I got a Brewferm Xmas Ale from Secret Santa last year and kicked it off on 19 January 2016. It went down to 1018 before bottling on 13 Feb. It ended up in 12 swing top bottles that were also a present, albeit not from a mythological sky fairy.
About a month ago or so, I opened another "trial" bottle and it shot out the bottle like some sort of laval eruption. On that basis, I decided to re-bottle and just dropped the contents of the remaining 8 bottles into an FV, gave the bottles a rinse and a spray of Star San and poured the de-gassed beer back into the bottles using a jug and a funnel. By this stage the SG was around 1010 - so one full percentage ABV point higher - well, assuming that the information from a "guess at 1018" minus a "guess at 1010" gives you something in the ball-park of helpful.
As an indicator, at the time of re-bottling each 500ml bottle of fizzy Xmas Ale filled a 2L jug almost to the point of spilling over, but not quite.
As an aside, there is nothing wrong with the yeast that comes with this kit. I re-used it 2 or 3 times to make very passable kit beers from one can kits plus spray malt / hops.
I was not really a big fan of very strong beers before this experiment and am not dissuaded on the basis of it.
Part of me really want to do a "big" beer like a Russian Imperial Stout or a Barley Wine, but is it a good idea?
