The Brilliant Beer Co.
-Science of Taste-
When it comes to drinking the beer the first stimulus is the smell (odour or aroma).
We can detect the smell of food and beer in two different ways, but largely using the same sense (smell) receptors.
Smell detection through the nose Taste receptors on the tongue
And via the nasal cavity (retronasal and back of the throat.
Cavity).
To explain the difference we will use two terms to describe smell:
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The Odour of the beer is the smell detected by smelling the beer directly from the glass. The volatile compounds enter the nose via the nasal passage. The odour will be greatly effected by the temperature and the head on the beer which influences the ease with which volatile compounds can escape from the liquid.
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The aroma of the beer comes after the beer has been taken into the mouth. The volatile compounds pass up to the nose through the retronasal passage. The aroma of a beer is often stronger than the odour since the beer is warmed in the mouth and is not effected by the presence of foam.
When tasting un-carbonated drinks the volatile compounds are released due to an increase in temperature. With carbonated drinks (such as beer) this release of aroma compounds is increased through the breakout of CO2 on the rough surfaces in the mouth increasing the rate of flow of volatile compound in the vapours going to the retronasal passage. The release of volatile compounds is enhanced in the presence of alcohol, which has a lower boiling point than water, and hence vaporises more easily, and being a polar molecule more readily carries the more flavour active compounds.
When the beer enters the mouth it also comes into contact with the taste buds located in the mouth. The taste receptors are located on the tongue and at the side of the mouth, and are limited to four basic tastes:
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Sweet
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Sour
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Salty
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Bitter
There are also other sensations which can be detected in the mouth and these include texture, sometimes called “Umami”, and pain which can be stimulated by extreme temperatures or high levels of carbonation.
Lastly having tasted and smelt the beer there are residual sensations which remain in the mouth called mouthfeel, these represent the texture of the beer, and certain tastes and sensations may linger in the mouth and top of the throat after the beer has been swallowed; these are described as after-taste or hang.
In deciding if a consumer likes the “taste” of a beer he goes through a series of complex and often subjective evaluations, and since each individual is unique these will be different for each consumer. Not only will there be variations between tasters, but depending on health (e.g. a cold) or mood the same tasters may give different results on different occasions.
Such subjective assessments could not be used as a basis of a Quality Control procedure, and hence specific tasting procedures have been developed.