Course Overview & Purpose• Knowledge base for evaluation 

and grading of Arabica green coffees 

• SCAA Grading Standards for physical evaluation of green coffees

Class Objectives• List at least 4 reasons for green coffee grading and 

describe why each reason is important.• Identify and explain key parameters of SCAA Green 

Arabica Coffee Classification System and methods.• Practice green coffee defect identification using formal 

terminology. • Use the SCAA Green Coffee Grading Handbook to identify 

defects correctly, stating how the defects occur and what can help avoid the defect.

• Discuss various testing methods and grading equipment. 

Purpose of Grading

Defining Purchase Contract Terms– Both defect count & bean size standards– Global Specialty Industry standards– “Specialty Washed Arabica” defined worldwide

• Quality Control– Matching pre‐shipment to arrival samples– Premiums earned for high quality

Why do we grade green

coffee?

SCAA Green Arabica Coffee Classification System

1. 16 Defects (6 Primary, 10 Secondary)2. Current standard for “Specialty” Washed Arabica 

permits no Primary Defects, and up to five Secondary Defects

3. Arabica Green Grading Book defines defects, SCAA defines grade standards

4. Arabica Green Grading Test sheet used to record evaluation of green coffee samples

Arabica Green Grading Test Sheet

Used by Q Graders to evaluate a 350 gram during sample based on:

• Defect Count• Color• Odor• Moisture Content

Part One: Defect Evaluation16 Most Common Green Coffee Defects

As Defined by SCAA & CQI

6 Primary and 10 Secondary Defects, classified based on effect on cup qualityIdentify the following for each defect:

□ Defect name(s)□ Classification Type (Primary or Secondary)□ Effect on cup quality□ Other risks□ Potential causes□ Method of correction/avoidance

Station instructors available to answer questions at tables

Primary Defect(1 = 1)

Full Black

Primary Defect(1 = 1)

Full Sour

Primary Defect (1 = 1)

Foreign Material

Primary Defect (1 = 1)Fungus Damage

Primary Defect (1 = 1)Cherry Pod

PRIMARY DEFECTSINSTRUCTIONS:

• GENTLY pour the sample onto your grading mat

• Avoid SPILLING OR DROPPING beans

Classification Exercise

1. Pull out the defective beans2. Make a separate pile for each defect3. Check your results against the pictures in the book4. Record your results on the sheet5. Work with your table lead if you have questions.

Remember: If it isn’t in the book,

it’s not an SCAA defect!

SECONDARY DEFECTS

Secondary Defect (3 = 1)

Partial Black

Secondary Defect(3 = 1)

Partial Sour

Secondary Defect (5 = 1)Cherry Hull/Husk

Hull Husk

Secondary Defect (5 = 1)Floater

Classification Exercise

• Pull out the defective beans• Make a separate pile for each defect• Check your results against the pictures in the book• Work with your table lead if you have questions.

Remember: If it isn’t in the book,

it’s not an SCAA defect!

Secondary Defect (5 = 1)Immature

Secondary Defect (5 = 1)

Withered

THE BERRY BORER BEETLE- Hypothenemus Hampei

Secondary Defect (10 = 1)

Slight Insect Damage

Primary Defects (5 = 1)

Severe Insect Damage

Secondary Defect (5 = 1)Parchment

Secondary Defect(5 = 1)

Shell

Secondary Defect (5 = 1)

Broken/Chipped/Cut

Cut in wet milling process Cut in dry milling process

Remember: If it isn’t in the book,

it’s not an SCAA defect!

Classification Exercise

1. Pull out the defective beans2. Make a separate pile for each defect3. Check your results against the pictures in the book4. Record your results on the sheet5. Work with your table lead if you have questions.

Discussion

POP QUIZ! Which is the more severe defect of the following pairs:

(A)  Partial sour  or (B)  Floater(A) Full black  or (B) Foreign matter

(A) Slight Insect Damage or (B) Broken/Chipped/Cut

Have you ever seen any of these defects in a coffee sample?

