Professional coffee education

This curriculum is designed for the Kenya Coffee School, integrating local expertise in high-acid Arabica with international specialty standards. It is structured into 20 comprehensive articles (modules), each focusing on a specific pillar of professional coffee education.
Part 1: Coffee Chemistry & Physiology
Article 1: The Molecular Makeup of the Green Bean
Before heat touches the coffee, a complex chemical laboratory exists inside the green bean. Kenyan coffee is renowned for its phosphoric acidity and dense cell structure. This article explores the primary precursors: carbohydrates (sugars like sucrose), lipids (coffee oils), and nitrogenous compounds (caffeine and trigonelline). Students will learn how the altitude of Mount Kenya and the Aberdares influences the concentration of chlorogenic acids (CGAs), which are vital for the coffee’s final antioxidant properties and flavor profile.
Article 2: The Physiology of Taste and Olfaction
To be a taster, one must understand the biological “tools.” This module breaks down how the tongue perceives the five basic tastes (sweet, sour, salty, bitter, umami) and how the olfactory system detects thousands of volatile aromatic compounds. We focus on “retronasal olfaction”—the aroma perceived while the coffee is in the mouth—which is the secret to identifying complex Kenyan notes like blackcurrant and grapefruit.
Article 3: Water Chemistry in Extraction
Coffee is 98-99% water. This article examines how mineral content (Ca^{2+}, Mg^{2+}) and alkalinity affect the extraction of Kenyan beans. High alkalinity can “buffer” or mute the vibrant acidity typical of Nyeri or Kirinyaga coffees. Students will learn the chemistry of Total Dissolved Solids (TDS) and how to balance water hardness to ensure the cup reflects the farm’s true potential.
Article 4: Chemical Changes During Roasting
Roasting is essentially a series of endothermic and exothermic chemical reactions. We dive into the Maillard Reaction, where amino acids and reducing sugars create melanoidins (browning), and Caramelization, which develops sweetness. We also track the degradation of chlorogenic acids into quinic acid, explaining why over-roasted coffee loses its “Kenyan” brightness and becomes metallic or bitter.
Part 2: Sensory Analysis Foundations
Article 5: The SCA Flavor Wheel & Sensory Lexicon
Using the World Coffee Research (WCR) Lexicon, students learn a standardized language. This article teaches how to move from vague descriptions (“it tastes good”) to specific sensory descriptors (“citric acidity,” “stone fruit,” “jasmine”). We emphasize the specific “Kenyan profile” attributes, training the palate to distinguish between various phosphoric and malic acidities.
Article 6: Identifying Sensory Defects
A professional must identify what shouldn’t be there. This module covers “off-flavors” caused by chemical or biological failures: Phenol (chemical/medicine), Potato Defect (common in East African Great Lakes regions), and Ferment (over-ripe/rotten). We discuss the chemical triggers for these defects and how they impact the lot’s commercial value.
Article 7: Acid Profiling and Intensity
Kenya is the “Land of Acidity.” This article focuses on identifying and quantifying different organic acids. Students will participate in “spiked water” tests to recognize Citric (lemon/lime), Malic (apple), Tartaric (grape), and Acetic (vinegar) acids. We teach how to differentiate between “brightness” (positive) and “sourness” (negative).
Article 8: Mouthfeel and Body Dynamics
Beyond flavor is the physical sensation of the coffee. This article explores the lipids and fibers that contribute to “body.” We define “Tactile” terms: Is the coffee “Tea-like” (common in some Embu SL-28s), “Syrupy,” or “Creamy”? Understanding the “weight” on the palate is essential for both filter and espresso evaluation.
Part 3: The Art and Science of Roasting
Article 9: Thermodynamics and Heat Transfer
Roasting is the management of heat. This module explains Conduction (contact with the drum), Convection (hot air flow), and Radiation. Students will learn how to manipulate these forces to ensure the dense Kenyan bean is cooked evenly from the core to the surface, avoiding “scorching” or “tipping.”
Article 10: Roast Profiling and the Rate of Rise (RoR)
The “Flight Path” of a roast determines its flavor. This article introduces data logging software (like Artisan or Cropster). We focus on the Rate of Rise—the speed at which the bean temperature increases. We discuss why a “crashing” RoR at the end of a roast can lead to “baked” flavors, destroying the delicate floral aromatics of a premium SL-34 variety.
Article 11: The Stages of a Roast: Drying to Finish
We break the roast into three phases: Drying, Yellowing (Maillard), and Development (Post-crack). For Kenyan coffees, the development time (DTR) is critical; too short, and it’s grassy; too long, and you lose the terroir. This article provides a blueprint for “Roasting for Filter” vs. “Roasting for Espresso.”
Article 12: Roastery Management and Quality Control
A roaster is also a production manager. This article covers green coffee storage (maintaining 10-12% moisture), moisture loss calculations, and “Color Tracking” using Agtron scales. We emphasize the importance of “Sample Roasting” to evaluate a crop before committing to a 60kg production batch.
Part 4: Coffee Quality Analysis (CQA)
Article 13: Green Coffee Grading (The Kenya System)
Kenya uses a unique grading system based on bean size (AA, AB, C, PB, etc.). This article demystifies the system, explaining how “E” (Elephant beans) differ from “AA,” and how screen size correlates to density and quality. We also cover the physical inspection for primary defects (black beans, sour beans) and secondary defects (withered, nipped).
Article 14: Moisture and Density Measurement
High-quality Kenyan coffee is grown at high altitudes, leading to high density. This module teaches students how to use moisture meters and density kits. We explain why a bean with 13% moisture is at risk of mold (Ochratoxin A) and why density is the best predictor of how much heat a bean can “take” in the roaster.
Article 15: The Nairobi Coffee Exchange (NCE) Protocols
Understanding the local market is key. This article explores how coffee is valued at the NCE. We discuss the role of the “Liquorer” (the Kenyan term for a cupper) and how sensory scores directly translate into the “Hammer Price” at auction.
Article 16: Statistical Consistency in Quality Control
Quality is about repeatability. This module teaches students how to use “Triangulation” tests (identifying the odd cup out of three) to ensure a roastery’s output is consistent. We introduce basic statistical tools to track “drift” in sensory quality over a season.
Part 5: Advanced Cupping & Espresso Evaluation
Article 17: The SCA Cupping Protocol
This is the industry standard. This article provides a step-by-step guide: fragrance (dry), aroma (wet), breaking the crust, and the four-stage tasting process (Hot, Warm, Room Temp). Students learn to fill out the SCA score sheet, grading coffee on a scale of 0 to 100.
Article 18: Calibration: Finding the “North Star”
A cupper cannot work in a vacuum. This article focuses on Calibration—the process of aligning your scores with other professionals. We discuss why a panel of cuppers might differ in their scores and how to reach a consensus for commercial grading.
Article 19: Espresso Cupping and Deconstruction
Espresso is different; its high concentration changes how we perceive flavor. This article teaches “Espresso Cupping,” where we evaluate the “Three Parts” of a shot: the Ristretto (acid/salt), the Heart (sweetness), and the Tail (bitter/ash). We discuss how to “cup” espresso by diluting it with water to reveal defects hidden by intensity.
Article 20: Dialing In: From Cupping Table to Bar
The final module bridges the gap between the lab and the cafe. We teach how to take the results of a sensory analysis and apply them to an espresso machine. If a Kenyan coffee cupped with “Bright Citrus” but tastes “Sour” as an espresso, students learn how to adjust grind size, temperature, and yield to “dial in” the perfect shot.