1. Overview & Physics
Light Refraction Science
Refractometers measure refractive index?봦ow much light bends when passing through a coffee sample. Because dissolved organic compounds bend light proportionally, the refractometer calculates the precise TDS (Total Dissolved Solids) value. Using this value, baristas calculate extraction yield to calibrate grind profiles scientifically.
Calibration Routine
Calibrate your refractometer using distilled water before every session. Filter your coffee sample through a syringe filter to remove micro-fines before measuring.
2. Practical Calibrations
Managing this requires measuring indicators in real time. Adjust grind size, water dynamics, and flow parameters incrementally. Change only one variable at a time to ensure clean results and isolate target parameters.
Barista Action Checklist
- Weigh dry grounds dry dose exactly to 0.1g.
- Calibrate water temperature using PID sensors.
- Target correct brew ratios (e.g. 1:15 for filter, 1:2 for espresso).
- Swirl or stir to ensure even saturation during extraction.
- Record extraction time and evaluate flavor notes subjectively.
Frequently Asked Questions
What is TDS in coffee?
TDS (Total Dissolved Solids) measures the percentage of coffee compounds dissolved in the water, indicating brew strength.
How do I calculate extraction yield?
Extraction Yield % = (Brewed Coffee Weight * TDS %) / Dry Coffee Ground Weight. Target a yield between 18% and 22%.
