The short answer, by basket diameter: a 58mm double takes around 18 grams, with aftermarket precision baskets commonly specified 18-20g or 18-22g. A 54mm Breville double takes roughly 18-22 grams. A 51mm basket takes about 15-18 grams. A single basket of any diameter is roughly half its double. But the number that actually matters is the one specified for your basket — baskets are manufactured to a dose range, and that range is printed on the box or stamped on the rim.
The useful thing to understand is whythe basket decides. People ask this question about their machine — "how much coffee goes in a Bambino" — and that is the wrong frame. The machine sets the diameter and nothing else. Swap the basket and the dose changes, on the same machine, the same day.
Why the basket sets the dose
A basket is a volume, and coffee is a volume.The dose has to fill the basket to a particular depth — enough coffee that the puck, once tamped, sits a few millimetres below the shower screen. Too much and the puck is crushed against the screen when you lock in; too little and there is a void the water pools in instead of flowing evenly through the bed. The basket's diameter and depth together define how many grams achieve that, which is why the number changes with diameter and why a deeper 58mm basket takes more than a shallow one of the same width.
Headspace is the thing you are really setting. The usual target is about 3 to 5mm between the top of the tamped puck and the shower screen. You can check it directly: dose, tamp, lock the portafilter in, then remove it and look at the puck. A faint ring from the screen is fine. A deep circular imprint across the whole surface means you are over-dosed. No mark at all with a visible gap means you have room for more.
Bean density moves the grams, not the volume. This is why a dose that works all month suddenly over-fills when you open a new bag. Darker roasts are less dense than lighter ones, so the same 18 grams occupies more space. If you change roast level and the puck starts imprinting, that is the cause — and the fix is a gram or two less, not a different basket.
Dose by diameter
58mm — the commercial standard.Around 18g in a stock double. Gaggia, Rancilio, Breville's Dual Boiler and most prosumer and commercial machines use this size. Aftermarket precision baskets are commonly specified 18-20g or 18-22g, which gives you headroom to run a bigger dose if you prefer a shorter, more concentrated shot. Singles are typically 7-9g, triples 21g and up.
54mm — the Breville and Sage standard. Roughly 18-22g in a precision double, and that is a genuinely useful range: it is wider than people assume given the smaller diameter, because Breville baskets are comparatively deep. The stock dual-wall pressurized basket is a different matter — see below, because on that basket the dose question is partly moot.
51mm — De'Longhi Dedica, Stilosa, CASABREWS and the budget tier. About 15-18g. These baskets are both narrower and shallower, which is why the number drops. It also means 51mm is the diameter least forgiving of over-dosing: there is simply less headroom to absorb an extra gram.
If you are not sure which diameter you have, measure the inside of the basket rather than the outside of the portafilter body, or look your machine up in portafilter size by brand. Portafilter sizes explained covers why the standards exist and why the measurements never quite match the names.
What to look for in a basket, before you pick a dose
The dose question only becomes meaningful once you are on a basket that extracts properly. Two things matter.
Single wall, not pressurized. Most machines ship with a dual-wall pressurized basket, which has a single tiny outlet hole and manufactures crema through back-pressure rather than through extraction. On that basket, dose precision barely changes the cup, because the restriction is doing the work. The moment you own a real grinder, swap to single wall — pressurized vs unpressurized baskets covers the difference in full.
A stated dose range. Precision baskets from manufacturers like IMS are made to a tolerance and published with a dose range, which is the whole point: you are not guessing, you are reading a specification. Generic baskets often give no figure at all, which leaves you back at eyeballing headspace.
The three baskets below are the ones in our registry that carry published dose ranges, one per diameter — followed by the scale that makes any of this repeatable.
Dose by basket diameter
Ranges below are the published specifications for the exact baskets in our registry, plus the standard stock-basket figures for each diameter. Always prefer the figure printed on your own basket.
| Diameter | Machines | Stock double | Precision basket range | Single |
|---|
| 58mm | Gaggia, Rancilio, Breville Dual Boiler, most prosumer | ~18g | 18-20g or 18-22g | ~7-9g |
| 54mm | Breville and Sage Barista line, Bambino | ~19g | 18-22g | ~8-10g |
| 51mm | De'Longhi Dedica, Stilosa, CASABREWS and similar | ~14-16g | 15-18g | ~7g |
What goes wrong when the dose is off
Over-dosed. The puck is crushed against the shower screen when you lock in, and once wet it swells further. Symptoms: a deep circular screen imprint across the whole puck, a portafilter that is hard to lock in and sometimes hard to remove, and a shot that runs slow and tastes harsh. In the worst case the handle sticks — see how to remove a stuck portafilter. Over-dosing is far more common than under-dosing, because people assume more coffee means a stronger shot.
Under-dosed. Too much headspace means the water pools above the puck instead of meeting it evenly, and the bed can lift and crack under pressure. Symptoms: a shot that runs fast and pale, a wet sloppy puck that will not knock out cleanly, and a thin sour cup. The puck surface often shows a crater where the water broke through.
Right dose, wrong grind. Worth distinguishing, because the symptoms overlap and people change the wrong variable. A correct dose with too coarse a grind also runs fast and sour; a correct dose with too fine a grind also runs slow and bitter. The tell is the puck: a clean, intact puck with a faint screen ring means your dose is right and the grind is the variable to move. A crushed or cratered puck means fix the dose first. Espresso grind size covers which way to turn the dial.
How to find your own number, in five minutes
1. Read the basket. Precision baskets are stamped or boxed with a dose range. If yours has one, start at the middle of it and stop reading here.
2. If there is no figure, use the diameter table above as a starting point: 18g at 58mm, 19g at 54mm, 15g at 51mm.
3. Dose, tamp level, lock in, then take it out and look. You are checking the puck surface for headspace. A faint ring from the screen is correct. A deep imprint across the whole face is over-dosed — drop a gram and repeat. No contact and an obvious gap is under-dosed — add a gram.
4. Write the number down with the basket and the bean. That is your dose until you change one of them.
5. Re-check when you change beans. Especially across roast levels, because density shifts the volume the same grams occupy.
Two notes. Level the bed before tamping or the headspace reading is meaningless — a lopsided puck has no single height. Our best espresso distribution tools page covers that step, and espresso puck prep covers the whole routine. And weigh it — our scale pick above exists for this reason, and how to tamp espresso covers the step that turns the dose into a puck.
Dose, yield and ratio: how the three connect
Dose is coffee in. Yield is liquid espresso out, by weight, not by volume. Ratio is the relationship between them, and it is the number that defines the drink.
A standard double is around 1:2 — 18 grams in, roughly 36 grams out, in about 25 to 30 seconds. Tighter ratios give you a ristretto: shorter, heavier, sweeter, less developed. Wider ratios give you a lungo: longer, thinner, more extracted and usually more bitter. Our ristretto vs lungo guide covers that spectrum, and single vs double shot espresso covers why doubles dominate — a single basket is harder to extract evenly because the bed is so shallow.
The practical consequence for dose: pick a dose that suits your basket, then adjust yield and grind to taste. Do not use dose as your flavour dial. Changing dose changes the bed depth and therefore the resistance, so it moves two variables at once — which is exactly what makes dialing in feel impossible. Fix the dose, then work the grind, as in how to dial in espresso.
