Espresso Extraction Calculator
Dose + yield + shot time → brew ratio, flow rate, and channeling flag.
Mass of dry ground coffee in the portafilter basket
Mass of liquid espresso out; weigh in the cup (mL ≈ g for espresso)
From first drip to end of pour; start the timer when the pump starts
Get Your Result
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How to Use This Calculator
Weigh Your Dose
Enter the mass of dry ground coffee you loaded into the portafilter basket. 18 g is the modern specialty double-basket starting point: the SCA competition baseline.
Weigh Your Yield
Place a scale under the cup and weigh the liquid espresso output. Stop the shot when you hit your target or when the yield looks right. mL and g are treated as equivalent here (espresso density ≈ 1.05 g/mL; the error is under 5%).
Record Shot Time
Start the timer when the pump starts: not when espresso first appears. Stop when you stop the pump. 28 seconds is the midpoint of the modern specialty 25–35 s window.
What the Numbers Tell You
Three inputs go in: dose, yield, shot time: and the math is simple division. None of those numbers captures distribution or pressure. A 1:2 ratio in 28 seconds through a channeled puck produces a cup that tastes like wet cardboard on one side and overcooked sugar on the other. The calculator diagnoses; taste is the verdict.
The brew ratio is the most actionable number. 1:2 (18 g in, 36 g out) is the modern specialty baseline: where most competition baristas start when calibrating a new coffee. Ristretto (1:1 to 1:1.5): concentrated, sweet, heavy body. Lungo (1:3+): more bitterness, higher extraction, lower TDS. Adjusting the ratio changes what you taste; adjusting grind changes howyou get there. Modern café and competition practice is 14–22 g in, 25–50 g out, 25–35 seconds: well past the SCA’s older 7–12 g standard.
Flow Rate Reference
Informational ranges only: not targets. Flow rate varies through a shot.
| Flow Rate | Typical Interpretation |
|---|---|
| < 1.0 g/s | Slow: may indicate over-resistance (very fine grind, heavy dose, puck issues) |
| 1.0–1.5 g/s | Moderate-slow: common for ristrettos |
| 1.5–2.5 g/s | Typical for modern specialty espresso |
| > 2.5 g/s | Fast: may indicate channeling or coarse grind |
Glossary
- Dose:
- Mass of dry ground coffee in the portafilter basket.
- Yield:
- Mass of liquid espresso produced; also called beverage weight out.
- Brew Ratio:
- Yield ÷ dose, expressed as 1:N (espresso convention: yield is always the larger number).
- Flow Rate:
- Mean rate of espresso extraction in grams per second (yield ÷ shot time).
- Channeling:
- Uneven water flow through the puck, causing partial under- and over-extraction simultaneously.
- Ristretto:
- Short espresso shot with ratio typically below 1:1.5; concentrated and sweet.
- Lungo:
- Long espresso shot with ratio typically above 1:2.5; more extraction, lower TDS.
Frequently Asked Questions
What is espresso brew ratio?
Brew ratio for espresso is yield (liquid out) divided by dose (coffee in), expressed as 1:N. An 18 g dose producing 36 g of espresso is a 1:2 ratio. This is the modern specialty convention: the higher number is always the yield. It differs from filter coffee convention, where ratio usually describes water to coffee.
What is the standard espresso ratio?
1:2 is the specialty baseline: the starting point most competition baristas use when calibrating a new coffee. Ristretto is typically 1:1 to 1:1.5. Lungo runs 1:2.5 to 1:3. Anything above 1:3 is outside the espresso range.
Should I weigh yield in mL or grams?
Grams are more precise. Espresso density is roughly 1.05 g/mL, so volumetric measurement introduces a small error. This calculator accepts either unit and treats them as equivalent: the difference is less than 5% at typical espresso densities.
What does flow rate tell me?
Flow rate is mean yield divided by time: it's an average, not a real-time measurement. Espresso extraction isn't constant: pre-infusion, compression, and puck depletion all change the flow rate during the shot. Use flow rate as a corroborating signal. 1.5–2.0 g/s is typical for a well-pulled modern double; under 1.0 g/s suggests resistance (fine grind, heavy dose, channeling); above 2.5 g/s suggests bypass or coarse grind.
What is channeling?
Channeling happens when water finds a low-resistance path through the puck and bypasses a portion of the coffee. You get fast extraction from the channel and poor extraction everywhere else. It often shows up as a fast shot with higher-than-expected yield. Distribution, tamping level, and basket prep are the first things to check when a channeling flag appears.
Why is my shot flagged even though it tastes fine?
The flags are rule-based diagnostics, not verdicts. A shot at 18 seconds might taste good if you're using a pressurized portafilter or a specific recipe. The flags tell you to check: they don't tell you the shot is wrong. Taste is always the final judge.
What's the difference between ristretto and lungo?
Ristretto is a short espresso: less yield relative to dose, typically below 1:1.5. It's more concentrated, sweeter, with heavier body and lower volume. Lungo is a long espresso: higher yield, more bitterness, lower TDS, more extraction. The ratio changes what you taste; the grind changes how you get there.
Does this calculator apply to espresso on home machines?
Yes. The formula is the same regardless of machine. Dose, yield, and time apply to any pump espresso setup: whether it's a commercial La Marzocco or a home Breville. The ratio bands are calibrated for specialty espresso practice, which skews modern compared to older Italian standards.