How much damage do aphids cause to hops?

I have been growing hops by luck. Last year I gave them a 3 pole teepee to climb and they flourished and were beautiful. This year they were looking gorgeous once again, but days before I was about to pick them they became infested with aphids. The explosion and destruction has been shocking. My beautiful green cones are crawling with them and are suddenly turning brown (a separate problem?). Some cones even have grey-black mold-looking stains I their bottom leaves. HOWEVER, they still smell great and still have ample golden magic. Question: are my hops history or are they still worth picking. My home brewing neighbor who has been a defender and supporter of my hops now turns up his nose. How badly will the aphids effect my hops and our beer?