How much headspace in fermenter is too much?

[Gixxer]

Just as an example here, what is wrong with putting a 5gl batch into a 10gl fermenter so you don't have to worry about a blow off tube?

 

[Yooper]

Nothing wrong with that at all. Fermentation produces co2 which protects the beer in the fermenter. The only time it would be an issue is when fermentation is over. Over time, the co2 dissipates and the beer can be susceptible to oxygen and issues related with that (infection, oxidation).

But for short term, during active fermentation +/- 2 weeks or so, it'd be fine.

 

[mtyquinn]

Yeah you should have no problems if you are transferring within a few weeks.

 

[Gixxer]

Well that's good to know. Buying bigger fermenters just gives me a reason to make bigger batches. Wait, then I have to buy bigger fermenters for that batch... Then make bigger batches... I really need to win the lottery!