I'm thinking about investing in a keg, etc. done some reading but still have a lot of questions. I currently bottle from brew cans which fill the fermenter to 23L and comes out to about 30x 750ml bottles (22.5L).
I have seen many different size kegs. Does it matter the size? Do you need to leave space in the keg for gas/air or is this bad?
For example I saw a 30L keg for sale 2nd hand. Could I brew 22.5L in this 30L keg?
Also saw 18L kegs - if I got two of these kegs could I fill each with 11L? If I got one could I fill it to the brim (18L) and bottle the remaining few litres?