How much coffee do you use for a shot of espresso?

18 g to 20 g of ground coffee in a standard double basket, producing about 36 g to 40 g of liquid espresso. That is a 1:2 ratio by weight and it is the recipe almost everyone starts from. Weigh both the dose and the yield rather than judging by eye, because a dose that drifts by a gram or two changes the shot more than most beginners expect.

How long should an espresso shot take?

Roughly 25 to 30 seconds from when the pump starts, to reach a yield of about twice the dose. Treat the time as a reading rather than a target: stop the shot on weight, then look at how long it took. If 18 g gave you 36 g in 20 seconds the grind is too coarse; if it took 45 seconds it is too fine. Adjust the grind in small steps, since one notch can move a shot by ten seconds.

Why is my espresso sour?

Sour, thin espresso is under-extracted: the water passed through the coffee too quickly to dissolve enough of it. Grind finer so the water meets more resistance. If the shot tastes sour and bitter at the same time, the cause is usually channelling rather than grind, meaning water found a fast route through part of the puck. Fix that by levelling the grounds and tamping flat before changing the grinder.

Do you need a special grinder for espresso?

Yes, in practice. Espresso needs a much finer and more consistent grind than drip coffee, and it needs fine adjustment between settings, which blade grinders and most cheap burr grinders cannot do. Pre-ground supermarket coffee is ground for drip and will not produce good espresso in any machine. If you have to choose between spending on the machine or the grinder, spend on the grinder.

What pressure should an espresso machine be?

About 9 bar at the coffee. Machines advertised as 15 bar or 20 bar are quoting the pump's maximum rating, not the pressure used to brew, and the machine regulates down internally. A higher number on the box does not mean better espresso, and it is not a useful way to compare machines.

How to Make Espresso: A Beginner's Walkthrough

What you actually need

The recipe almost everyone starts with: 18 g of coffee in, 36 g of espresso out, in 25 to 30 seconds, then change the grind and only the grind until the shot lands there. Sour and fast means grind finer. Bitter and slow means grind coarser.

An espresso machine that can hold around 200 F and push water at roughly 9 bar. A grinder that adjusts finely enough to change a shot. Fresh beans, roasted within the last month, and a scale that reads to 0.1 g.

That list is in the wrong order on purpose, because most people buy it in the wrong order. The grinder moves shot quality more than the machine does at any price under about $1,500. If your budget will not stretch to both, shrink the machine budget first. Pre-ground coffee will not make good espresso in any machine, because it is ground for drip and it went stale within days of the bag opening.

You do not need a bottomless portafilter, a distribution tool or a puck screen to start. They are refinements to a technique you have not built yet.

Grinders drop coffee in clumps, and the gaps between them are where water will go first. Levelling the bed before you tamp costs a few seconds and removes the most common cause of an uneven shot.

The five steps

1. DOSE. Grind fresh into the basket and weigh it. A standard double basket wants 18 g to 20 g. Use the same number every time, because if the dose moves you cannot tell whether a change came from the grind or the amount.

2. DISTRIBUTE. Level the grounds before you tamp. Tap the side of the portafilter, or run a cocktail stick through the bed in a few passes. Grinders drop coffee in clumps and a lumpy bed lets water carve a channel through the weakest point.

3. TAMP. Press straight down until the bed stops compressing. Level matters far more than force: a tilted tamp sends water down the shallow side. Do not polish, twist or tamp twice.

4. LOCK IN AND BREW IMMEDIATELY. Grounds sitting in a hot group head start cooking. Lock the portafilter in and press the button.

5. STOP ON WEIGHT, NOT TIME. Put the cup on the scale and stop when you have the yield you want. Time is a reading you take, not a target you chase.

A level bed makes water work through the whole puck. Tilt it and the water races down the shallow side, so that part over-extracts and turns bitter while the deep side stays sour. That is why a shot can taste sour and bitter at once, and why levelling matters more than how hard you press.

The numbers worth knowing

The starting recipe almost everyone uses is 1:2 in about 25 to 30 seconds. So 18 g of coffee in, 36 g of liquid espresso out, timed from when the pump starts.

Those three numbers are linked, and the grind is what ties them together. If 18 g gives you 36 g in 20 seconds, the grind is too coarse and water is running through too easily. If it takes 45 seconds, the grind is too fine. Change the grind, not the dose, and change it in small steps: espresso grind settings are unforgivingly sensitive, and one notch can move a shot by ten seconds.

Brew temperature sits around 200 F for most coffees, and 9 bar is the pressure the machine is aiming for even when the box says 15 or 20 bar. Those higher numbers are pump ratings, not brew pressure.

Dose and shot size also change how much caffeine ends up in the cup: our caffeine study puts 124 lab-measured single espressos, 14 UK retail filter coffees, USDA's reference figures and Starbucks' declared numbers on one chart.

The recipe almost everyone starts from. These three numbers are linked, and the grind ties them together: if 36 g arrives in 20 seconds the grind is too coarse, and if it takes 45 seconds it is too fine. Change the grind, not the dose.

Steaming milk, briefly

Two things happen when you steam milk and they happen in order. First you add air, then you heat and texture it. Get them the wrong way round and you get bubbles instead of foam.

Purge the wand, put the tip just under the surface and open the steam. You want a quiet hissing for two or three seconds while the volume rises slightly. Then sink the tip deeper and let the milk spin until the jug is too hot to hold comfortably, somewhere around 140 F. Turn the steam off, wipe the wand and purge it again straight away.

Milk that has been overheated cannot be rescued and tastes scalded, so stop earlier than feels right while you are learning. This is a skill with its own depth and we will give it a guide of its own.

Air first, then texture, and never the other way round. A few seconds of quiet hissing near the surface, then sink the tip and let it spin until the jug is too hot to hold comfortably. Milk that has been overheated cannot be rescued, so stop earlier than feels right while you are learning.

Reading a shot that went wrong

Sour, thin, and it ran fast. The water got through too easily, so the coffee is under-extracted. Grind finer.

Bitter, dry, and it ran slowly or dripped. The water spent too long in the bed, so it is over-extracted. Grind coarser.

Sour AND bitter at once usually means channelling: water found a fast route through part of the puck and over-extracted the rest. That is a distribution and tamping problem rather than a grind problem, so level the bed properly before you touch the grinder.

Fast the first time and slow the next with nothing changed points at the dose moving, the beans being stale, or the grinder retaining coffee between shots.

Flow tells you which way to move the grinder before you taste anything. Fast and pale means grind finer; a slow drip means grind coarser. Sour and bitter together is neither: that is channelling, so level the bed before touching the grind.

What to expect from yourself

The first week is dialling in, not drinking well. A new bag of coffee needs its own dial-in, and beans keep moving for a few days after roasting, so a recipe that worked on Monday can want a small change by Thursday.

Weigh everything while you are learning. Almost every problem people bring to a forum turns out to be an unmeasured dose or an unweighed yield, and both are free to fix.