6 gallon better bottle needs about 12" depth, 24" high with airlock. All mini fridges seem to have the hump on the bottom back with a 45 degree angle at the corner/edge. You'd have to build a small shelf so it would clear the hump. The one I found in the trash, and later ruined by overbending the freezer "shelf", also required me to remove the plastic panel on the back of the door to remove the molded in shelves. After that, it would fit.