Ghost Deer is a 28% fermented beer, the strongest ever fermented beer.... After fermentation it is aged for 6 months in some amazing whisky, bourbon, rum and sherry barrels. There is only one Ghost Deer head and this beer will only ever be available on draft, served in a stemmed glass, direct from the mouth of the deer himself.That business about the deer is of course literal--it pours from the mouth of a taxidermied deer head. The release was accompanied by one of the brewery's famous videos, which tells the tale of the ghost deer and manages to advance the brand brilliantly.
All well and good. But here's the thing: 28%?? Can this be? If BrewDog has managed to ferment a beer to that level, it would be a towering achievement. They report using three yeast strains to get there, but I've never heard of any yeast that comes close to tolerating that level of alcohol (White Labs and Wyeast strains top out at 18%). Beer has complex sugars that yeasts have a hard time digesting at final gravity, so even if you found a yeast strain that could go that high, I don't see how it could munch through the maltotriose to get down to that level. It seems to me that if BrewDog managed to create a beer of 28% strength entirely from fermentation, it would represent a radical advancement--one far more impressive than taxidermied deer heads.
Any sciencey types out there willing to shed some light on this? Is BrewDog polishing the apple here, or is it really possible to tease 28% alcohol out of the hardest-working fungi in the beer world?