[GrainSpiller]

Hello,

I just joined the AHA a couple days ago and have been brewing 5 gallons batches for some time now.  A few friends of mine and I are planning to get together to make a couple 2.5 gallon portions, but my primary concern is will I run into any issues if I ferment 2.5 gallons of wort in a 6 gallon fermenter?  Would it be exposed to more oxygen over time?  Also, does the fermentation process end sooner for a 2.5 gallon batch than a 5 gallon batch would?    Never did this before, so any help / advice would be appreciated.  Thanks.

[a10t2]

You'll have no problems with the extra head space, and if the pitching rate is the same then fermentation will take roughly the same amount of time.

[GrainSpiller]

Thanks for the info a10t2.  I appreciate it.   

[kuphish]

You'll have no problems with the extra head space

Agreed.  I've brewed half batches in my 6.5 gallon fermenters with no ill effects.