Single Hop 2.5 Gallon Mini Batches

I think I am going to do mini batches for my single hop extract IPAs. More variety, less quantity in case I don't like the batch. I will use this calculator http://www.tastybrew.com/calculators/recipe.html for the calculations. I only have 5 gallon carboys and I have read I cannot rack to a secondary if my mini batches are 2.5 gallons because of the head space O2 issue. Should I just not worry about the secondary and just bottle when fermentation is complete from the primary? Will the beer condition adequately in the bottle?

Leave the beer in the fermenter for 4 weeks and bottle.

So I'm a little confused...


It's okay to have 2.5 gallons in a primary, but not a secondary? Am I reading this right?

Can someone please explain this to me.

Because if this is true, it solves a couple issues I've got with a couple beers and meads that I'm planning.

I only have 5 and 6 gallon carboys, but I would like to do a 2 or 3 gallon batch, for the same reasons that jay29 stated.

If you put 2.5 gallons in at primary, the yeast will use the oxygen, multiply/grow and then start fermenting. The CO2 from fermentation will push any remaining O2 out of the carboy. So it will be fine, just don't take the airlock off...leave it until you are ready to bottle. If you racked 2.5gallons into a 5 gallon carboy for a secondary you would be introducing a lot of oxygen.