^ I'm guessing it's not just fermented to the high alcohol concentration as-is, but rather he added some crap and some alcohol together that ends up tasting like "good beer" when you add some water and carbonate it. As you pointed out, there are yeast strains that manage around 20% alcohol, but I think that's pretty much the max area you can get up to just by fermenting yeast. This is probably some syrupy, malty flavored crap, some hard/distilled alcohol, and a handful of various other flavorings that form the concentrate.

I'll just stop at the local gas station when I feel like having a couple beers that night. I normally prefer good beer, or at least something darker, but for some reason Miller High Life seems to hit the spot just fine when out riding and camping. They carry that pretty much anywhere, so I'm good to go.