To the best of my knowledge, there are two main organizations which provide beer style guidelines. The Brewer's Association (BA) provides style guidelines "as a reference for brewers and beer competition organizers." The Beer Judge Certification Program (BJCP) uses a similar set of guidelines, but there are some differences from the BA's guidelines. For my purposes they are similar enough, so I am going to use the BA style guidelines for my comparison.
The first think I noticed while looking at the BA style guidelines (which you can download from their website from the link above) was that there wasn't an entry for American Strong Ale. The closest I could find was English Strong Ale. The description of English Strong Ale is close, but doesn't quite accurately describe Stone's Double Bastard or Arrogant Bastard Ales, due to the aggressiveness of the hops used in the beers. American Strong Ales must be considered "Out Of Category", which doesn't do me much help. Basically, all that it tells us is that an American Strong Ale is an American style, high alcohol beer which doesn't fit into the barleywine, old ale, double IPA categories.
According to the BA, an American Barleywine is amber to deep copper in color, a full bodied 8.4-12% ABV, and can be anywhere from 60-100 International Bitterness Units (IBUs). The high hop bitterness is balanced by fruity esters. Some examples of American Barleywines are Sierra Nevada Bigfoot and Avery Hog Heaven Barleywine.
|Picture from www.sierranevada.com|
|Picture from www.averybrewing.com|
The BA describes Old Ales as dark amber to brown beers that are medium to full bodied, ranging between 6-9%. They typically start between 30-65 IBUs. There shouldn't be aroma from the hops, and minimal to medium in the flavor. Instead, Old Ales smell and taste of fruity esters, and when aged properly, can exhibit a rich and wine-like oxidation character. Typical examples are Founders Curmudgeon and Great Divide Hibernation Ale.
Thanks for reading! If you have anything to add or questions, feel free to use the comments below!