Sample Evaluation

Sensory testing is performed for three reasons:

  1. To determine the actual sensory differences between the samples
  2. To describe the flavor of the samples
  3. To determine the cupper’s preference for the samples

No single test can effectively address all of the above, but they do have common aspects. It is important for the evaluator to know the purpose of the test and how results will be used. The purpose of this cupping protocol is the determination of the cupper’s preference. The quality of specific flavor attributes is analyzed, and then drawing on the cupper’s previous experience, each flavor attribute is rated on a numeric scale. The scores between samples can then be compared. Coffees that receive higher scores should be noticeably better than coffees that receive lower scores.

The Robusta cupping form provides a systematic means of recording 10 important flavor attributes for Robusta coffee: Fragrance/Aroma, Flavor, Aftertaste, Salt/Acid Aspect Ratio, Bitter/Sweet Aspect Ratio, Mouthfeel, Balance, Uniform Cups, Clean Cups, and Overall. Defects, both Taints and Faults, may also be recorded on the form.

Quality Scale

Specific flavor attributes are positive scores of quality reflecting a judgment rating of the cupper; the defects are negative scores denoting unpleasant flavor sensations; the Overall score is based on the flavor experience of the individual cupper as a personal appraisal. These are rated on a 16-point scale representing levels of quality in quarter point increments between numeric values from 6 to 10.

These levels are:

Quality scale:         
6.00 – Good7.00 – Very Good8.00 – Fine9.00 – Outstanding
6.25   7.25     8.25    9.25
6.50   7.50     8.50    9.50
6.75   7.75     8.75    9.75

 

The above scale theoretically ranges from a minimum value of 0 to a maximum value of 10 points. The lower end of the scale (.25 to 5.75) is applicable to commercial coffees, which are cupped primarily for the assessment of defect types and intensities.

Individual Component Scores

On some positive attributes, there are two marked scales. The vertical (up and down) scales are used to rank the intensity of the listed sensory component and are marked for the evaluator’s record. The horizontal (left to right) scales are used to rate the panelist’s preference of the particular component based upon their perception of the sample and experiential understanding of quality. The attribute score is recorded in the appropriate box on the cupping form.

Each of these attributes is described more fully as follows:

Fragrance/Aroma: The aromatic aspects include Dry Fragrance (defined as the smell of the ground coffee when still dry) and Wet Aroma (the smell of the coffee when infused with hot water). One can evaluate this at three distinct steps in the cupping process: (1) sniffing the grounds placed into the cup before pouring water onto the coffee; (2) sniffing the aromas released while breaking the crust; and (3) sniffing the aromas released as the coffee steeps. Specific aromas can be noted under qualities and the intensity of the dry fragrance, break, and wet aroma aspects noted on the 6-point vertical scales. The score finally given is calculated by summing the vertical scales and should reflect the preference of all three aspects of a sample’s Fragrance/Aroma.

  • Enzymatic notes commonly found in Fine Robusta coffees include: Tea Rose, Lemon, Coffee Blossom, and Honey; while those commonly found in commercial (off-grade) Robusta coffees include Potato and Garden Peas.
  • Sugar Browning notes commonly found in Fine Robusta coffees include: Vanilla, Butter, Caramel, Cocoa and Walnuts; while those commonly found in off-grade Robusta coffees include Toasted Bread and Roasted Peanuts.
  • Dry Distillation notes commonly found in Fine Robusta coffees include Malt; while those commonly found in off-grade Robusta coffees include Pepper, Cedar, and Pipe Tobacco.
  • Aromatic Taints commonly found in Fine Robusta coffees include Coffee Pulp; while those commonly found in off-grade Robusta coffees include Earthy, Medicinal, Smoke, Rubber, and Straw.

Flavor: Flavor represents the coffee’s principal character, the mid-range elements, in between the first impressions given by the coffee’s first aroma and taste to its final aftertaste. It is a combined impression of all the gustatory (taste bud) sensations and retro nasal aromas that go from the mouth to nose. The score given for Flavor should account for the intensity, quality and complexity of its combined taste and aroma, experienced when the coffee is slurped into the mouth vigorously so as to involve the entire palate in the evaluation.

  • Flavor notes found in Fine Robusta coffees commonly include:
    • Fruit-like: cherry, black currant, raisin, raspberry, berry, dry fig, lemon, and prunes.
    • Nut-like: walnut, almond, and malt
    • Spice-like: clove, coriander and allspice
    • Sweet-like: molasses, syrupy, caramel, honey, dark chocolate, cocoa, and buttery
    • Overall: rounded, complex, complete, mellow, deep and delicate.
  • Flavor notes found in off-grade Robusta coffees commonly include:
    • Vegetable-like: grassy, hay, grain-like, barley-like, legume, potato, pea-like, silage, jackfruit, popcorn, and biscuit-like
    • Phenol-like: medicinal, metallic, rubbery, smoky, burnt, woody
    • Astringent-like: uric, salty, briny, brackish
    • Overall: dull, lifeless, flat, uneven, neutral, harsh, soapy

Aftertaste: Aftertaste is defined as the length of positive flavor (combined taste and aroma) qualities emanating from the back of the palate and remaining after the coffee is expectorated or swallowed. When an aftertaste is short or unpleasant, a lower score is appropriate. In Robusta coffees, aftertaste is often underscored by the potassium level found in the coffee, with high levels resulting in brackish (high saltiness and displeasing aromas) aftertastes and with low levels resulting in savory (low saltiness and pleasing aromas) aftertastes.

