brewing a 5 gallon batch in a 5 gallon fermentor

I feel like this is a dumb question, but here goes.

I usually brew in 5 gallons in a 6 gallon fermentor and have a bit of headspace where the krausen usually forms.

I was reading the benefits of not transfering your beer to a secondary frementor and just letting the beer ferment and age in one vessel. I want to try this out but I have one secondary (5 gal) and one primary (6 gal)

So is it ok to fill a 5 gallon to the top with wort and pitched yeast leaving no headspace for the krausen to develop. I of couse will be using a blow off tube and then replacing with a fermentation lock when the krausen dies down.

Thoughts?

i would just scale the recipe down 1 gallon.

You could probably expect a good size mess during fermentation, there is a lot of goop for a better word that will come out of the blow off tube. The headspace is important to me for the ease of clean up. Give it a go and let us know how it works.

As a side note All of my carboys are 6.5 to 7 gallon for that reason. I sold all my 5 gallon carboys on Craigslist, You'd be supprised how many people want a carboy of any size!

yeah, I'd just scale the recipe back, rather than lose money through blow-off loss due to wasted ingredients.

that or make wine/mead in the 5gal carboy, since these don't really krausen up like beer (usually)