Last Updated on November 4, 2022
Although humans have been drinking coffee for centuries, before the late 19th century coffee was bought and sold by appearance alone. However, appearance does not always predict coffee quality. Cup taste testing, or “coffee cupping,” began in the 1890s on the west coast, to grade coffee quality and reveal imperfections that are not identifiable by the visual attributes of the beans.
What is Q grading?
Q grading is the process of evaluating coffee quality. Today’s Q grading system was launched in 2004 by the Specialty Coffee Association (SCA) with the intention of standardizing how the coffee industry defines specialty coffee (see last month’s article).
A certified Q grader is like a coffee sommelier. They are somebody who has been licensed by the Coffee Quality Institute to evaluate coffees using the SCA guidelines.
Q grader certification requires a person to complete a six-day training course in which they are exposed to a wide array of coffees of different origins and attributes. They learn how to evaluate coffee by aligning to the SCA best practices and vocabulary for describing the quality of coffees. There are no prerequisites, but participants are typically already experienced at evaluating coffee quality using the SCA cupping form. The course covers the cupping skills and grading protocols, and the grader exam assesses an individual’s ability to consistently cup and grade green Arabica coffee beans.
Components of the Q score
The Q grade that coffees receive is a total score comprised of 10 individual components: Fragrance/Aroma, Flavor, Aftertaste, Acidity, Body, Uniformity, Balance, Clean Cup, Sweetness, and Overall. Each of these individual components receives a score out of 10:
These components are summed together for a total Q score. An Arabica coffee that receives a score of at least 60 is considered commercial grade coffee, and one that receives a score of at least 80 is considered specialty coffee.
Fragrance/Aroma: Fragrance is defined as the smell of the dry ground coffee, and aroma is defined as the smell of the ground coffee when infused with hot water. There is also a spot to write in specific qualities, or attributes, which is where the Coffee Taster’s Flavor Wheel may be useful.
Flavor: This component encompasses both the gustatory (taste) and retronasal aroma (flavor-by-mouth) aspects of the coffee. Retronasal aroma is the perception of odors that travel from the mouth and up the nasal passage. The flavor score accounts for intensity, quality, and complexity of the combined taste and aroma.
Aftertaste: Aftertaste is the length of positive flavor (taste and aroma) qualities that remain after the coffee is swallowed or spat out.
Acidity: In cupping, acidity is typically described as “brightness” when favorable and “sour” when unfavorable.
Body: The body quality is the tactile sensation of the liquid in the mouth. A coffee with a thick mouthfeel is considered full-bodied, whereas the opposite is light-bodied.
Uniformity: This refers to how consistent the flavor is throughout the different cups tasted. Coffee that is highly variable in flavor would receive a low score for uniformity.
Balance: Balance represents how all the other aspects of flavor, acidity, body, sweetness, etc. complement or contrast one another. If certain attributes of the coffee are overpowering while others are lacking, the coffee would receive a low score for balance.
Clean Cup: This component refers to the total flavor experience and the extent to which there are interfering negative impressions throughout tasting.
Sweetness: Sweetness is one of the fundamental tastes, but in SCA cupping, it also refers to a pleasing fullness of flavor, and the opposite of sour, astringency or “green” flavors.
Overall: This component is a holistic, integrated rating of the sample overall.
Impact of defects on the Q score
In addition to receiving a Q score of at least 80 to be considered specialty coffee, an Arabica coffee must also have minimal defects. As specified in the SCA Grading Green Coffee protocol, it must have no primary (Category 1) defects and no more than five secondary (Category 2) defects.
Defects are negative scores subtracted from the total Q score, denoting unpleasant flavor sensations. They are described in more detail in the SCA Defect Handbook. Defects can make a score less than 60, which would make it unsuitable for commercial grade, or less than 80, making it unsuitable for specialty grade.
An off-flavor defect in green coffee is classified either as a taint or a fault. A taint is given a defect score of 2 in Q grading, and it indicates a noticeable, but not overwhelming, off-flavor. Taints are often found in the aromatic aspects of the coffee. A fault is given a defect score of 4, indicating a noticeable and overwhelming off-flavor that essentially renders the coffee unpalatable. Faults are often found in the taste or flavor-by-mouth aspects of the coffee.
The defect scores are subtracted from the total score, resulting in a final Q score.
The future of Q grading and the Fourth Wave
The current Q grading protocol is sometimes criticized for being too subjective.
First, coffee quality is determined by just a small number of people, coffee experts, without considering preferences of the target consumer population. Desirable coffee flavor is not the same for every taster.
Second, the Q score itself is somewhat subjective. It is comprised of 10 components that are given equal weight and summed into one total score, without considering or measuring the intensity of the key sensory attributes of the coffee. Even the individual components themselves are biased, with some of them combining both subjective elements (pleasantness) and objective elements (intensity) into one unweighted sub-score.
Coffee research has increased in the last decade, and with that, coffee professionals are pushing to develop improved protocols to make the Q grading process more scientific. There has also been a push to develop a Q grader certification program for producers and small roasters, to improve Q grading capabilities globally.
With the coffee community striving to understand coffee science better, some people think a fourth wave of coffee is coming (see my last article for an explanation of waves)—one that embraces coffee’s scientific aspects, from agricultural practices, to brewing and roasting, to sensory attributes and preferences.
Specialty Coffee Association, Protocols & Best Practices: https://sca.coffee/research/protocols-best-practices