While Stateside micro and craft breweries concentrating on lower ABV session beers, Scottish brewer BrewDog of Fraserburgh, Aberdeenshire have produced a limited release ale called Tactical Nuclear Penguin. At 32 %ABV it is the world's strongest beer. The beer began life as a 10% ABV Imperial Stout. Then the beer was aged for 16 months in two different whisky cases, and then aged at -20 degrees Celsius (-4 degrees Fahrenheit) for three weeks to reach the final heights of 32% ABV. The freezing serves to do much the same thing as distilling does for spirits; it removes water. The alcohol in the beer doesn't freeze, but the water does, which means you can neatly remove the ice, and then freeze the beer again. This raises the percentage of alcohol, and yes, it also changes the flavor and texture; it's more like whisky at the end than a beer.

The Scottish press has roundly castigated Brew Dog as irresponsible and contributing to alcoholism, but I note that Tactical Nuclear Penguin was only available in very limited release—and cost the equivalent of $70.00/bottle. It's very much a craft brew—the brewery's interest in publicity aside, they went to some trouble to have a beer that would be memorable in terms of the quality of taste and aroma. There's an interesting review here.