I have only twice visited Berlin, in 1970 and 1987, both times before the wall came down. I intend to get back hopefully in the next couple of years. As far as beer is concerned, Berlin does not enjoy the reputation Munich has, but I still maintain that while Munich is a great place to drink beer with its beer halls and beer gardens, you can find beer just as good outside of Munich or even Bavaria. Just my opinion.
As for Berlin, there are two traditional brands associated with the city, Berliner Kindl and Schultheiss, which I understand are now under the Radeberger company-the once dominant beer of East Germany (DDR). I have sampled all three, in Berlin (West and East and in Dresden (Radeberger). I have no particular memories of any of them being standout, but hopefully, I can refresh that memory soon.
Berliner Kindl has one of the best logos in Germany with a blond-hair boy's head sticking out of a mug.
My last time in Berlin I found a great metal Berliner Kindl poster in a shop and still have it.
In addition, to the above two brands, Berlin is famous for the Berliner Weisse which is a drink consisting of beer with some kind of raspberry syrup added. It is light and refreshing, but doesn't replace a pils or lager.
One of my favorite photos of old Berlin (before it was bombed) is that of Potsdamer Platz, which used to be the site of a large restaurant owned by Munich's Pschorrbrau.
Potsdamerplatz-The Pschorrbrau restaurant is on the right side.
Berlin apparently is better for beer gardens that for actual beer halls, which is more to Bavarian culture. The Munich brewery Weihenstephaner does have such an establishment in Berlin, however.
Now-a-days the word is that Berlin is filled with micro brews, restaurants that produce their own. Here is a posting that describes the recent beer scene in Berlin (Hat tip Ron Pattison).
Berlin's beer fest comes in August. I have never attended it. but it is apparently huge featuring beers from other countries as well. It only last three days, however.
Berlin is a fabulous city with much to see. With its fabulous nightlife, finding good beer should not be a problem.