1/2 a gallon headspace with blow off

Looking for some thoughts on whether it would be sufficient to leave a 1/2 gallon headspace for a 6 gallon malt extract batch while using a blow off tube.

I'll be using a 1/2 ID clear tubing attached to the "nipple" inside a universal bung as a blow off (universal bung: http://www.midwestsupplies.com/small-universal-carboy-bung-drilled.html). The bung is then filled with hot glue (a great idea that was brought to my attention by Masonsjax, in a past post thx).

First time brewer, Jon

Did it work?

I want to do the same thing with my 2.5 gallon batch of Premium Lager in a 3 gallon carboy. I don't know if I am brave enough to try it though. Please let me know how it worked out.

Sorry about the late reply.

Sure did, I suggest to make one of these, cheap and easy. I have used it on at least 5 brews by now and its still holding up.

Having a blowoff tube saved my butt once when brew was about to hit the fan due to a clogged airlock. Let me know if you want some pics, I'll glady help you out.