Running Boston Marathon tomorrow. Staying at the Intercontinental on Atlantic Ave, will probably just walk there from finish line, looking for a good place in between to pick-up some quality brew to bring back to the hotel. Cheers!
Two spots I can recommend are: Bacco's Fine Foods on 31 St James Ave, in the same building as fire + ice. This is maybe two blocks from the finish line. Typically have a small but solid selection including JA, Victory, MBC, Stone, GI, etc. The one knock is that most are unrefrigerated. They also have a great selection of meats and cheese that might hit the spot. In a separate store front they have a small grocery store with sandwiches, premade meals etc. BWX: Closer to your hotel on 181 Devonshire, so it may make more sense for you. Huge selection and you'll find the occasional gem. They have pretty much every MA brewer you can think, a nice sour/Belgian section, and a ton in coolers too. Spotted 40s of Lagunitas sucks there the other day.
