Dial in
At 1× the shots run in real time, so you can count the seconds with the barista; grinding and tamping are squeezed.
Seed to Swan
Dial in an espresso the way baristas do: grind, dose, tamp, pull, weigh, time and taste, then change one thing. Watch the water soak through the puck, the stream go from dark to pale, and see why a shot tastes sour, sweet or bitter.
At 1× the shots run in real time, so you can count the seconds with the barista; grinding and tamping are squeezed.
Everything behind the animation: the machine, the recipe, the grind, what happens inside the puck, how to read a shot and fix it by taste, a lab to try it yourself, the common mistakes, recipes by roast, cleaning, beans and gear.
An espresso machine does three jobs: it heats water to a steady 90–96 °C, pushes it at about 9 bar through a tight cake of ground coffee, and holds that cake in the portafilter while it does. Calibration only works on a machine that is warm, clean and steady.
Three numbers make an espresso recipe: the dose of ground coffee that goes in, the yield of espresso that comes out (both weighed in grams), and the time it takes. The ratio between dose and yield sets the style; the time tells you whether the grind is right.
Write down your own recipe with everything that matters: the beans, the roast, how much goes in and out, the water, the pressure, the grind and how it tasted. The numbers underneath tell you if it sits where the sources say it should for that roast. Save it, and open it again whenever you dial in the same coffee.
Use a scale that reads 0.1 g, under the portafilter for the dose and under the cup for the yield. Volume misleads: crema is mostly gas, and a fresh or dark coffee makes far more of it than an old or light one at the same weight.
Time from the moment you press the button (preinfusion included), not from the first drop. The first drops come 5–10 s later; if you time from them, aim about 5 s shorter.
The number on the basket (look on its side) is the dose it was made for, an upper limit give or take 1 g: single 7–10 g, double 14–21 g, most often 18 g. Less is fine but leaves a soupy puck; more presses the coffee against the shower screen.
Stop the shot when the cup reaches the yield (a gram or so early: the last drops still come). If you stop by time instead, you lose the one number that tells you the grind is off.
Dark roasts are lighter and puffier, so 18 g of them takes more room; a coarse grind does too. If a coffee overflows the basket at the right grind, use a little less (and keep the ratio) or a bigger basket. Coin test: a coin on the tamped bed, lock in, take out: it should only just leave a mark.
Water finds its way through the gaps between the grains. Smaller grains leave smaller gaps and offer more surface: the water slows down and dissolves more. That is why the grinder is the dial you turn most, and why one setting on it can change a shot by several seconds.
A Sage Smart Grinder Pro (Breville outside Europe), a popular home grinder: steel conical burrs and 60 settings on its screen, 1 the finest, 60 the coarsest. Settings 1–30 are its espresso range and Sage suggests starting at 12; the house blend here lands on 14.
Setting 14 means something only on this grinder. A café’s Mahlkönig EK43 grinds espresso at about 0–2 on its dial, and two grinders of the same model can differ by a few settings. Dial in by time and taste, then write your own number down.
Pour water into a bucket of pebbles and one of sand: it rushes through the pebbles and seeps through the sand. Too coarse: a fast, sour, thin shot. Too fine: a slow, bitter, dry one, or no flow at all.
On most grinders one click changes the time by 3–8 s (in this studio’s model about 2–4 s per setting). Near the target move one setting, at most two, between shots. Far away (10 s off), take a big jump and split the difference if you overshoot.
A grinder keeps old grounds in its burrs and chute, from a gram to 20 g. Grind a few grams (or a full dose) into the knock box after you turn the dial, or the next shot is part old grind and lies to you.
Finer settings push less coffee out per second: a timed grinder that gave 18.5 g can give 15.5 g after a big move finer. The Smart Grinder Pro doses by time (its GRIND AMOUNT dial moves it in 0.2 s steps), so set the time, then check the dose on the scale.
The same setting runs faster as a bag ages (2–4 settings finer by week 4–5), slower in humid weather, faster in dry heat, differently on a cold grinder. Pull a test shot at the start of every shift and when you open a new bag.
Espresso grounds feel like fine table salt and stick together in little clumps when you pinch them. Gritty like sand: too coarse for espresso.
If even the finest settings run fast (light roasts can), the Smart Grinder Pro’s upper burr, under the hopper, moves one number finer and shifts the whole scale. Use a normal single-wall basket with it, not a pressurized one.
Some grinders have play in the adjustment. Come to your setting from the same direction every time (say, always from coarser), and keep the grinder at its working temperature.
New burrs need “seasoning” (a few kilos of coffee ground fine) before they settle; old, dull burrs make more dust and uneven grounds: sudden flat, harsh shots that no setting fixes. In a busy café, every 4–10 months.
In about 25 seconds, 36 g of water pushes through 18 g of coffee pressed into a cake. It soaks down from the top, dissolves what it can, and carries it out of the bottom. Different flavours come out at different speeds, and that is what you balance.
Catch one shot in five small cups and taste them one by one: the first is thick and intensely sour-salty, the middle ones sweet, the last thin, watery and bitter. A good espresso is a blend of all of them; the ratio decides how much of the end you keep. From the stage’s model of the house blend at setting 14.
Before you taste, the shot has told you most of what you need: when the first drops came, how the stream flowed, when it turned pale, how the crema looks and what the puck looks like after.
Time is the guide; taste is the judge. Learn to tell sour from bitter, then change one thing at a time and taste again. Click a box: what happened, and what would you change?