10 minute break

Part Two:General Physical Evaluation

• Several physical attributes of green coffee are directly related to quality (SCAA Grading Standards):– Color– Odor– Moisture content (by weight)

• Other physical traits have a significant impact on market value (Not SCAA Grading Standards):– Bulk Density– Bean size

Physical Evaluation: Color

• Green bean color can vary depending on several factors:□ Moisture content□ Bean density□ Age of green coffee□ Processing method (i.e. washed, natural, 

pulped natural, etc.)□ Exposure to sunlight□ Storage or transportation conditions

Physical Evaluation: ColorGenerally,

a deep, blue-green color is desirable, and

a faded, straw yellow color is undesirable

Physical Evaluation: Odor• Non‐coffee odor taints are undesirable• Water in dried coffee risks absorption of foreign odors

• Contamination in storage or transit• Non food grade jute bags• Proximity to volatile fumes 

such as petrol or smoke• Improper drying and/or 

storage may lead toodor‐causing mildew or mold 

Physical Evaluation: Odor

• Improper drying and/or storage may lead to mildew or mold damage.  – Ochratoxin A (OTA)  

• Mycotoxin• Grains stored in high humidity for long periods• Can suppress human immune system• Has been linked to disease • Do not “cook” out of foods

– Temporarily restricted import of coffees 

Photo: UN-FAO

Physical Evaluation: Moisture Content

• Moisture content critical to integrity of green coffee– Exceptionally high moisture: risk of mildew or mold

– Exceptionally low moisture: poor uniformity and risk of flavor loss

• SCAA Standard– Natural process 10‐13%– Washed coffee 10‐12%

Physical Evaluation: Moisture Content

• Affects bean density, but is easily lost in roasting

• Moisture content measuring equipment considerationsAccuracyPrice rangeEase of usePortability

Physical Evaluation: Bulk Density

• Not included in SCAA green coffee grading standards• Density = Mass divided by volume (i.e., g/mL)• Density may be determined by cellular structure, 

moisture content, or both• Density has a relationship to quality, as more dense 

beans have more  organic material developed into soluble solids during roasting.  

• Uniform density within a lot is crucial when roasting

HIDE THIS SLIDE FOR SCAA CLASSES

Physical Evaluation: Bulk Density

• Density as a factor in the roasting process:– Generally, heat transfers more slowly into dense beans, and more quickly into porous beans

– As beans lose moisture, density decreases• Porous beans with high moisture content acquire heat 

slowly early in the roast, but very quickly once moisture is lost (near first crack)

• Very high grown beans with high cellular density roast also acquire heat slowly, early, but roast more evenly once moisture is lost (near first crack)

HIDE THIS SLIDE FOR SCAA CLASSES

Physical Evaluation: Screen Size

• Not included in SCAA green coffee grading standards

• Sorting (aka “Grading”) uses screens with holes measured in 64ths of an inch

• Each producing country has unique system for classifying beans by size:– Ex.: Kenya “AA” = 17/18 Scr., “AB” = 15/16 Scr.

– Ex.: Colombia “Supremo” = > 17 Scr., “Excelso” = 15/16 Scr. 

Physical Evaluation: Screen Size

• Larger beans generally sell for higher prices• Smaller beans generally sell for lower prices• “Peaberry” beans marketed well in some countries (Tanzania, Kenya) but generally do not sell well

• Factors in the roasting process:• Different sizes roast at different rates• Uniformity within a lot is crucial for even

roasting

Discussion Questions

• What was the most difficult concept to learn?

• What did you learn today that you can apply to your business?

Turn in Grading Sheet

• Make sure everything filled out and calculated correctly (this WILL be graded)

• Write your name• Write your station instructor’s name• Take a photo of it, if you want, before you turn it in.• Blank copies for you to take home• TAKE YOUR BOOKS WITH YOU!• TAKE YOUR MATS WITH YOU!

Evaluation for Roasters Guild Certificate

andCoffee Taster Certificate

• Will have a final exam– study!• RG Level 1 final will be available online by October, 2014– Candidates must also submit ONE GRADING SHEET‐completed thoroughly and have both primary and secondary defects

Certificates and Credits

• Must have/create an online profile at SCAA.org using primary email address to receive certificate credit this takes 2-4 weeks

Resources for Further Study

Other classes to prepare for the Coffee Taster Certificate

– GE153 Le Nez du Café Aroma of Coffee– GE154 Sensory Skills Test– GE255 Organic Acids & The Chemistry of Coffee– GE103, GE202, GE303 (Cupping classes)– GE201 The SCAA Cupping Form & Peer Calibration