I have brewed a 4 gal, all grain batch of an amber using my 8gal brew kettle with a false bottom and a batch sparge with pretty sucessfull results (70% effieciency). I want to do another, bigger beer, but I haven't upgraded any equipment. Do y'all reckon I can fit 13lbs of grain in my kettle-as-a-mash-tun and still manage a 4 gal batch sparge? I know I could figure this out myself through simple experimentation, but I was hoping somebody could give an easy answer before I buy the supplys. Any feedback helps!