1.4 Coffee Varietals & Green Quality Grading
Key Takeaways
- Typica and Bourbon represent the foundational heirloom lineages of Coffea arabica, known for clean sweetness and complex organic acidity.
- Geisha (Gesha) is a high-altitude Ethiopian landrace cultivar famous for delicate jasmine florals, bergamot citrus, tea-like body, and top-tier cupping scores.
- Catimor hybrids (e.g. Castillo, Variedad Colombia) cross Caturra with Hibrido de Timor (Arabica x Robusta) to combine Coffee Leaf Rust resistance with high yield.
- The SCA Green Coffee Grading Standard evaluates a 350g sample, permitting zero Category 1 Primary Defects for a Specialty Grade classification.
- Specialty Grade green coffee allows a maximum of 5 Category 2 Secondary Defects per 350g, requires 10–12% moisture, and must score 80+ points in cupping.
1.4 Coffee Varietals & Green Quality Grading
Quick Answer: Arabica coffee varietals stem from two foundational lineages: Typica and Bourbon. Mutations and hybridizations have produced celebrated cultivars ranging from high-yield dwarfs (Caturra, Catuai) and disease-resistant Timor hybrids (Castillo) to pristine landraces like Geisha. Green coffee quality is evaluated using the SCA Green Coffee Grading Standard on a 350g sample: Specialty Grade permits 0 Category 1 Primary Defects, no more than 5 Category 2 Secondary Defects, 10–12% moisture, and an 80+ point cup score.
Within Coffea arabica, genetic diversity manifests in hundreds of distinct cultivars (cultivated varieties) and varietals (botanical varieties). A cultivar's genetic lineage dictates tree morphology, cherry yield, disease resistance, and raw bean composition. Furthermore, before green coffee enters roasteries and espresso bars, it must undergo rigorous physical inspection under the SCA Green Coffee Grading Standard. Mastering varietal lineages and defect classification is essential for green buying, sensory evaluation, and bar management.
Arabica Varietal Taxonomy & Lineages
Almost all modern Arabica cultivars trace their genetic heritage back to two primary historical lineages introduced from Ethiopia via Yemen: Typica and Bourbon.
[ Wild Ethiopian Heirloom Landraces ]
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┌───────────────┴───────────────┐
[ Typica Lineage ] [ Bourbon Lineage ]
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┌─────────────┼─────────────┐ ┌───────┼───────┐
Maragogype San Ramon Java Caturra SL28 Jackson
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Mundo Novo (Typica x Bourbon) ─────────────┘
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Catuai (Mundo Novo x Caturra)
1. The Typica Lineage
Typica is the original Arabica coffee transported by the Dutch from Yemen to Java and subsequently across the Americas in the early 18th century.
- Morphology: Tall tree with conical form, long lateral branches, low productivity, and characteristic bronze-colored young tip leaves.
- Cup Profile: Renowned for supreme cup cleanliness, refined sweetness, and delicate acidity, though highly susceptible to Coffee Leaf Rust (Hemileia vastatrix).
2. The Bourbon Lineage
Bourbon developed from trees introduced by French missionaries to the island of Réunion (formerly Île Bourbon) in the Indian Ocean.
- Morphology: Tall tree with broader, broader leaves, green-colored young tips, and rounded cherries. Yields 20–30% more fruit than Typica.
- Cup Profile: Exceptional complex acidity, intense sweetness, and layered notes of caramel, red fruit, and chocolate.
3. Key Mutations, Hybrids & Landraces
- Geisha / Gesha: An Ethiopian landrace collected from the Gesha forest in 1930, naturalized in Panama at Hacienda La Esmeralda. Grown at extreme altitudes (>1,600m), it features elongated beans and produces world-record cupping scores defined by intense jasmine, orange blossom, bergamot, peach, and tea-like elegance.
- Caturra: A single-gene dwarf mutation of Bourbon discovered in Brazil in 1937. Its compact size permits higher planting density, dramatically increasing hectare yield while preserving high citric acidity.
- Catuai: An artificial hybrid cross between Caturra and Mundo Novo created in Brazil (1949). Highly wind-resistant dwarf plant yielding sweet, balanced cups.
