Earlier quoted context omitted.
> It’s also nice and strong - 9% iirc As all good stouts should be, in my humble opinion! My all time favourite beer is the BrewDog, Nogne and Mikkeller collaboration stout: the Black Tokyo Horizon. It's 17.2%!
17.2%?!? That led me down the rabbit hole to find out beers with very high alcohol content. Apparently Brewmeister Snake Venom, at ABV 67.5%, is the highest.
The highest you will see actually fermented is usually around 18-20%, but there are specialty yeasts that can get up to 25%. Then you can get even higher with extended aging in spirit barrels where some ABV is picked up by absorbing residual spirit as well as evaporation increasing the strength. Sam Adams Utopias for example comes in at 28%