This Calibration Guide ensures that the Wet Mill Manager (who controls the chemistry) and the Lab Q-Grader (who evaluates the sensory) are speaking the same language. Use this to troubleshoot why a lot didn’t hit the “Phosphoric” peak.
The Calibration Vocabulary: Process-to-Palate

  1. The “Phosphoric” Profile (Success Indicators)
  • Mill Term: Metabolic Stability.
  • Lab Term: Effervescent, Vibrant, Electric.
  • The Sensation: A “buzzing” or “tingling” on the tip and sides of the tongue, similar to the sensation of sparkling water.
  • The Goal: This is achieved by hitting the pH 4.5 target exactly at the 15-18 hour mark.
  1. The “Amino” Profile (Success Indicators)
  • Mill Term: Submerged Hydrolysis.
  • Lab Term: Malty, Toffee, Savory-Sweet, Structured.
  • The Sensation: A weight on the back of the palate and a sweetness that lingers for minutes rather than seconds.
  • The Goal: This is the result of the 33-hour soak. If the cup is “thin,” the soak was too short.
    Troubleshooting the “Red Flags”
    When the lab detects these “Off-Notes,” the Mill Manager must adjust the following variables:
    | What the Lab Tastes | The Technical Defect | The Mill Adjustment |
    |—|—|—|
    | “Phenolic / Medicinal” | CGAs degraded by high heat in the dry tank. | Cool the tank. Use shade or add a splash of cold water. |
    | “Vinegary / Acetic” | pH dropped too low (below 4.0). | Shorten Dry Ferment. Wash the beans 2 hours earlier. |
    | “Onion / Brothy” | Stagnant water during the soak. | Flush Water. Ensure the soak water is fresh and cold. |
    | “Metallic Finish” | Premature drying or “Case Hardening.” | Thin the layers. Increase turning frequency on drying beds. |
    | “Dull / Flat” | Over-washing or short soak. | Extend Soak. Ensure the full 33 hours to build acids. |
    Standard Calibration Exercise
    To align your teams, perform this Triangulation Test once per harvest peak:
  • Cup A (Control): Your standard 15h Dry / 33h Soak lot.
  • Cup B (Variable 1): A lot where you skipped the soak (only dry ferment).
  • Observation: Notice how “thin” and “sharp” this cup is compared to A.
  • Cup C (Variable 2): A lot where you let the dry ferment go to 24+ hours.
  • Observation: Notice the “metallic/phenolic” finish—this is the sound of CGAs breaking down.
    Final Checklist for the Production Manager
  • [ ] BRIX Check: Is the initial sugar above 18°? (If low, adjust time).
  • [ ] pH Probe: Is it calibrated daily? (Crucial for the 4.5 target).
  • [ ] Thermometer: Is the soak water below 20°C? (Essential for “clean” cup).
  • [ ] The Friction Test: Does the parchment “squeak” when rubbed before the soak?
    This concludes your Specialty Fermentation Protocol.