The flavor is a term that encompasses all of the other cupping parameters. It is an overall evaluation of the coffee and is often measured against a standard chart or ‘flavor wheel’.
Acidity is the bright and dry taste that gives a cup its life. Perceived acidity does not necessarily correlate to the pH of a coffee, but is believed to be the result of the acids present in coffee. Acidity is akin to the dry but bright sensation experienced on the sides at the back of your tongue when drinking red wine.
Kenyan coffees are very acidic, as are many wet-processed coffees. Dry, processed coffees have a low-toned and subtle acidity. It is important to note that as the roast develops, acidity decreases. High amounts of acidity are not desirable in espresso coffee.
Even instant coffee has some of the 800 compounds responsible for stimulation of our taste buds. The difference, however, is that instant coffee lacks most of the aromatic volatile compounds causing a dramatic decrease in the overall flavor. The perceived acidity of coffee results from the proton donation of acids to receptors on the human tongue. Acidity is typically a highly valued quality especially in Central American and some East African coffees.
Sourness, however, is an extreme of acidity, and can be considered a defect.
Acidity has been correlated with coffees grown at very high altitudes and in mineral rich volcanic soils. The perceived acidity of washed coffees is also significantly higher than the acidity found in naturally (dry) processed coffees.
This is likely to be due to an increase in the body of naturally processed coffees relative to wet processed coffees since body masks a coffee's acidity. The acid content in a brew is also greatly dependent upon the roast degree, type of roaster, and brewing method. Cuppers use a scale from 0-9 to assess acidity – coffees with scores of 6-7 are highly acidic.
Aftertaste is the sensation that is experienced after the coffee is swallowed. Cuppers assess the permanence of the aftertaste, i.e. how long it takes from the initial aromatic sensation on the back of the throat to the loss of this sensation.
The body is the weight of the coffee that can best be sensed by allowing the coffee to rest on the tongue and by rubbing the tongue against the roof of the mouth. Body ranges from thin, to light, to heavy and is a result of the fat content of the coffee. Medium and dark roast styles will have a heavier body than lighter roasted coffees, but conversely will have less acidity.
The coffee’s aroma is due to a complex mixture of volatile compounds in the brew. Nearly 800 compounds have been identified as affecting aroma, including sulfur compounds.
Coffee’s bitterness, sourness and astringency are all affected by roasting procedures and various levels of hydrocolloids, caffeine and a range of acids. At low levels, bitterness helps mask the acidity and adds another favorable dimension to the brew. However, at high levels, bitter compounds can overpower the other components present in coffee producing an undesirable effect.
Decaffeination slightly reduces the perceived bitterness of coffee. Allowing the coffee to soak in fresh water for approximately twenty-four hours after the fermentation process - as practiced in Kenya - is said to reduce bitterness. A coarser grind reduces bitterness. However, the correct grind size should always be used to ensure proper extraction.