I'm visiting Hamburg September 14-18. I may (or may not) have time to myself in the evenings, I will probably have some time to myself on the weekend. Anything I can't miss? I think I see there's some kind of Hamburg beer week going on.
I've been to Hamburg only once, and with the exception of a few pilseners and weissbiers at the hotel bar, I only had time to stock up on beers to take home, in the beer store BierSpezi Hoheluft, in Hoheluftchaussee 117. But there are now other good beer stores too, and of course plenty of beer bars, and some brewpubs. If you have time, I'd definitely check out what's on in the Hamburg Beer Week.
I've heard there's a street called The Reeperbahn in Hamburg. But since I've never been to Hamburg, I can't comment on it. Google will tell you all about it.
My only suggestion on beer in Hamburg is keeping an eye out for HAAKE BECK KRÄUSEN which is an unfiltered pilsner. To my knowledge it's a draft only offering so you'll have to look for bars/restaurants that serve the Haake Beck brands indicated usually by outdoor restaurant signage.
You should check out Bar Oorlam. Super cool bar that's the taproom for local craft brewery Buddelship. They brew a bunch of North European beers, super tasty, great ambience, and they have some outdoor space that you should still be able to enjoy in September. Went with my dad last year, we liked it so much we went back a second time.
Rerate, on tap at Cardinal Pub & Bar, Stavanger. Also available there bottled. ABV is 4.8%. Very pale golden colour, large white head. Aroma of herbal and grassy German hops, also fruity notes, a hint of honey. The flavour is crisp and not too sweet, decent herbal German hops throughout, fairly bitter finish. A typical North German pilsener, very refreshing. Flensburger Dunkel and Weizen, and other Flensburger beers, are also worth sampling. Don't know how readily available they are in Hamburg, though.
Duckstein beers (top fermented / obergäriges) should be available in Hamburg. They used to be brewed by Holsten, but now they are brewed in Lübz.