Brewing 10 litres in a 25 litre fermentation vessel?

Question

I'm a novice and have just started home brewing from a complete starters kit. The kit came with 2x25 litre fermentation vessels and a kit that makes 20 litres.

I've been looking at some beer kits which brew 10 litres, and I'm wondering if it's okay to brew them in the 25 litre fermentation vessel - does it make any difference, or should I be using a smaller vessel? I don't know if lots more air being in the vessel would make the brewing more difficult (eg. would it be harder to control the temperature?)

Any advice is greatly appreciated. Thanks!

Answer 1

It'll be fine - the thermal mass of a few extra liters of air is insignificant. Once fermentation starts, all that air is pushed out and replaced with CO2, so contamination is not going to be a problem either.

On the plus side, you've got plenty of headspace for a vigorous ferment!