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Coffee Extraction Yield Calculator (SCA Brewing Chart)

Calculate coffee extraction yield and brew strength from dose weight, beverage weight, and a refractometer TDS reading, classified against the SCA's Golden Cup Standard.

Extraction yield
20.25%
Extraction
Ideal
Strength (TDS band)
Ideal (Golden Cup)
Brew ratio
1:15

Where this falls

20.3 falls in the "Ideal" range.

How it works

The Specialty Coffee Association's Brewing Control Chart plots two independent measurements: strength (TDS, the percentage of the brewed coffee's mass that's dissolved coffee solids, read from a refractometer) and extraction yield (the percentage of the dry coffee grounds' own mass that ended up dissolved in the cup). Extraction yield follows from a simple mass balance: the dissolved-solids mass is TDS% × beverage weight, and dividing that by the dry coffee dose gives extraction yield — algebraically, EY% = TDS × beverage weight ÷ dose weight.

The SCA's Golden Cup Standard sets reference bands for both axes: an extraction yield of 18-22% is considered the ideal range (below is under-extracted and tastes sour/thin, above is over-extracted and tastes bitter/harsh), and a TDS of 1.15-1.35% is the ideal strength range for filter coffee — this calculator classifies your numbers against both bands.

Brew ratio (beverage weight ÷ dose weight, shown as 1:X) is reported alongside extraction yield as a genuinely distinct figure — two brews with the same ratio can still land at very different extraction yields depending on grind size, brew time, and water temperature, which is exactly why the chart tracks extraction separately from ratio.

FAQ

Why do I need a refractometer for this?

TDS (total dissolved solids) can't be measured by eye or taste alone — a refractometer reads how brewed coffee bends light compared to plain water, which is proportional to how much is actually dissolved in it. Without one, extraction yield can only be estimated qualitatively from taste, not calculated.

My extraction yield is 'ideal' but the coffee tastes bad — why?

The Golden Cup Standard bands are a starting reference calibrated broadly across roasts and origins, not a guarantee of a good cup — a specific bean, roast level, or personal taste preference can land well outside 18-22% and still taste great to you, or inside the band and taste flat. Use the numbers to diagnose and adjust your brewing consistently, not as an absolute pass/fail.

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