Salt/Acid Aspect Ratio: the Salt/Acid Aspect Ratio is responsible for the pleasing and delicate taste that is derived from distinguishable acidity and sweetness in Robusta coffees, stemming from the presence of fruit acids and sugars. It is also recognized because of lower levels of potassium and caffeine that make the Robusta coffee tastes coarse or harsh are absent from Fine Robusta coffees. This attribute is comparable to the strictly soft or strictly hard categorization of Brazilian coffees. The noticeable perception of acidity is one of the striking taste differences between Fine Robusta and off-grade Robusta coffees.

Bitter/Sweet Aspect Ratio: Both bitter and sweet taste sensations are present in Robusta coffees. The bitter component stems principally from the caffeine and potassium levels present in the coffee, while the sweet component is derived from the fruit acids, chlorogenic acid, and sugars levels in the coffee. Fine Robusta coffees have a low bitter and high sweet aspect in their taste, which Commercial Robusta coffees have a high bitter and low sweet aspect in their taste. In determining the Bitter/Sweet Aspect Ratio Score, the cupper rates the relative bitterness on a scale of 1 to 6, giving the higher score to the lower perceived bitterness, while at the same the cupper rates the relative sweetness on a scale of 1 to 6, giving the higher score to the higher perceived sweetness. The two scores are then added to determine the Bitter/Sweet score.

Mouthfeel: The quality of Mouthfeel is based upon the tactile feeling of the liquid in the mouth, especially as perceived between the tongue and roof of the mouth. Most samples with heavy Mouthfeel may also receive a high score in terms of quality due to the presence of brew colloids. Brew colloids are formed as the oils extracted from the ground coffee coagulate around the micro-fine bean fibers suspend in the brew. Mouthfeel has two distinct aspects: weight and texture.

Balance: How all the various aspects of Flavor, Aftertaste, Salt/Acid Aspect Ratio, Bitter/Sweet Aspect Ratio, and Mouthfeel of the sample work together and complement or contrast to each other is “Balance.” As the intensity of each of these attributes increases, it is more difficult for all the attributes to remain in balance. If each attribute increases equally in intensity, then the Balance score is high. If the sample is lacking in one or more attributes or if some attributes are overpowering, the Balance score would be reduced.

Uniform Cups: Uniform Cups refers to consistency of flavor of the different cups of the sample tasted. If a single sour, ferment, phenolic or other off-tasting bean is present in any of the cups, one or more of the cups will exhibit a different taste. This inconsistency in the flavor of the coffee is a very negative attribute. This type of inconsistency should be so distinct that the cupper can easily identify the off-cup in a triangulation with the other cups in the sample set. The rating of this attribute is calculated on a cup-by-cup basis. 2 points are awarded for each cup in the sample that is uniform (tastes like the other cups), with a maximum of 10 points if all 5 cups are the same.

Clean Cups: Clean Cups refers to a lack of interfering negative impressions from first ingestion to final aftertaste, a “transparency” of cup. In evaluating this attribute, notice the total flavor experience from the time of the initial ingestion to final swallowing or expectoration. If a single moldy, dirty, and baggy or other off-tasting bean is present in any of the cups, one or more of the cups will exhibit a non-coffee taste. Any non-coffee like tastes or aromas will disqualify an individual cup. 2 points are awarded for each cup in the sample that is free from a non-coffee like taste or aroma.

Overall: The “overall” score attribute is meant to reflect the holistically integrated rating of the sample as perceived by the individual cupper. A sample with many highly pleasant attributes, but not quite “measuring up” to the cupper’s expectation would receive a lower rating. A coffee that met expectations as to its character and reflected particular origin flavor qualities would receive a high score. An exemplary example of preferred characteristics not fully reflected in the individual score of the individual attributes might receive an even higher score. This is the step where the cuppers make their personal appraisal of the coffee. Good cuppers do not allow their personal preference for a coffee to interfere with the rating of the other flavor attributes of the sample.

Defects: Defects are negative or poor flavors that detract from the quality of the coffee. These are classified in 2 ways. A taint is an off-flavor that is noticeable, but not overwhelming, usually found in the aromatic aspects. A “taint” is given a “2” in intensity. A fault is an off-flavor, usually found in the taste aspects, that is either overwhelming or renders the sample unpalatable and is given an intensity rating of “4”. The defect must first be classified (as a taint or a fault), then described (“sour,” “rubbery,” “ferment,” “phenolic” for example) and the description written down. The number of cups in which the defect was found is then noted, and the intensity of the defect is recorded as either a 2 or 4. The defect score is multiplied by the number of cups in which it is found and subtracted from the total score in calculating the Final Score, following to directions on the cupping form.

Final Scoring

The Final Score is calculated by first summing the individual scores given for each of the primary attributes in the box marked “Total Score.” Defects are then subtracted from the “Total Score” to arrive at a “Final Score.” The following Scoring Key has proven to be a meaningful way to describe the range of coffee quality for the Final Score, with scores above 80 equating to Fine Robusta coffees.

 

Total ScoreQuality DescriptionClassification
90-100OutstandingVery Fine
80-90FineFine
70-80Very GoodPremium
60-70AverageUsual Good Quality
50-60FairUsual Good Quality
40-50FairCommercial
< 40Exchange Grade
< 30Below Grade
< 20Off Grade
< 10Triage