Take a look at the article written by Erin Meister for seriouseats.com. You should also check out some of her other articles, they are always well done and informative!
"It's time to delve a little deeper into the nuances of coffee's scent, and explore some of the main characteristics that professional tasters look for in a cup. You're ready for it, my coffee-tasting Jedi. Today we'll explore the three main categories of aromatic compounds found in roasted coffee, commonly referred to as enzymatic, sugar browning, and dry distillation.
When coffee cuppers approach samples for analysis, they are prepared to identify a host of different essences that the beans might have, including their sweetness, level of balance, and acidity, among others. Without some guidance, it can be difficult to pinpoint the specifics, but once you start to equate flavors in coffee with other things you taste all the time, unlocking the brew's mysteries becomes a bit more within reach.
Coffee is a complex food and is chock full of compounds that combine to create a different taste experience from one batch of beans to the next. One of the most important aspects of tasting, however, is smelling, and without knowing how to exercise your schnoz, the whole process might elude you."
Read the full article here! http://drinks.seriouseats.com/2012/04/coffee-cupping-aroma-what-coffee-smells-like.html
[Photograph: John McClumpha on Flickr]
Also read our article with more detailed explanation on how to describe coffee flavour, body, aroma, acidity and bitterness: