Coffee characteristics

Maybe someone can help me. I had attended a coffee cupping some 6 months ago, what an eye opening experience. One of the charcteristics that came through with one of the cuppings was the smell / scent of fermenting grain. I have brewed beer in the past and it reminded me of the smell created in the fermentor, when the yeast is consuming the available sugars and converting them to alcohol. Is anyone familiar with where that smell might come from in coffee? Is it simply a product of the process or is it impacted by the variety and roast level as well? The particular coffee I sampled during the cupping was a Kenya AA natural process. It was truely a unique cup. I have had other Kenya AA's but it is not quite the same (some not even close). If anyone has thoughts on this subject, I would like to start a discusion covering this subject.