Kenya Coffee School

From Seed to Cup – Barista Skills & Specialty Coffee

Revision Questions and Answers

21. What is green coffee?

Answer: Green coffee is the raw, unroasted coffee bean obtained after the parchment layer has been removed through hulling.

Explanation: Green coffee is stable for storage and transport and is the stage at which grading, quality evaluation, and export are usually carried out.

Exam Tip: Green coffee is not green in colour; it is typically bluish-green or pale green.

22. What defects are checked during coffee grading?

Answer: Common defects include:

• Black beans
• Sour beans
• Broken beans
• Insect-damaged beans
• Immature beans
• Shell beans
• Stones and foreign matter

Explanation: The fewer the defects, the higher the coffee quality and market value.

Exam Tip: Defect-free coffee generally receives a higher market price.

23. What factors determine coffee quality?

Answer: Coffee quality is influenced by:

• Variety
• Altitude
• Soil fertility
• Climate
• Harvesting practices
• Processing method
• Drying
• Storage
• Roasting
• Brewing technique

Explanation: Quality is built throughout the entire value chain—from the farm to the final cup.

Exam Tip: Every stage affects the final flavour.

24. Explain bean density.

Answer: Bean density refers to how compact and hard a coffee bean is.

Explanation: High-density beans usually develop at higher altitudes and often produce more complex flavours during roasting.

Exam Tip: Higher altitude generally results in denser beans.

25. Why is proper storage important?

Answer: Proper storage:

• Prevents mould
• Maintains moisture levels
• Preserves flavour
• Protects against pests
• Extends shelf life

Explanation: Green coffee should be stored in a cool, dry, well-ventilated environment away from strong odours.

Exam Tip: Poor storage can ruin excellent coffee.

26. What is cupping?

Answer: Cupping is the standardized method of evaluating coffee aroma, flavour, acidity, body, sweetness, balance, and aftertaste.

Explanation: Coffee professionals use cupping to compare and assess coffee quality objectively.

Exam Tip: Cupping is the international language of coffee quality evaluation.

27. Define specialty coffee.

Answer: Specialty coffee is coffee that scores 80 points or above out of 100 during a standardized sensory evaluation and has minimal physical defects.

Explanation: Specialty coffee is produced with exceptional care from cultivation through brewing.

Exam Tip: Specialty coffee emphasizes quality, traceability, and consistency.

28. What cupping score qualifies coffee as specialty?

Answer: A score of 80 points or higher out of 100.

Explanation: Coffee scoring below 80 is generally classified as commercial-grade coffee.

Exam Tip: 80+ = Specialty Coffee.

29. Name five coffee aroma descriptors.

Answer: Examples include:

• Floral
• Fruity
• Chocolate
• Nutty
• Caramel

Other descriptors include citrus, berry, herbal, spicy, and vanilla.

Explanation: Aromas help identify coffee origin and processing characteristics.

Exam Tip: Smell contributes significantly to flavour perception.

30. Explain coffee traceability.

Answer: Traceability is the ability to track coffee from the farm to the final consumer.

Explanation: It records information such as:

• Farm location
• Variety
• Harvest date
• Processing method
• Storage
• Export
• Roasting

Exam Tip: Traceability builds consumer trust and supports premium pricing.

31. What happens during coffee roasting?

Answer: During roasting:

• Moisture evaporates.
• Sugars caramelize.
• Proteins react with sugars (Maillard reaction).
• Aromatic compounds develop.
• Beans expand and become brittle.

Explanation: Roasting transforms green coffee into the aromatic beans used for brewing.

Exam Tip: Roasting develops flavour but cannot correct poor-quality green coffee.

32. What is the first crack?

Answer: The first crack is the stage during roasting when expanding steam causes the beans to crack audibly.

Explanation: It marks the beginning of light roast development.

Exam Tip: Most specialty coffees are roasted shortly after the first crack.

33. What is the second crack?

Answer: The second crack occurs later in roasting when the bean structure begins to break down further.

Explanation: It signals darker roast development with more oils appearing on the bean surface.

Exam Tip: Roasting well into the second crack can reduce origin flavours.

34. Differentiate between light, medium, and dark roast.

Answer:

Explanation: Different roast levels highlight different flavour profiles.

Exam Tip: Light roasts preserve more of the coffee’s origin characteristics.

35. What is roast development time?

Answer: Roast development time is the period between the first crack and the end of the roast.

Explanation: This stage determines sweetness, body, and flavour balance.

Exam Tip: Too little or too much development affects cup quality.

36. What causes underdeveloped coffee?

Answer: Underdeveloped coffee is caused by:

• Roasting too quickly
• Ending the roast too early
• Insufficient heat development

Explanation: The coffee may taste grassy, sour, or cereal-like.

Exam Tip: Green or peanut-like flavours often indicate underdevelopment.

37. What causes baked coffee?

Answer: Baked coffee results from roasting too slowly or holding the beans at low temperatures for too long.

Explanation: The coffee loses vibrancy and tastes flat or dull.

Exam Tip: Good roasting requires balanced heat application.

38. Why should roasted coffee rest before brewing?

Answer: Resting allows excess carbon dioxide (CO₂) to escape, improving extraction and flavour.

Explanation: Freshly roasted coffee releases gas for several days.

Exam Tip: Espresso often performs best after 5–14 days of resting, depending on the roast profile.

39. What gases are released after roasting?

Answer: The primary gas released is carbon dioxide (CO₂).

Small amounts of other volatile gases are also produced.

Explanation: CO₂ affects crema formation and extraction quality.

Exam Tip: Fresh coffee contains much more CO₂ than older coffee.

40. What is degassing?

Answer: Degassing is the gradual release of carbon dioxide from roasted coffee after roasting.

Explanation: Controlled degassing improves brewing consistency, especially for espresso.

Exam Tip: Coffee bags often include a one-way valve to allow CO₂ to escape while preventing oxygen from entering.