calculators.coffee by Timberline Coffee School

Extraction Yield Calculator

Dose + brew weight + TDS → EY%, with SCA 18–22% target band diagnosis.

Mass of dry ground coffee you started with

Mass of the brewed liquid in your cup (weigh it)

Refractometer reading: use a coffee-calibrated refractometer

Last updated

How to Use This Calculator

  1. Weigh Your Dose

    Enter the dry ground coffee mass in grams: the amount you started with before brewing. 15 g is the default (a standard V60 or AeroPress dose).

  2. Weigh the Brewed Liquid

    After brewing, weigh the liquid in your cup: not the brew water you used. For pour-over, weigh the server after removing the dripper. Default is 240 g (a 1:16 ratio at 15 g dose).

  3. Enter Your Refractometer Reading

    Take a TDS reading on your cooled sample with a coffee-calibrated refractometer. Enter the % value. Default 1.30% is the SCA midpoint for filter coffee.

What Extraction Yield Tells You

Extraction yield is the percentage of dry coffee mass that dissolved into the brewed liquid: not how it tasted. An 18% extraction and a 22% can both taste good; a 16% and a 26% rarely do. The SCA’s 18–22% target is a practical window for filter methods, not a quality guarantee. I’ve had excellent cups at 17.5% and flat ones at exactly 21%.

The number earns its place when you pair it with taste. Sour cup, EY reads 16%? Under-extracted: grind finer or extend contact time. Bitter at 25%? Over-extracted: go coarser. EY confirms what your palate is telling you and gives you something to track across grind adjustments.

When to Measure Extraction Yield

  • Dialling in a new coffee. EY gives you a repeatable number to track across grind adjustments, so you can move methodically instead of guessing.
  • Diagnosing a problem cup.If it tastes wrong and you don’t know why, TDS + EY tells you whether the issue is strength (TDS) or extraction (EY): and points you toward the right fix.
  • Comparing brewing methods.The same coffee brewed as pour-over and AeroPress at the same EY will taste different, which isolates the method’s contribution from the extraction variable.
  • Batch brew calibration. Commercial and batch brew systems benefit from regular EY spot-checks because grinder burr wear and basket channelling drift extraction over time.

Glossary

Extraction yield:
Percentage of dry coffee mass that dissolved into the brewed liquid.
TDS (Total Dissolved Solids):
Concentration of dissolved coffee solids in the liquid, measured by refractometer as a percentage.
Brew Weight:
The mass of the brewed liquid output (not the brew water you poured in).
Dose:
Mass of dry ground coffee used for brewing.
Filter Coffee Brew Standard:
SCA's recommended brewing parameters: 18–22% extraction yield, 1.15–1.35% TDS for filter coffee.
VST Method:
Protocol for measuring coffee TDS by refractometer and calculating extraction yield. The industry standard adopted by the SCA.

Frequently Asked Questions

What is extraction yield in coffee?

Extraction yield is the percentage of the dry coffee mass that dissolved into the brewed liquid. A 20% EY from a 15 g dose means 3 g of coffee solids ended up in your cup. The SCA's target range is 18–22% for filter methods.

What do I need to measure extraction yield?

A scale and a coffee-calibrated refractometer. The scale measures dose and brew weight. The refractometer measures TDS (the concentration of dissolved solids in the liquid).

A coffee-calibrated refractometer reads directly in TDS% for coffee. A standard Brix refractometer requires a conversion factor.

Why use brew weight instead of brew water weight?

The refractometer reads concentration in the final cup, not the water you poured. Coffee grounds absorb roughly twice their weight in water during brewing. Using brew weight (liquid out) matches the VST protocol and gives the correct result.

My extraction yield is in the SCA target but the coffee tastes off. Why?

EY tells you how much dissolved, not what dissolved. Roast level, grind distribution, water chemistry, and brew method all affect which compounds extract at which yield levels. An 18% EY from a light roast and an 18% EY from a dark roast taste very different. Use EY as a diagnostic baseline alongside taste.

What is the filter coffee brew standard?

The Specialty Coffee Association's recommended parameters for filter coffee: 18–22% extraction yield and 1.15–1.35% TDS. The target is a practical window based on sensory research: not a guarantee of quality for every coffee or palate.

Can I use a Brix refractometer instead of a coffee refractometer?

You can, but Brix scales are calibrated for sucrose, not coffee solids. The readings will be off by a correction factor. Coffee-calibrated refractometers apply that correction internally. If you're using a Brix unit, look up the coffee-specific conversion for your model.

Does extraction yield apply to espresso?

Yes, the VST formula works for espresso too: but the TDS and brew weight values will be very different. Espresso typically runs 8–12% TDS and 30–50 g brew weight, yielding EYs in a similar 18–22% range when dialled in correctly.

Timberline Coffee School

Trent built this calculator. He also runs Timberline Coffee School, where baristas and roasters train through SCA-accredited programs covering espresso, brew method, and sensory skills.

Related Calculators