Smell is critical to tasting anything. Since the senses of taste and olfaction are linked, smelling the beer gives the palate a sense of what to expect. If you don’t believe it, try holding you nose as you eat something, and you will find your appreciation of the taste is significantly diminished. In fact our sense of smell is 10,000 times more sensitive than out tastebuds. Therefore, smelling the beer is arguably the most important step in a beer tasting.
Agitating helps to release the odours so the best way to sniff your beer is with a glass that is half empty. This allows you to give if a swirl with your hand over the top of the glass to keep in all the lovely aromas fighting to escape. Then stick your nose in and take a deep breath. The sense of smell is quickly saturated so make sure you concentrate and take particular note of the aromas you detect upon the first sniff.
The “dominant scent” is the initial aroma released during the pour, and (depending on the beer style) it can be a mixture of: malt, butterscotch, roasted barley, hops or other strong scents. You should also look out for any “off” odours such as the skunky odour of a light-struck beer, or the boiled caggabe smell of a beer suffering from a bacterial infection.
The more mellow “secondary scent” will come through as the beer settles in the glass. As you practice, you will learn to recognise and look out for floral, fruity and spicy scents. The final aromas that come through once the secondary scent fades, is the “residual scent”, sometimes referred to as the beer’s “signature smell”. This is whene the more unusual aromas, such as earthiness or nuttiness, are released which give a beer its unique character.