Equipment & Tools
Refractometer
An optical instrument that measures the refractive index of brewed coffee to determine its Total Dissolved Solids (TDS) concentration. TDS is used to calculate extraction yield percentage.
เชิงลึก
Digital coffee refractometers like the VST LAB or Atago PAL-COFFEE measure TDS to two decimal places. By combining TDS with the brew ratio (dose and beverage weight), baristas compute extraction yield—the percentage of soluble material removed from the grounds. The SCA recommends 18–22% extraction at 1.15–1.35% TDS for filter coffee. Refractometers turn subjective taste assessment into an objective, repeatable metric.