Me personally? Experience from my (much) younger days says somewhere between 1/2 gallon and 1 gallon - though unplanned eruptions sometimes occured when nearing capacity.

As per homebrewing - I've got 15 12-bottle cases of 22-oz. bottles, 3 primary fermenters, 4 secondary fermenters, and 3 five-gallon kegs. If everything was full at once, that's a little over 80 gallons of beer.

I've only brewed 50 gallons in 7 varieties so far, so I've got plenty of spare capacity. At my usual consumption rate of two 22-oz. bottles per day, 50 gallons would last me 5 months - but sharing it cuts that time down, of course.

I'll brew all winter and try to have most everything full at the end of March - when my attention turns to fishing and other things. Then that'll carry me over until cool (brewing) weather next year.

Moderate, downright moderate.