The old brewery at 1042 Dean Street remains a constant point of fascination for me. Googling hasn't turned up any old photos of the brewery during its heyday, so I think I'll have to head for the public library, but it must have been quite an operation, given the size of the place. I also want to write an open letter to Matt Roff (of Franklin Park and Southpaw) begging him or someone of his ilk to turn the original buildings (above, with the grey siding) into a big cozy brewpub. You could use the grungy single-story brick building to the right for storage or a music space, and the big old tank on top could serve as an awesome landmark sign. I'm sure that's just the venture people are looking for in this market.
I found a few good histories of Brooklyn Brewing online, including this one from the Brooklyn Historical Society and this review of their exhibit, the latter of which cites both German immigration to Brooklyn and the quality of Long Island water as factors in the brewing boom in 19th century Brooklyn (12 blocks of Bushwick once sported 58 breweries!). This is particularly interesting given that a lot of sources cite the lack of access to decent drinking water as a major reason that Brooklyn voted for the consolidation of 1898. Consolidation, and access to New York's upstate water sources, led to the filling-in of the reservoir that once sat atop Mt. Prospect above the Brooklyn library (visible on this historical map of Prospect Park).
A number of factors killed brewing in Brooklyn, chief among them prohibition, but this opened the door for another boom: Brooklyn candy. Cited as a substitute good for beer by contemporary sources, and also something a brewery could be refitted to produce, candy production was big in Brooklyn in the first half of the 20th century. The Domino Sugar refinery in Williamsburg (keeping its iconic sign as it transitions to condos) was a plus, too.