Espresso Brew Ratio Calculator
Calculates dose, yield and brew ratio for ristretto through lungo, with the extraction yield that shows why a strong shot and a well-extracted shot are not the same thing.
Espresso Brew Ratio Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Estimated TDS from the ratio is illustrative only. Actual concentration depends on grind, distribution, basket, water and machine behaviour, and can differ by several percentage points.
- The calculator does not model channelling, which is the largest single cause of inconsistent espresso and is invisible to any ratio calculation.
- Shot time windows assume a conventional 9 bar pump profile. Pressure profiling and lever machines legitimately produce different times at the same ratio.
- Basket capacity is not validated. Overdosing a basket restricts headroom and produces slow shots regardless of grind.
In short: The modern reference shot is 18 g in, 36 g out in 25 to 30 seconds — a 1:2 ratio, measured by weight. Ristretto runs 1:1 to 1:1.5 and lungo 1:3 to 1:4. Crucially, strength and extraction are different axes: a ristretto is concentrated yet under-extracted, at roughly 16.5% yield against the 18 to 22% target.
Formula
[('dose', 'Dry ground coffee in the basket, in grams. A modern double is 18 to 20 g.'), ('yield', 'Liquid espresso in the cup, in grams. Weighed, never measured by volume, because crema is foam.'), ('brew ratio', 'Yield divided by dose. 1:2 is the reference; 1:1 to 1:1.5 is ristretto, 1:3 to 1:4 is lungo.'), ('extraction yield', 'The percentage of the dry coffee that dissolved. Target 18 to 22%, and independent of how strong the shot tastes.')]
Worked Example
- Weigh the dose. Grind into the basket and weigh it dry. Consistency here is what makes every later adjustment interpretable.
- Put the cup on a scale. Tare it, start the pump, and stop when the target mass is reached. This is the step that converts espresso from guesswork into a measurement.
- Record the time. Not as a target, but as a diagnostic. Time tells you which way to move the grinder.
- Adjust grind only. Keep dose and ratio fixed and move the grind in single steps until the shot lands in the time window and tastes balanced. Discard the first shot after each grind change.
Consider three shots from the same 18 g dose. A ristretto stopped at 27 g might measure 11% TDS — the strongest of the three in the cup — but its extraction yield is only 16.5%, below the 18 to 22% target, so it is under-extracted. The standard 36 g shot at 10% TDS gives exactly 20%. A 54 g lungo at 8% TDS tastes the weakest of the three, yet extracts at 24% — over-extracted. The strongest shot is the least extracted, and the weakest is the most extracted.
Strengths & Limits Of This Model
Where this engine is strong
- Specifies the shot the way professionals do — two weights and a time — rather than by volume.
- Separates strength from extraction explicitly, which prevents the most common dial-in error.
- Gives roast-specific ratio and temperature guidance instead of one universal recipe.
Where it stops
- Extraction yield is only meaningful with a refractometer, which is an expensive instrument for home use.
- Cannot account for grinder quality, which sets the ceiling on how evenly any shot can extract.
Practical Use Cases
Dialling in a new coffee
Fix the dose and ratio, move only the grind, and the number of variables collapses from four to one.
Reproducing a cafe shot
A cafe that tells you “18 in, 36 out, 28 seconds” has given you a complete specification. Volume-based descriptions give you nothing.
Adapting to roast level
Light roasts generally need longer ratios and hotter water; dark roasts need shorter ratios and cooler water. The ratio is the adjustment, not the machine.
Diagnosing sour shots
Sourness at any strength points to under-extraction. Working in extraction yield rather than perceived strength stops the common mistake of reducing the yield further.
Milk drinks
A ristretto or short normale stands up to milk better because concentration survives dilution, even though the same shot is less fully extracted.