Sour makes you pucker like lemon, on the sides of the tongue: under-extracted. Bitter is felt at the back, like dark chocolate or a hoppy beer, often dry and drying: over-extracted. Both at once, with a muddy finish: channeling.
Keep it fixed while you dial in. Later, small tweaks fine-tune: +1 g gives more sweetness and body but sharper acidity; −1 g a cleaner, fruitier acidity but a thinner body. Some baristas move in 0.1–0.5 g steps.
Once the time is right, +2–5 g out brings more sweetness and aroma (too much: dry); −2–5 g out keeps more body and fruit. Sour in time: grind finer or pull a little longer. Bitter in time: coarser or a little shorter.
Hotter water extracts more. Light roasts like 93–97 °C, medium 92–94 °C, dark 88–90 °C. Change it by 1–2 °C at a time, not 0.5: you won’t taste half a degree.
Change the grind and the dose together and you never know which one did it. Lock the dose, find the time with the grind, then fine-tune the taste with the yield.
Stir, sip at 60–70 °C, and again at about 50 °C: harshness hides in a hot shot. While dialling in it is fine to spit; you will pull several shots.
The same model as the stage. Pick the coffee and set the grinder, dose, yield, water temperature, preinfusion, puck prep and bean age; see the time, the curve and what it would taste like. Then pull it on the stage.
Each one is a shot of the dialled-in house blend with a single thing wrong. Watch it on the stage, then press “Show the right way”.
Starting points from the sources, not rules: the roaster’s recipe on the bag is the best start of all. Darker coffee extracts easily: cooler, shorter, coarser. Lighter coffee is dense and stubborn: hotter, longer, often finer.
Light roasts have the narrowest window: one setting on the grinder changes them most. Medium to medium-dark is the easiest to dial in and the best in milk. If a light coffee stays sour whatever you do, it may simply suit filter better.
Coffee oil sticks to the shower screen, the gasket, the basket and the spouts, and turns rancid within hours: shots taste harsh, bitter and dirty even when the recipe is perfect. Cleaning is part of every recipe.
Knock the puck out straight away (left in, it keeps leaking oil under the basket), wipe and dry the basket, flush the group for 2–3 s before locking in. A wet or dirty basket gives the water an easy path.
Every 30 minutes, wipe out the portafilter and spouts. Every 40–60 minutes in a busy café, backflush with water: a blind basket in the portafilter, run the pump a few seconds, stop, repeat.
Backflush with espresso-machine detergent, then with clean water. Soak the portafilters and baskets in hot detergent water for about 15 minutes, not overnight: it marks the metal and ruins the handles. Purge and wipe the steam wand.
Take the shower screen off and clean it under running water; check the group gasket. The busiest cafés do it every 45 minutes.
Silicone gaskets outlast rubber ones; a hard, cracked gasket lets water run round the portafilter into the cup. Replace shower screens and baskets every 4–6 months in a café: the holes wear and the shots get dirtier.
Vacuum the chute and burrs every day and take the burrs out for a deep clean once a week. Old oil and fines go rancid and fall into the next dose.
Filtered water at the right hardness protects the boiler from scale and makes a sweeter cup. Never let the tank run dry: air in the pump can damage it. Descale home machines as the maker says.
Most machines run at about 9 bar (home machines 6–9, café machines up to 12). You don’t change it day to day: if the gauge or the temperature wanders, clean first, then call a technician.
The freshest coffee is not the best espresso. Roasting leaves the beans full of CO₂; for the first days the gas fights the water and the shots jump around. After the rest the gas is gone, and slowly the aromas go with it.
Not the best-before date. Rest espresso beans about a week after roasting; light specialty roasts often taste steadier after 2–4 weeks. Use them within 4–6 weeks of roasting.
As the gas goes, the same setting runs faster: expect to go a setting finer every week or two, 2–4 settings by week 5.
A sealed bag with a valve, cool and dark. Not the fridge (moisture and smells). Pour into the hopper only what you will use soon, and close the hopper lid.
Usually a little darker or developed for longer, so it gives up its solubles easily under pressure. You can brew it any way, and you can make espresso with a filter roast: it just needs a hotter, longer, finer shot.
Better gear makes it easier to do the work: steadier temperature, even water over the puck, more uniform grounds. But in a blind test from the sources, a professional barista on a $400 home machine beat a beginner on a $30,000 café machine. Skill comes first.
One small boiler for brewing and steam: switch between temperatures, wait in between. Cheap and simple; slow for milk drinks.
A steam boiler with a pipe of fresh brew water running through it: brew and steam at once. Flush before a shot to settle an overheated group.
A brew boiler and a steam boiler, each with its own thermostat (PID): steady temperature you can set to the degree. Café machines often have one brew boiler per group.
Water heated on the way through: ready in seconds, small and cheap; less steady, and some can’t brew and steam at the same time.
Vibration pumps (home) or rotary pumps (cafés) with a valve that limits the pressure to about 9 bar. Many machines can preinfuse: a few seconds at low pressure before the full push.
Pressurized baskets (a single small hole) fake the pressure for pre-ground coffee; with a good grinder, use a normal basket. Precision baskets (VST, IMS) have even holes. A bottomless portafilter shows you every flaw in the puck.
Burr grinders only (blades chop unevenly). Flat or conical burrs both work; stepped dials click (the Smart Grinder Pro has 60 steps), stepless ones turn freely. Single-dose grinders keep little behind; hopper grinders need purging. Weigh every dose either way.
A 0.1 g scale with a timer, a WDT tool (fine needles), a level tamper that fits the basket, a dosing funnel, a knock box, a blind basket for backflushing.