Lesson 7 - Sensory Analysis SAQ

**Detail the processes by which we detect the aroma, taste, and texture of beer and give an example of how each process can go wrong and so cause inaccuracy in sensory analysis.

Response:

Aroma:

The aroma of the beer is due to the volatile compounds in the liquid. The compounds evaporate from the beer and are breathed in through the nose directly or through the back of the mouth. The aroma molecules dissolve in the mucus of the olfactory epithelium where they bind to cells, setting off an electrical signal which is sent to the brain for processing. As the area of aroma detection is so small it is easily blocked. When you get a cold or an allergy which affect the nose, excess mucus is made; this blocks the route of the aroma molecules to the cells to which they need to bind in order to provide a signal to the brain. For this reason, people with allergies like hay fever are not suitable for the role of sensory assessor.

Taste:

The taste of beer is detected on the tongue, palate, and pharynx by cells which bind to flavour molecules and then send a signal to the brain. The cells are often clustered together to form taste buds. Some of the compounds in beer (like hop bittering compounds) tend to stick to the lining of the mouth, which means they continue to stimulate taste-sensing cells after the beer has been swallowed. This can lead to sensory fatigue which impairs the ability of sensory assessors to detect taste after a high number of samples or a sample with a particularly strong aftertaste.

Texture:

The texture, temperature, spiciness, and coolness are detected in the mouth and throat by stimulation of the trigeminal nerve. Signals from the nerve are then processed by the brain. The brain is not an infallible processor of information and aspects like mood, distractions, or conflicting stimuli can affect judgements made.