The three major parts of coffee evaluation include fragrance, aroma and flavour.
Fragrance (dry ground coffee)
This is the first and often most intriguing and complex part of the sensory evaluation. The fragrance is the perception of volatile compounds that escape the ground coffee. These volatile compounds are the least stable (weak inter-molecular bonding) and this is why they leave the ground coffee and enter the environment. With lots of practice and focus it is possible to pick up particular fragrances from the ground coffee, which enables us to give a description of the smell (eg. apple, citrus, chocolate, caramel etc). The way in which a coffee is grown and processed, as well as the particular variety of coffee used, has a dramatic effect on its fragrance. For example, naturally processed coffees often have a fragrance of fruit, berries and chocolate, whereas the same coffee processed using the washed method may smell of caramel, citrus, flowers and honey.
These fragrances are not tasted in the cup. As the smells are made of volatile compounds, it is not possible to keep them in the cup of coffee. As soon as the fragrance leaves the coffee, it becomes less complex and vibrant. This is why we grind fresh for every cup of coffee we make!
Aroma (wet/brewing coffee)
This is the smell of brewing coffee. The aromas of brewing coffee likely include caramel, nuts, chocolate, citrus, honey and brown sugar. When hot water comes into contact with ground coffee, the coffee absorbs the water until it is saturated. Once saturation has occurred, the flavour and aroma within the coffee grounds can be released. The change of state of water from liquid to vapour (steam) also helps some volatile compounds to escape the ground coffee and enter the air. The aromatics released are slightly different to the dry ground coffee fragrance as these particular aromatics are slightly less volatile (they needed hot water to allow them to be released). This is shown by the fact that cold coffee has significantly less aroma than hot coffee and cold-brewed and cold-drip coffee have almost no aromatic element.
These aromas are not always picked up in the tasting part of the process. In fact, the majority of flavours are perceived through the olfactory sense (smell). This is one of the major reasons why a coffee enjoyed in a ceramic or glass vessel will taste better than a coffee in a paper cup with a lid. This is also why your taste is affected when you have a blocked nose. This can be proven by holding your nose and drinking a coffee, then try it without holding your nose. The difference is remarkable.
Flavour (taste, texture, balance)
This is the actual tasting of the brewed coffee. Coffee is slurped into the mouth from a deep-bowled spoon. This is to aerate and spread the coffee throughout the palette. The aim of this part of the evaluation is to determine things like texture, acidity, sweetness, saltiness, bitterness, richness, balance and of course any specific flavours that are recognised. The combination of all three of these categories constructs a flavour profile of a coffee.