Espresso Extraction Calculator
Dialing in espresso requires understanding three related measurements: brew ratio (dose to yield), TDS (dissolved solids in the cup), and extraction yield (what percentage of the coffee's soluble compounds ended up in the shot). The Specialty Coffee Association (SCA) publishes target ranges for all three. This calculator takes your dose (dry coffee weight in grams) and yield (liquid espresso weight in grams), calculates the brew ratio, estimates TDS using a simplified empirical model based on industry norms, and calculates extraction yield. If you have a refractometer, enter your actual measured TDS for a more accurate extraction yield. Use this tool after every shot to track what changes produce better or worse results.
Espresso extraction formulas
Brew ratio = yield (g) / dose (g)
Estimated TDS (%) = 11.5 / brew_ratio (simplified empirical model)
Extraction yield (%) = (TDS / 100) * yield / dose * 100
SCA target: TDS 8-12%, Extraction yield 18-22%
Dialing-in guide
- If extraction yield is below 18% (under-extracted): grind finer, increase brew temperature, or increase dose slightly.
- If extraction yield is above 22% (over-extracted): grind coarser, reduce brew temperature, or reduce yield.
- For a balanced espresso, aim for a 1:2 to 1:2.5 brew ratio in 25-30 seconds at 9 bar.
- Weigh both dose and yield with a precision scale (0.1 g resolution) for consistent tracking.
- Change only one variable at a time: grind size, dose, yield, or temperature. Never change two at once.
Espresso extraction: frequently asked questions
What is brew ratio for espresso?
Brew ratio is the ratio of dry coffee (dose) to liquid espresso yield by weight. A 1:2 ratio (e.g. 18 g coffee in, 36 g espresso out) is a standard double espresso. Ristretto is around 1:1 to 1:1.5. Lungo is 1:3 or more. Brew ratio is the most controllable variable in espresso.
What is TDS in espresso?
TDS (Total Dissolved Solids) is the percentage of the espresso that is dissolved coffee. A well-extracted espresso typically reads 8-12% TDS. You measure TDS with a refractometer. Higher TDS means more intense, concentrated espresso.
What is extraction yield?
Extraction yield is the percentage of the coffee grounds that ended up dissolved in the espresso. The Specialty Coffee Association (SCA) targets 18-22% extraction yield for espresso. Under 18% is under-extracted (sour, thin); over 22% is over-extracted (bitter, dry).
How do I calculate extraction yield from TDS?
Extraction yield (%) = (TDS% * beverage_weight_g) / dose_g. To measure TDS, use a refractometer after diluting the espresso. Without a refractometer, this calculator estimates TDS from the brew ratio using a simplified model.
What brew ratio should I start with?
Start with a 1:2 ratio (18 g in, 36 g out) and a 25-30 second brew time at 9 bar pressure. Adjust grind size to hit the target yield in time. If it pulls too fast (under 20 seconds), grind finer. Too slow (over 35 seconds), grind coarser.
Official sources
- Specialty Coffee Association: SCA Coffee Standards.
- USDA Agricultural Research Service: Food Chemistry Research Publications.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.