Espresso reference charts
The numbers worth having in front of you while the machine is warming up. Every chart states where its figures come from, and says plainly which of them are physical facts and which are conventions the specialty coffee world happens to agree on.
Compiled from published manufacturer specifications and published barista guidance.
- Brew Ratio Chart: Espresso and Filter Dose to YieldComplete brew ratio chart for espresso and filter coffee: ristretto 1:1, normale 1:2, lungo 1:3 and filter 1:15 to 1:17, with a... Open →
- Coffee Roast Level Chart: Cracks, Agtron and Brew TemperatureCoffee roast level chart from light to dark: first and second crack temperatures, approximate Agtron bands, surface oil, espresso... Open →
- Espresso Extraction Troubleshooting Chart: Symptom, Cause, FixEspresso troubleshooting chart: sour, bitter, gushing, choking, no crema, uneven shots and channelling, with the single change to... Open →
- Espresso Machine Boiler Types Chart: Warm-Up, Steam and PriceEspresso machine boiler types compared: single boiler, dual boiler, heat exchanger, thermoblock, thermocoil, thermojet and... Open →
- Grind Size Chart: Microns by Brew MethodCoffee grind size chart in microns: espresso 200 to 400, moka 300 to 500, pourover 400 to 800, drip 600 to 900, French press 900 to... Open →
- Milk Temperature Chart: Steaming and Serving TargetsMilk steaming temperature chart in C and F: stretch below 38 C, serve at 55 to 65 C, scalded above 70 C, plus foam depth and... Open →
- Portafilter Basket Size Chart: 49 mm to 58 mmPortafilter size chart from 49 mm to 58 mm: which espresso machines use each diameter, single and double dose ranges, and which... Open →
- Water Hardness Chart for Espresso: ppm, Grains and Descale IntervalsWater hardness chart for espresso machines: ppm as CaCO3, grains per gallon, soft to very hard bands, what each does to a boiler... Open →
What is the headline number on each chart?
If you read nothing else, read this table. Each row is the one figure that chart exists to establish, and between them they cover most of what goes wrong at a home machine.
| Chart | The number | What it means |
|---|---|---|
| Brew ratio chart | 1:2 | Espresso normale: 18 g in, 36 g out |
| Grind size chart | 200 to 400 um | The espresso band, finer than table salt |
| Extraction troubleshooting | 18 to 22% | The conventional extraction yield window |
| Water hardness chart | 50 to 100 ppm | Target total hardness as CaCO3 |
| Milk temperature chart | 55 to 65 C | Texture here, scalded above 70 C |
| Roast level chart | 7 to 21 days | The window espresso wants off roast |
| Basket size chart | 58 mm | The commercial standard the market is built around |
| Boiler types chart | 9 bar | Conventional brew pressure at the puck |
Which of these numbers are facts and which are conventions?
Worth separating, because the two behave differently when you break them. The conversion figures are facts: 1 grain per gallon is 17.1 ppm, a brew ratio is arithmetic, and milk proteins denature at a temperature that does not care what you think about it. Break those and you get a wrong answer or scalded milk.
The target windows are conventions. The 18 to 22 percent extraction yield window, the 9 bar pressure standard and the 1:2 espresso ratio are all agreements about what most people find tastes good, not laws. Plenty of excellent coffee is pulled at 6 bar, or at 1:3, or at 24 percent, and lever machines break the pressure convention by design. Treat them as the place to start rather than the place to end, which is exactly how the dial-in guide uses them.
Which chart fixes which problem?
- The shot tastes sour or bitter. Start at the extraction troubleshooting chart. Sour and thin means under-extracted, so grind finer. Bitter and drying means over-extracted, so grind coarser. Change one variable at a time.
- The grinder will not go fine enough. The grind size chart shows where espresso sits against every other method, and why a grinder built for filter often cannot reach it.
- The machine is slowing down or the steam is weak. Almost always scale. Check the water hardness chart against your reading from the hardness calculator.
- The milk keeps coming out bubbly. The milk temperature chart gives the window, and the milk guide gives the technique.
- You are shopping and the spec sheets disagree. The boiler types chart and the basket size chart between them decide most of a shortlist, and the machine index lists both specs for every model on the site.
How should you use a chart while you are actually brewing?
Pick one number to hold and one to change. Hold the dose at 18 g and the yield at 36 g, and change only the grind until the shot lands in 25 to 30 seconds. Once time is stable, taste, and move temperature or ratio a single step. Two variables moved at once produce a result you cannot attribute, which is how people end up three weeks into a bag with no idea what works.
The brew ratio calculator and the dose and yield calculator do the arithmetic while you are standing at the machine, and the complete builds list the scale and timer that make any of it measurable in the first place.