falls to the bottom of the secondary which I assume can only help to clarify my beer. I guess a longer stay in primary might negate that effect, though.

I usually secondary after 7 days (weekend hobby), although this one's going on 2 weeks.