Tastes and aromas are subjective things and everyone perceives them slightly differently. Furthermore a person's sensitivity of taste depends on what food or drink they have consumed recently, how well they are feeling and how old they are amongst others things. A persons sense of smell can vary considerable too as well as being a function of age and general well-being.

However professionals in the coffee industry still need some type of criteria when discussing and analyzing coffee samples and so they have attempted to create a common language amongst themselves to help them compare and understand certain characteristics of coffee taste and aroma.

Whether these professionals are testing for consistency of product or are sampling new blends they have created four basic descriptive criteria that are recognised amongst themselves.

1. Acidity - This is the most important distinguishing characteristic of coffee. It is defined as a pleasant sharpness around the edges of the tongue and towards the back of the palate. The sensation may be described as dryness by some people. Acidity should not be confused with sourness, as a good coffee should have some degree of acidity.

Acidity provides the punch to a coffee and a lack of such will result in a dull, flat lifeless brew. Coffees described as mellow have low acidity, but should have enough to avoid blandness.

2. Body - This refers to the texture of the coffee as it is perceived in the mouth. Is it rich and heavy or light and watery for example. The body or texture of a coffee is in direct proportion to the amount of oils and soluble compounds extracted during the brewing process. A stronger brew for example would be considered to have more body.

3. Aroma - This refers to the sensation perceived by the nasal passages as a result of interaction with the aromatic oils and volatile compounds released during the brewing process. To properly appreciate the aroma, the nose should be within a couple of inches of the brew and several deep breaths taken through the nose. Descriptive associations are then used to describe the smell. Examples include, burnt, fragrant, musty, nutty, winey, spicy, chocolaty, earthy and bland.

4. Flavour - This is used to describe the overall effect of the previously discussed acidity, body and aroma plus the main sensations experienced by our tongues such as bitterness, sourness, saltiness or sweetness. This is the most difficult criteria to get right and can be very subjective. However a professional coffee taster will comment on the complexity of the flavour, the balance (if no one characteristic dominates) and the depth of body.

In addition to the terms used for relating to the aroma, a professional will use other terms such as bright, buttery, caramelly, fruity, grassy, harsh, lifeless, mellow, muddy, mild, rubbery, and wild amongst others when describing the flavour.

Clearly describing and distinguishing between coffees can be complex but with these guidelines and some practice you should now be able to give it a go.