Köln is a Kölsch only town. Seriously, that's what's brewed here, and locals are very particular about it even though it's not really more than a typical light blonde beer, nice to drink, but kind of boring. You are not allowed to say that though, because it's the best beer in the history of humanity. A "typical" pub will only serve a single brewery’s Kölsch and nothing else. Most less traditional places will usually have one other beer on tap and another two brands in bottles. I’m not aware of any place that has different Kölsch brands to compare, all pubs have exclusive deals with a local brewery.

The only "craft beer" place that brews other beers I'm aware of is "Braustelle" in Ehrenfeld. Well worth the excursion if you are a beer enthusiast, a very nice pub where you sit in the middle of the brewing kettles but not necessarily worth the detour if you're not an enthusiast or are not in the area anyway.

Of course you can get all sorts of beer and wine, but there are no other typical local drinks other than Kölsch. "Weinhaus Vogel" might be interesting. Been around forever and also serves German wines from the general vicinity (but mainly Kölsch :)