Originally Posted by
TheMadBrewer
Früh wins on location but Malzmühle and Päffgen win on bier (i.e. Kölsch). But then again, the OP said they weren't a drinker.
But Köln will never be the same now that Lommerzheim ("Lommi's") is gone
My all-time favourite for Koelsch would be the
Backes (serving Reissdorf Koelsch) in the southern part of central Cologne. Got very good memories from there and for me it represents everything I love about Cologne: Arts and artists, no social division, great
Frikadellen 
and an unhurried but steady supply of the great Cologne beer.
Lommi I had the chance to visit a few times. Amazing place that is preserved in a dedicated pictorial book.