- SL28 & SL34: Selected in Kenya by Scott Laboratories in the 1930s. Drought-resistant selections famous for tartaric/phosphoric blackcurrant acidity.
- Hibrido de Timor (Timor Hybrid) & Catimor: A spontaneous interspecific cross between C. arabica and C. canephora (Robusta) discovered on Timor Island. Inherited Robusta's dominant rust-resistance genes ($S_H3$). Crossed with Caturra to create Catimor. Derivatives such as Castillo and Variedad Colombia provide high rust resistance and productivity with respectable specialty cup quality.
SCA Green Coffee Grading Standard
The Specialty Coffee Association (SCA) establishes a standardized protocol for evaluating raw green coffee before roasting. Green grading identifies physical defects that degrade cup flavor or damage equipment.
Grading Protocol Requirements
- Sample Size: Exactly 350 grams of green coffee.
- Environment: Evaluated on a flat, neutral blue or white surface under full-spectrum lighting delivering a minimum illumination of 1,200 lux.
- Moisture Content Target: Must measure strictly between 10.0% and 12.0%.
Category 1 vs. Category 2 Green Coffee Defects
Defects are divided into Category 1 (Primary Defects)—severe flaws that ruin cup flavor or damage equipment—and Category 2 (Secondary Defects)—minor structural or aesthetic flaws.
| Defect Category | Defect Type | Physical Description | Impact on Roasted Cup |
|---|---|---|---|
| Category 1 (Primary) | Full Black | Bean is >50% opaque black, shriveled, dead | Pungent, foul, fishy, fermented, ashy bitterness |
| Full Sour | Bean is dark yellow/brown, fermented interior | Sour, vinegary, acrid, fermented onion | |
| Dried Pod / Cherry | Whole dried outer cherry husk intact around seed | Phenolic, moldy, harsh astringent, woody | |
| Fungus Damage | Visible yellow/white mold spores or powdery crust | Musty, earthy, toxic, moldy cup | |
| Foreign Matter | Stones, sticks, metal, glass, or soil present | Severe mechanical damage to roasters/grinders | |
| Severe Insect | 3 or more visible insect bore holes | Turpentine, dirty, defective flavor | |
| Category 2 (Secondary) | Partial Black / Sour | <50% of bean surface discolored black or sour | Mild fermented or sour off-notes |
| Parchment / Shell | Fragment of parchment shell or hollow thin bean | Uneven roasting, burnt chaff flavor | |
| Broken / Chipped | Bean cracked, split, or missing >1/3 of body | Scorching, uneven roast development | |
| Immature (Quaker) | Unripe bean with silver skin attached tightly | Pale roast color; peanutty, grassy, cereal cup | |
| Slight Insect | 1 or 2 small insect bore holes | Slight loss of cup sweetness and clarity |
SCA Green Coffee Grade Classifications
To achieve official Specialty Grade (Grade 1) status, a coffee sample must meet rigorous quantitative criteria:
- Category 1 Primary Defects: 0 allowed in the 350g sample.
- Category 2 Secondary Defects: Maximum 5 full equivalent defects allowed per 350g sample.
- Moisture Content: Strictly 10.0% to 12.0%.
- Quaker Limit: 0 quakers permitted in a 100g roasted sample.
- Cupping Score: Must achieve a minimum score of 80.0 points or higher on the 100-point SCA Cupping Form, exhibiting distinct origin attributes and zero sensory cup flaws/defects.
- Premium Grade (Grade 2): Max 8 total full defects; 10–13% moisture; cup score 70–79.75.
- Exchange / Commercial Grade (Grade 3/4/5): >8 defects; moisture non-conforming; cupping below 70 points.
Under the official SCA Green Coffee Grading Standard, how many Category 1 (Primary) defects are permitted in a 350-gram sample for Specialty Grade classification?
What is the maximum number of Category 2 (Secondary) full defects allowed in a 350g green sample for Specialty Grade coffee, and what is the minimum cupping score requirement?
Which coffee cultivar lineage possesses resistance to Coffee Leaf Rust (Hemileia vastatrix) due to genetic introgressions from a natural Arabica x Robusta hybrid?
Which Arabica varietal is renowned for its elongated bean morphology and a world-record cup profile featuring intense jasmine florals, bergamot citrus, and tea-like elegance?