A SENSORY EVALUATION OF COFFEE

The physical actions used in a sensory analysis of coffee, such as smelling sipping and swallowing are the same actions we normally perform when eating and drinking. By exaggerating such actions, we stimulate the maximum number of nerve terminals to allow a more complete sensation of the taste. The testing cycle consists of 6 stages.

• Fragrance

First, identify the fragrance. The easiest way to do is: take a certain amount (around 10 grams) of ground coffee in a cup or hold it on your palm. Then, smell the coffee energetically to perceive the gases from the aromatic compounds which carbon dioxide releases when cells break under the grinding process. The characteristics of the fragrance will hint at the taste you will have: a sweetish fragrance indicates an acid taste, while a pungent or acid fragrance produces pungent and strong tastes.

• Aroma

Second, check the aroma from the infusion. The easiest way to do this is: Pour boiling water onto freshly ground coffee which is then left to soak for 2-3 minutes, till a kind of crust forms to cover the whole water surface in the cup. Stir the liquid with a spoon and take a long deep breath through the nose to inhale the maximum amount of gases given off by the high temperature water. This action gives an idea of the aromatic personality of the sample, which can vary from fruity to grassy, from earthy to chocolatey, to spicy etc.

• Taste

To evaluate the taste, sip deeply the liquid prepare in phase 2, forcing it through the front incisor teeth.  This action oxygenates the liquid and spreads it on the palate and over the entire surface of the tongue, for all the sensory nerve terminals to simultaneously react to the sensation of sweetness, saltiness, sourness and bitterness, to obtain a full modulation of taste. For a more homogeneous evaluation, keep the liquid in your mouth and rotate if for 2-3 seconds. This lowers the temperature and better saturates taste receptors. Thus, secondary taste can be perceived alongside with the basic ones.

The basic tastes perceived through the tongue are as follows:

Sweet  which is detected by the tip of the tongue

Bitter   which is detected at the base of the tongue

Acid     which is detected by the tip and at the back sides of the tongue

Salt      which is detected by the tip of the tongue

• The Olfactory sense

Analyze coffee simultaneously for both taste and smell. Spreading the liquid over the surface of the tongue produces an aeration leading to the gasification of a number of organic components present in the liquid. Sip the infusion with energy and these gases will pass onto nasal cavity. The simultaneous evaluation of taste (the liquid) and smell (the vapours) will reveal the special flavor of the coffee sample you are analyzing.

• The Aftertaste

The aftertaste is the sensation that remains on the palate after the drink has been swallowed. To this end, swallow only a very small quantity of liquid after keeping in your mouth for a few seconds. Some components of the flavours left as an aftertaste can remind of tastes like chocolate (sweet), wood or tobacco smoke (scorched), spices (cloves) or pine snap (resinous). These characteristic tastes may even be combined.

*In general, swallowing a quantity of the infusion is not advisable, particularly of you are taking part in a busy and tasting session. Keeping the liquid in your mouth before spitting it out is well enough to identify the tastes and to send vapours to the nasal activity.

• Body

To conclude coffee tasting, evaluate the body of the infusion. Pass you tongue delicately on the vault of your palate to derive a tactile sensation.  The oiliness or slipperiness levels measure the fat contents of the infusion. The greasiness or viscosity levels determine the fibre or protein content of the infusion.  Oiliness and viscosity together define the body of coffee.