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Choose the closest drink style or your own control box.
Changing the unit converts the displayed quantity without changing the dose.
Weigh the mixed beverage whose refractometer sample you measured.
Measure a mixed, cooled, and suitably filtered sample.
This meaning-changing factor stays beside the Brix reading.
×
Leave unrecorded for measurement-only guidance.
Center is the neutral comparison point.
Added to the converted reading before the mass balance.
points
Bypass must be less than the finished beverage mass.
This produces a clearly labelled scenario, not a direct measurement.
Two decimal places is the neutral presentation default.
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Dial-in guide

Extraction

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Strength

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Next brew

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Measurement checks

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Two brews can have the same strength and taste different because strength describes the beverage, while extraction yield describes how much soluble material left the dry coffee. Total dissolved solids (TDS) measures dissolved material as a percentage of beverage mass. Extraction yield compares that dissolved-solids mass with the original dry dose.

Strength or TDS
How concentrated the measured beverage is.
Extraction yield
The percentage of the dry coffee dose represented by dissolved solids in the collected beverage.
Beverage ratio
Collected beverage mass divided by dry coffee dose, such as 320 g ÷ 20 g = 16.

These measurements are most useful for repeatable dial-in work. Dose and beverage mass should be weighed, the beverage mixed before sampling, and the refractometer sample cooled and filtered as recommended for the meter. A TDS reading from the top of an unmixed brew or a Brix value treated as TDS can move the calculated yield enough to suggest the wrong grind change.

Target boxes are reference ranges, not taste verdicts. Grind, contact time, temperature, agitation, water chemistry, roast, and grinder distribution all affect flavor and extraction. Use the measured position to decide which variable to test next, then change one variable and repeat the measurement. A number inside a target range does not override a defect that is obvious and repeatable in the cup.

How to Use This Tool:

Record one brew with measurements from the same mixed beverage sample.

  1. Choose the Brew profile, then enter dry coffee dose and collected beverage mass in grams or ounces.
  2. Enter the refractometer reading and select TDS or Brix. For Brix, use the conversion factor appropriate to the meter and coffee workflow.
  3. Choose a target aim and optionally record a taste cue. Use a documented reading correction only when a meter check supports it.
  4. Add bypass water only when it was already mixed into the weighed beverage. Add retained liquid only as an estimate of liquid left with the grounds.
  5. Read extraction yield and strength together, review any meter or range warning, and change one brewing variable before measuring again.

Interpreting Results:

Extraction status and strength status are independent. Low extraction with high strength usually calls for improving contact or flow rather than adding more coffee. High extraction with low strength may call for a tighter beverage ratio while reducing the extraction pressure. When both measurements are inside the selected ranges, repeatability and taste are better reasons to change the recipe than a small difference from the chosen aim.

Lower and upper target limits are inclusive. A filter extraction yield of exactly 18% or 22%, for example, is In target. Values below the lower limit are Below target; values above the upper limit are Above target. Recheck units, meter scale, sample preparation, and dose before acting on an extreme result.

Technical Details:

Extraction yield follows a collected-beverage mass balance. The method first converts the refractometer reading to effective TDS, finds the dissolved-solids mass in the collected beverage, and divides those solids by the dry dose. Grams and ounces are converted to grams before the calculation.

Formula Core:

The core equations preserve full precision; the selected one-, two-, or three-decimal display setting changes presentation only.

T =Rf+c S =MT100 EY =SD×100 EYretained =S+MrT/100D×100 Tpre-bypass =SM-Mb×100

R is the meter reading; f is 1 for TDS or the entered Brix-to-TDS factor for Brix; c is the reading correction in percentage points; T is effective TDS percent; M is collected beverage mass; S is dissolved-solids mass; D is dry dose; Mr is retained-liquid mass; and Mb is bypass-water mass already included in the beverage.

Rule Core:

Brew profileExtraction yieldStrength
Filter / pour-over18% to 22%1.15% to 1.45% TDS
Immersion / AeroPress18% to 22%1.20% to 1.55% TDS
Espresso18% to 22%8% to 12% TDS
Concentrate / moka18% to 24%3% to 5% TDS

The lower, center, and upper aim choices use 25%, 50%, and 75% of the distance across each selected range. Classification includes both endpoints and uses only a tiny floating-point tolerance around them. Custom extraction limits must be from 0% to 40%, custom TDS limits from 0% to 35%, and each upper limit must be greater than its lower limit.

For a 20 g dose, 320 g beverage, and 1.35% TDS, dissolved solids are 4.32 g and extraction yield is 21.6%. The beverage ratio is 16, and the measurement falls inside the default filter ranges of 18% to 22% extraction and 1.15% to 1.45% TDS.

Accuracy Notes:

Measurement quality usually matters more than extra decimal places. Temperature compensation, calibration, filtration, sample mixing, fines, dissolved gases, and an unsuitable Brix factor can all shift the reading.

  • A Brix factor outside 0.70 to 1.00 or a correction larger than 0.5 percentage points triggers a warning, although the accepted input limits are wider.
  • Bypass water must be less than the weighed beverage mass. The pre-bypass result assumes the same dissolved-solids mass before dilution.
  • The retained-liquid result assumes liquid left with the grounds has the same TDS as the collected beverage. It is a rough scenario, especially when retained mass exceeds beverage mass.
  • Extraction yield above 35% triggers an extreme-result warning. Confirm the scale, dose, beverage mass, and sample before changing the brew.

Worked Examples:

Brix converted before extraction

A 1.60 °Bx reading with a 0.85 factor becomes 1.36% TDS. With a 20 g dose and 320 g beverage, that gives 4.352 g dissolved solids and 21.76% extraction yield. Treating 1.60 as TDS instead would overstate extraction.

Espresso strength and yield read together

An 18 g dose, 36 g beverage, and 9.5% TDS produces 3.42 g dissolved solids and 19% extraction yield. Both values sit inside the espresso target box even though the drink is far stronger than filter coffee; the profile determines the useful strength comparison.

References: