What is TDS and extraction yield?

TDS is how ‘strong’ the coffee liquid is; extraction yield is how much of the coffee grounds dissolved into the cup.

The Brewing Control approach comes from measuring ‘soluble solids in beverage coffee’ to predict balance.

- TDS (total dissolved solids) is the percentage of dissolved material in the brewed coffee, often estimated using a refractometer.

Extraction yield (percent extraction) represents the fraction of the dry grounds extracted into the beverage.

The classic ‘ideal’ filter region is commonly taught around ~1.15–1.35% TDS and ~18–22% extraction yield, shown on the SCA Brewing Control Chart.