Kenya Coffee School Curriculum & Professional Training Division

Course Overview

Course Title: Contemporary Fermentation & Barrel-Aging Techniques in Specialty Coffee Code: KCS-EXP-302 Duration: 3 Days (24 Total Instructional Hours) Target Audience: Estate Managers, Processors, Roasters, Head Baristas, and Coffee Entrepreneurs Prerequisites: Basic understanding of post-harvest processing (Washed/Natural) and introductory cupping skills.

Day 1: Biochemistry of Fermentation & In-Cask Maceration

Objective: Understand the biochemical pathways of processing, yeast activity, and green bean moisture absorption dynamics.

  • 08:30 – 10:00 | Theory: Foundations of Contemporary Fermentation
    • Microbial ecology: Wild yeast vs. inoculated saccharomyces strains
    • Controlling Brix (18°–22°), pH curves (4.3–4.5 terminal threshold), and water activity (a_w)
    • Anaerobic vs. aerobic environments and their structural impact on SL28/SL34 cultivars
  • 10:15 – 12:30 | Lab Session: Monitoring & Measuring Tools
    • Hands-on use of refractometers, digital pH probes, water activity meters, and density columns
    • Setting up controlled pilot fermentation batches with fresh coffee cherry/cascara
  • 13:30 – 15:00 | Theory: Introduction to Barrel Aging & Wood Chemistry
    • Cask selection: Seasoned wine oak (French vs. American) vs. spirit barrels
    • Physics of green coffee absorption (820 – 850\text{ g/L} density thresholds)
    • Hygroscopic behavior, cell wall expansion, and volatile compound uptake
  • 15:15 – 17:00 | Sensory Calibration: Acid Identification & Defect Mapping
    • Cupping: Isolating Tartaric, Malic, Lactic, and Acetic acid profiles
    • Identifying over-fermentation defects (stinker beans, wild vinegars, phenol)

Day 2: Barrel-Aging Protocols, Cellar Control & “The Coffee Wine”

Objective: Master environmental controls, barrel maintenance, and the execution of the “Coffee Wine” conditioning profile.

  • 08:30 – 10:30 | Practical: Cask Inspection, Preparation & Loading
    • Inspecting oak barrels for integrity, wetness, and microbial cleanliness
    • Calculating fill ratios (70–80% ullage) and loading green beans (Screen 17/18 AA)
  • 10:45 – 12:30 | Workshop: Cellar Management & Microclimate Mechanics
    • Temperature control (15^\circ\text{C} – 18^\circ\text{C}) and relative humidity (55\% – 65\%\text{ RH})
    • Barrel rotation schedules (180° agitation mechanics) and sampling methods
    • Preventing mold activation (Aspergillus) and maintaining a_w < 0.62
  • 13:30 – 15:30 | Lab Session: Cascara Wine & Co-Fermentation
    • Utilizing cherry pulp/cascara for wine conditioning bases
    • Formulating direct macerations and wine-infused soaking protocols
  • 15:45 – 17:00 | Sensory Session: Barrel Aging Benchmark Cupping
    • Evaluating 14-day, 30-day, and 60-day wine-aged green coffee samples
    • Tracking wood tannin absorption versus origin acidity retention

Day 3: Thermal Stabilization, Roast Profiling & Commercial Value Addition

Objective: Learn to post-dry, roast, and package barrel-aged coffee without destroying volatile wine esters.

  • 08:30 – 10:30 | Practical: Post-Aging Stabilization & Drying
    • Unloading casks and measuring moisture content (>12.5\%)
    • Shaded air-drying protocols to re-stabilize green beans back to 11.2\% – 11.5\% moisture
  • 10:45 – 13:00 | Roasting Lab: Heat Application for Wine-Aged Beans
    • Modifying roast curves: Gentle initial conduction to protect delicate fruit esters
    • Managing early drum temperatures, charge temps, and airflow timing
    • Executing 3 test roasts (Light/Medium/Development drop points) on drum roasters
  • 14:00 – 15:30 | Cupping & Evaluation: Final Batch Analysis
    • Blind cupping of Day 3 roast profiles: Evaluating “The Coffee Wine” cup attributes
    • Measuring solubilities, extraction yield, and final beverage balance
  • 15:45 – 17:00 | Business Integration & Certification:
    • Regulatory compliance, labeling requirements, and premium marketing
    • Certificate presentation and course wrap-up