One of the many great things about Rotterdam is that it is so close to Belgium. More importantly all those lovely monks and others who spend their time brewing beer. There are anumber of bars who specialise in selling this lovely stuff. I really like the Boudewijn Belgian Beer Cafe on Niewe Binnenweg. It’s perfect for an afternoon beer and croque monsieur in the early October sunshine.
Bokaal across the road from my apartment is also excellent though the beer selection is a bit smaller. I’ve written previously about enjoying a Witkap Dubbel here
Thirdly if you’re really into choice in a big way, try Locus Publicus at Oostplien. Despite its corny name it’s cosy, atmospheric and busy. The choice is vast. My advice us to start at the top. You won’t get that far. Most of the beers are 6 or 7% with some in the early 20s. I think I now know why Google maps told us to beware of Belgium.