Describing the experience of flavor is difficult since it is experienced only by the individual (different people perceive the same stimulus in different ways) and can be affected by outside iinfluences, such as one's own mood and expectations. In making an honest evaluation of one's own roasting efforts, it is useful to have a good vocabulary to describe one's taste experiences.
Usually, one decides if the food/beverage is liked or disliked by developing an overall impression. Professional tasters find it useful to also consider the details of the flavor experience, the factors that are causing one to percieve a food or beveage in a certain way. With coffee, this is more difficult than it sounds because coffee is a complex beverage that has literally thousands of flavor active chemicals (Flament, 2002) that combine, contrast with, and are disguised by each other. The perception of brewed coffee changes over time due to change in temperature, loss of aromatics, and evolution of flavor. One must consider how the coffee tastes at all temperatures to get a full impression of the quality of the sample.
Though this sounds complicated (and most professional coffee tasters spend years developing their sensitivity and vocabulary), it is possible for the roaster to objectively perform a detailed evaluation of their coffees and learn a lot by doing so. The following are suggested parameters for doing this successfully:
- Design a formal step-by-step evaluation where the parameters of coffee preparation and tasting are consistent. While one may not need to go through a formal cupping, consistent flavor preparation will ensure that one is making a more direct comparison based on the coffee's quality, rather than some extraneous occurrence. The same quality of water, grinding, method of brewing, etc. should be consistently used.
- A regular procedure should be used, with coffees tasted at certain times. It is often recommended that the coffee be tasted at three temperatures: fairly hot (but not so hot as to burn one's mouth), slightly cooled, and barely tepid. This will allow one to get a full impression of the sample.
- The test should be performed in a comfortable, quiet, and well-lighted place. If others are participating, the initial part of the test should be performed in silence so that all can develop their own independent impressions. Even facial expressions from another person can influence one's own perception for better or worse.
- The main discipline is to pay attention to the details of one's experience from beginning all the way through to the last vestige of the aftertaste and then to record one's impressions. One has to allow the experience to happen as far as possible free of pre-conceptions or hopes and fears about how the coffee will taste. On the other hand, one cannot get to serious about it; heavy-handed overconcentration can create impressions where none really exist.
Flavor qualities of anything are discussed in terms of how they are experienced by different sensory systems of the body and most flavor vocabulary comes from that viewpoint. The basics are:
- Aromatics, perceived by the olfactory lobe at the top of the nasal passages.
- Tastes, perceived in the mouth.
- Tactile sensations, the physical sensations of texture, temperature, and feel of the liquid.
- Irritating (trigeminal) sensations, such as pungent aromas or chemically-induced sensations of hot (chili) or cold (menthol)
Aromatics are the most varied sensations and a major part of the enjoyment of coffee; many people who do not drink coffee still enjoy the aroma. They are also fleeting and can happen quickly. Due to their diversity, they are usually classified into categories using different systems. One developed by the International Coffee Organization (ICO) is given in the following table (Wintgens, 2004, p. 814).
|Fruity/citrus||Caramel, malty, toast-like||Earthy||Grassy/green/herbal||Animal-like||Burnt/smoky|
Coffee aromatics are traditionally evaluated in two ways: when the coffee is dry and freshly ground (referred to as the "fragrance") and when it has been infused with water or as present in the liquid.
A slight confusion exists in the use of the terms "taste" and "flavor". Often, they are used interchangeably, but in this case we use the more formal definition of taste as " the special sense that perceives and distinguishes the sweet, sour, bitter, or salty quality of a dissolved substance and is mediated by taste buds on the tongue" (http://www.merriam-webster.com/dictionary/taste, retrieved July 30, 2009). These are the sweet, sour, salt, and bitter tastes.
Sour often connotes an unfavorable experience, but many favorite foods and beverages have pleasant levels of sourness (lemonade, wine). As in other beverage analysis systems, a pleasant sourness is referred to as "acidity". Coffee has a number of types of acids that give both favorable and unfavorable experiences. Fruit acids present are the same chemical compounds found in fruits, such as citric acid, malic acid (found in apples), and tartaric acid (found in grapes). There are also aromatic (volatile) acids, so-called because they can be smelled as well as tasted (acetic acid, or vinegar, and lactic acid, found in yogurt, sour cream, and buttermilk, are typical). There are many others, such as quinic acid which is somewhat bitter as well as sour (think of tonic water). These all combine to create a coffee's acidity. As seen on the roast flavor development page, these are most prominent at lighter roasts.
Coffee is not a sweet beverage in the sense of a soft drink (which has added sucrose), but small amounts of sweetness have a positive effect on the overall impression of the coffee. The sucrose present in a green coffee is mostly sublimated into carmelization and formation of aromatics. Remaining sucrose (with other carbohydrates) are responsible for enhancing other tastes (acidity without sweetness is just sour; same for bitterness).
The salt component is not the same sodium salt that is most familiar, but a combination of other metal salts, especially potassium. A certain level of this saltiness can add balance, but if too much is present (or without adequate acidity and/or sweetness) the coffee can taste "rough". Unlike, the other tastes, salts are stable at roasting temperatures and do not change as the result of roasting, but the perception of levels of salt will change in concert with other tastes.
Bitterness is a commonly heard complaint about coffee, though some people often use the term incorrectly, confusing it with astringency (discussed in the section on tactile sensations) or sourness. There are a number of sources of bitterness in the coffee beverage. The green bean has chlorogenic acid, which is usually perceived as bitter/green, and is sublimated during roasting into quinic and other more sour/bitter acids. Other chemicals produce a bitter response (trigonelline, for instance) and are also sublimated during the roast into other aromatic and taste components. This sublimation is one reason why allowing enough time in roasting can contribute to better flavor.
The most well known tactile sensation in coffee is body defined as a heaviness (Flament, 2004, p.813) of the liquid in the mouth. It is the result of a combination of aspects including the dissolving of the coffee cell wall, presence of oils, and presence of sweetness (very sweet coffees are often described as "syrupy" or "round"). Also to be considered is astringency, the drying of the mouth. All coffee has some astringency, but it should not be over-powering. Coffees with a large number of immature beans or black beans usually taste much more astringent.
There are a seemingly infinite number of ways that these flavor attributes can combine or contrast to one another. One of the main ways this happens is in perception of flavor, the combination of aromatics and tastes. An example would be the flavor of an orange, essentially a combination of citric and other acids, sweetness, and "orange" aromatics. Since we have a learned experience of this, we recognize this flavor and may even subconciously "fill in the blanks" if enough of the flavor attributes reminiscent are present. Some combinations are expected and when appearing together will be percieved more definitely (caramel aromas and sweet, fruit aromas and acid, vegetal aromas and bitter). It is this overall impression that most consumers relate to in appreciating (or not) a coffee.
Reading the Radar Chart
Since there is a lot going on in any food, one way of developing an image of the overall effect is by creating a radar chart of the flavor attributes found in a sample. These charts can be as detailed as one chooses to make them and they are easily created in spreadsheet programs such as Excel. Flavor attributes are listed in the order they are perceived starting at the top and going clockwise. The attributes themselves are listed on the spokes of the wheel and the intensity of the attribute is illustrated by the distance from the center (the greater the distance, the stronger the attribute). On this site, it is used to illustrate the changes in flavor attributes as the roast progresses. An example of the chart is seen below.
LightToMediumRoastFor more information and a more detailed way of looking at coffee flavor, check out the coffee flavor wheel at Sweet Maria's website.