Whereas appearance accounts for the least number of points (3) when a beer is judged in a sanctioned AHA/BJCP competition, aroma provides the second most (12).  Much more than the appearance, the aroma gives a lot of information as to what you can expect in the flavor of the beer.  For me it also has been a difficult part of the evaluation process as I struggle at times to pinpoint exact components of the bouquet.  I suppose I just need to continue practicing!

Of course evaluating the aroma comes down to identifying characteristics of the malts, hops, and other aromatics (fermentation by-products, fruit, etc.) in the beer.  The struggles that I have is that it is somewhat the equivalent of doing a blind taste test.  You are looking at a glass of liquid trying to recognize things like currants or butter or coffee or molasses or vanilla.  It can be difficult to pick out certain aromas when you really don’t know what coriander or cloves smell like to begin with.  Even if you make yourself familiar with the smell of items like those listed above in their whole form, there will still be aromas and combinations that may stump you.

I think that the components of beer aroma generally break down to those from malts, esters, and hops.  Malts and grains often give off some sweet, roasted/toasted, caramel, or chocolate aromas (among others).  Esters from the yeast fermentation tend to provide fruit-like aromas such as apples, bananas, and berries.  Hops (for me) can be easier to pick out when they are out front and dominant, but much more difficult when they are subtle.  They can give off a wide range of fragrances from flowers to fruits to herbs to spices.  Certainly this is a lot of potential information to process, so you can see where it might be a struggle sometimes to pick out the more delicate parts of the overall bouquet.

It’s pretty important to take in the aroma of the beer shortly after pouring since it has been agitated during the pour and the aromatics have been released, becoming more noticeable at that point.  That may contribute to my struggles since I tend to be writing things down instead of getting to the aroma right away.  I also inhale the aroma multiple times even though it seems that if I don’t get it after the first few, I just don’t get it.  I have read that after about three or four sniffs of the beer, your sense of smell is pretty dulled.  So I guess the advice would be to inhale deeply on those first two.

I hesitate to refer to beer as having an odor when I do evaluations since that word is generally reserved for beers that may have defects.  That applies to homebrews much more so than what you and I will buy off the shelves, but we probably all know of a few beers that have had skunky (light-struck) aroma.

Though it is a part of the evaluation that may have some answers that are more correct than others, you still can only smell what you smell.  The important thing is that the aroma provides a preview (hopefully a good one) of the flavor and is not a step to be skipped.  For me it is definitely a good thing, since evaluating the aroma of a beer means that in moments I will be on to tasting!