I have been smelling sour smell for 4 weeks now and as a 2nd year BK am worried it is AFB. I'm in a close, residential spot, so I smell the hive daily. Goldenrod has been in bloom for 4-6 weeks (IL), so maybe the hive is o.k. and this smell is "normal". (the attached comments were from another thread, but it makes me hopeful.)
If you have AFB you should smell something on the order of dirty, sour, wet, socks along with your visual inspection.
No, if you smell that you are just smelling the bees ripening goldenrod nectar. AFB smells like rotting meat.