I don't think you can get 55% beer from natural fermentation? Somewhere around 10% was the max I thought.
Wonder what process was used to boost it to 55.
Correct, or at least with traditional brewing yeasts. You can use champagne yeast to increase abv to about 14% or so.
If you freeze brew and then remove the ice, you can inflate the abv to some serious numbers - you are removing water and leaving the alcohol in greater proportion to the liquid volume remaining.
Oops, didn't read the prior posts - asked and answered, silly Fatman.