Refractometer use and calibration

Refractometer Basics

• Purpose:

• Measures TDS (% of dissolved solids in brewed coffee).

• Used to calculate extraction yield when combined with brew ratio and yield.

• Proper Use:

• Filter out oils and fines from coffee sample (paper filter or syringe filter) before measurement.

• Place a few drops on the refractometer lens or sensor.

• Record TDS reading once stabilized.

• Calibration:

• Regularly calibrate with distilled water (should read 0.00% TDS).

• Some refractometers include calibration solutions at known TDS values.

• Recalibrate frequently to avoid drift.

• Practical Workflow:

• Brew coffee, measure TDS, and calculate extraction yield.

• Compare against target ranges (18–22% EY, 1.2–1.5% TDS for filter; 8–12% TDS for espresso).

• Best Practices:

• Clean prism or sensor thoroughly after each use to avoid contamination.

• Take multiple measurements for accuracy.

• Use readings alongside sensory evaluation for holistic quality control.

Summary

A refractometer is a vital QC tool that allows baristas and roasters to measure extraction with precision. Proper calibration and use ensure consistent, reproducible brews aligned with sensory goals.

• Tags:
• Best Practices
• Quality Control
• Extraction Yield
• Brewed Coffee
• Brew Ratio
• Sensory Evaluation
• Oils Fines
• Ensure Consistent
• Dissolved Solids
• Paper Filter
• Baristas Roasters
• Measure Tds
• Avoid Contamination
• Ey Tds
• Practical Workflow