Using 5 gallon glass carboy for primary fermenter

[Kevin J]

What size of batch can I use in a 5 gallon primary fermentor?
How much head space is needed?
Thanks!

[MaltLicker]

Four gallons in a five-gallon carboy is my norm.  Level is usually right above the top raised-line near the shoulder.  

I've started using a blow-off tube every time, even with typically low-head yeast.  Got tired of cleaning airlocks.  

[Maine Homebrewer]

I would purchase a 6.5 gallon carboy and use the 5 as a secondary.

Either way you most definitely should use a blow-off tube.

[Bootlegbrewer]

Four gallons in a five-gallon carboy is my norm.  Level is usually right above the top raised-line near the shoulder.  

I've started using a blow-off tube every time, even with typically low-head yeast.  Got tired of cleaning airlocks.  

+1

I usually try to use a blow off tube or one of the single bubble fermentation locks. The double bubble fermentation locks were always problematic for me.

[SETTERDOWN]

Why the carboy for primary?  I have always used it as secondary?  Just curious..  I really like the bucket let off especially when building something stout..... would hate to see a serious blow off and detonation of quality beer with only one chance IN THE CARBOY. (BEEN THERE DONE THAT.)

Thanks Ryan.