Methodology & Editorial Standards
Shot styles follow current specialty convention: ristretto 1:1 to 1:1.5 at 15 to 22 seconds, short normale 1:1.5 to 1:2, standard double 1:2 at 25 to 30 seconds, extended 1:2.2 to 1:2.5, and lungo 1:3 to 1:4 at 35 to 55 seconds, all as mass ratios of liquid yield to dry dose. The 18 g in, 36 g out, 25 to 30 second reference at 9 bar is the widely used modern baseline. Extraction yield uses the standard identity of TDS percentage multiplied by yield mass divided by dose mass, with the 18 to 22% target band shared with filter brewing. Where no refractometer reading is supplied, TDS is estimated as inversely proportional to the ratio, anchored at 10% for a 1:2 shot, and is presented as an illustration rather than a measurement. Temperature guidance of 88 to 91°C for dark roasts and 94 to 96°C for light roasts reflects standard practice.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Espresso Brew Ratio Calculator — 11 Expert FAQs
11 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
What is the standard espresso brew ratio
1:2 by weight — the modern reference is 18 grams of dry coffee producing 36 grams of liquid espresso in 25 to 30 seconds at around 9 bar. Ristretto is 1:1 to 1:1.5, a short normale 1:1.5 to 1:2, an extended shot 1:2.2 to 1:2.5, and lungo 1:3 to 1:4. All of these are mass ratios, measured with a scale under the cup.
How many grams should a double shot of espresso be
About 36 grams of liquid from an 18 gram dose, at the standard 1:2 ratio. Basket sizes vary — many modern doubles take 18 to 20 g and triples take 21 to 22 — so match the dose to the basket and then apply the ratio. The important point is that 36 grams is a weight, not the 60 millilitres often quoted for a double.
Is a ristretto stronger or weaker than a normal espresso
Stronger in concentration but less extracted. A ristretto stops the shot early, so the liquid carries a higher percentage of dissolved solids — perhaps 11 to 12% against 9 to 10% for a standard shot. But because less total coffee has dissolved, its extraction yield is lower, often around 16 to 17% against the 18 to 22% target. It is simultaneously the strongest and the least extracted of the common shot styles.
What is the difference between strength and extraction in espresso
Strength is the concentration of dissolved coffee in the liquid, measured as TDS. Extraction is the proportion of the dry grounds that dissolved, measured as extraction yield. They move independently: a ristretto is strong and under-extracted, a lungo is weak and over-extracted. Assuming a strong shot must be over-extracted is the most common analytical error in home espresso, and it sends people in exactly the wrong direction.
Why should I weigh espresso instead of measuring volume
Because crema is foam, and its volume is wildly variable. The same 36 grams of espresso can occupy anywhere from roughly 31 to 42 millilitres depending on how fresh the coffee is, how finely it was ground and how the machine releases pressure. Portafilter spout marks and shot-glass lines therefore measure gas as much as coffee, and two shots that look identical can differ by a third in actual mass.
How long should an espresso shot take
25 to 30 seconds for a standard 1:2 double, 15 to 22 for a ristretto and 35 to 55 for a lungo. But time is a result, not a target. It tells you whether the grind is right for the dose and ratio you have chosen. Chasing a specific time by changing the yield instead of the grind simply produces a differently proportioned drink at the same flow rate.
Should I change the ratio for light or dark roasts
Yes. Light roasts are dense and hold their solubles tightly, so they generally want a longer ratio of 1:2.5 to 1:3 and hotter water at 94 to 96°C to extract fully. Dark roasts are brittle and highly soluble, extracting quickly and turning bitter, so they suit a shorter 1:1.5 to 1:1.8 ratio at a cooler 88 to 91°C. Pulling a light roast at a dark-roast ratio is a common cause of persistent sourness.
How do I dial in espresso properly
Fix the dose, fix the target ratio, and change only the grind. Weigh the dose, weigh the shot, note the time, then adjust the grinder one step and repeat. Discard the first shot after any grind change, since stale grounds sit in the burr chamber. Once the shot lands in its time window, judge by taste: sour means grind finer, bitter means grind coarser.
What extraction yield should espresso have
18 to 22% is the conventional target, the same band used for filter coffee, though espresso reaches it at a far higher concentration of 7 to 12% TDS against roughly 1.3% for filter. Measuring it requires a refractometer. Without one, the ratio and time give a reasonable proxy, and taste remains the practical arbiter.
Why is my espresso sour
Almost always under-extraction. Sourness means the water has not dissolved enough of the coffee, so grind finer, raise the temperature, or extend the ratio slightly. It is important not to respond by pulling a shorter shot: that increases the concentration and makes the drink taste stronger, but it lowers extraction further and the sourness gets worse. Light roasts pulled at short ratios are the most frequent culprit.
Does pre-infusion make a difference
On machines that offer it, yes. A few seconds at 2 to 4 bar wets the puck evenly before full pressure arrives, which reduces channelling — the formation of low-resistance paths where water rushes through and extracts unevenly. The effect is most noticeable with light roasts and finer grinds, and it typically allows a finer grind than would otherwise be workable.