Turn a TDS reading from your refractometer into an extraction yield percentage — the industry standard measure of how much of the coffee has dissolved into the cup.
Extraction yield is the mass of coffee that has dissolved into the beverage, divided by the mass of dry coffee used, expressed as a percentage. The formula is:
EY (%) = (TDS × beverage weight) ÷ dose × 100
For espresso, some baristas apply a small correction because retained water in the puck (~2× dose) is not part of the beverage. This tool uses the standard beverage-weight formula, which is accurate for both filter and espresso when yield is weighed at the cup.
SCA target ranges: filter 18–22% EY at 1.15–1.45% TDS, espresso 18–22% EY at 7–12% TDS.
Yes — this tool depends on a TDS measurement. Palate-based dialling in is fine without one; the refractometer just makes iteration faster.
1.30–1.40% TDS at 20–21% EY is a widely-loved specialty range.
Very long shots (1:3+) and very fine grinds push extraction up. Try shortening the ratio or coarsening slightly.
Refractometer readings drift if the sample is hot or foamy. Cool the sample and eliminate crema before measuring.