Kenya Coffee School

From Seed to Cup – Barista Skills & Specialty Coffee

Revision Questions and Answers

Part 1: Questions 1–20 (Coffee Farming & Processing)

1. What are the two main coffee species grown commercially?

Answer: The two major coffee species grown commercially are Arabica (Coffea arabica) and Robusta (Coffea canephora).

Explanation: Arabica accounts for about 60–70% of the world’s coffee and is valued for its delicate flavours and aroma. Robusta is more resistant to pests and diseases and contains almost twice as much caffeine.

Exam Tip: Remember:

• Arabica = Higher quality, higher altitude.
• Robusta = Stronger, more caffeine, lower altitude.

2. Differentiate between Arabica and Robusta coffee.

Answer:

Explanation: Arabica is preferred in specialty coffee because of its complex flavours.

Exam Tip: Most Kenyan coffee is Arabica.

3. Name five major coffee-growing regions in Kenya.

Answer:

• Kiambu
• Murang’a
• Kirinyaga
• Nyeri
• Embu

Other regions include Meru, Kericho, Nakuru, Machakos, Bungoma and Trans Nzoia.

Explanation: These regions have fertile volcanic soils and favourable rainfall.

Exam Tip: Central Kenya produces much of the country’s premium specialty coffee.

4. What soil pH is ideal for coffee production?

Answer: The ideal soil pH is 5.5–6.5.

Explanation: This pH range allows efficient nutrient uptake.

Exam Tip: Very acidic or alkaline soils reduce nutrient availability.

5. Explain the importance of shade trees in coffee farming.

Answer: Shade trees:

• Reduce heat stress.
• Conserve soil moisture.
• Improve biodiversity.
• Reduce erosion.
• Add organic matter.

Explanation: Shade supports climate-smart coffee production.

Exam Tip: Too much shade can reduce yields.

6. What is the difference between orthotropic and plagiotropic branches?

Answer:

• Orthotropic branches grow vertically and form the main stem.
• Plagiotropic branches grow horizontally and bear flowers and cherries.

Explanation: Coffee cherries are mainly produced on plagiotropic branches.

Exam Tip: Horizontal branches = fruit production.

7. List five signs of nutrient deficiency in coffee plants.

Answer:

• Yellow leaves.
• Stunted growth.
• Poor flowering.
• Small cherries.
• Premature leaf drop.

Explanation: Deficiencies commonly involve nitrogen, potassium or magnesium.

Exam Tip: Leaf colour often indicates nutrient status.

8. Explain the coffee flowering process.

Answer: After rainfall, flower buds develop into white blossoms. These are pollinated and later develop into coffee cherries.

Explanation: Flowering determines the potential crop.

Exam Tip: Healthy flowering leads to higher yields.

9. Name four common coffee pests.

Answer:

• Coffee Berry Borer
• Antestia Bug
• Coffee Leaf Miner
• Mealybugs

Explanation: These pests reduce both yield and quality.

Exam Tip: Integrated Pest Management (IPM) is the preferred control method.

10. Name four common coffee diseases.

Answer:

• Coffee Leaf Rust
• Coffee Berry Disease (CBD)
• Bacterial Blight
• Root Rot

Explanation: Disease management includes resistant varieties, sanitation and timely spraying.

Exam Tip: CBD is a major disease affecting Arabica coffee in Kenya.

11. Why is selective picking important?

Answer: Selective picking ensures that only ripe cherries are harvested, improving coffee quality and cup flavour.

Explanation: Mixing ripe and unripe cherries lowers the final quality.

Exam Tip: Specialty coffee requires selective harvesting.

12. What is the difference between ripe, underripe and overripe cherries?

Answer:

• Ripe: Bright red (or yellow depending on variety), high sugar content.
• Underripe: Green, low sugar, poor flavour.
• Overripe: Dark red or black, may ferment or spoil.

Explanation: Only ripe cherries produce the best quality coffee.

Exam Tip: Harvest only ripe cherries for specialty coffee.

13. Explain the washed (wet) processing method.

Answer: The cherries are:

1. Pulped.
2. Fermented.
3. Washed.
4. Dried.
5. Hulled.

Explanation: This method produces clean, bright and high-quality coffees.

Exam Tip: Kenya is famous for washed coffee processing.

14. Explain the natural (dry) processing method.

Answer: Whole cherries are dried before removing the outer layers.

Explanation: Natural coffees often have fruity flavours and heavier body.

Exam Tip: Requires careful drying to prevent mould.

15. What is honey processing?

Answer: The skin is removed, but some mucilage remains on the bean during drying.

Explanation: Produces a balance between washed and natural coffee characteristics.

Exam Tip: Honey processing does not involve bee honey.

16. Why is fermentation important?

Answer: Fermentation removes sticky mucilage and develops flavour precursors.

Explanation: Controlled fermentation improves cup quality.

Exam Tip: Over-fermentation causes undesirable flavours.

17. What moisture content should green coffee reach before storage?

Answer: 10–12% moisture content.

Explanation: Proper moisture prevents mould and maintains bean quality.

Exam Tip: High moisture leads to spoilage during storage.

18. Explain the purpose of drying beds.

Answer: Drying beds:

• Improve air circulation.
• Ensure even drying.
• Reduce contamination.
• Protect coffee quality.

Explanation: Raised beds are commonly used for specialty coffee.

Exam Tip: Coffee should be turned regularly during drying.

19. What causes mould during drying?

Answer:

• High moisture.
• Poor ventilation.
• Rain exposure.
• Slow drying.
• Thick layers of cherries.

Explanation: Mould creates defects and may produce harmful toxins.

Exam Tip: Dry coffee evenly to the recommended moisture level.

20. Define coffee parchment.

Answer: Coffee parchment is the thin protective layer that surrounds the green coffee bean after processing and drying.

Explanation: The parchment is removed during the hulling process before grading and roasting.

Exam Tip: Coffee Journey: Seed → Seedling → Tree → Flower → Cherry → Pulping → Fermentation → Washing → Drying → Parchment Coffee → Hulling → Green Bean → Roasting → Grinding → Brewing → Cup.