Three things shape an espresso before water touches it: the grind size, the dose of coffee in the basket and the tamp that presses it into an even bed. Consistency here is the foundation of good coffee.
Why it matters
Small changes here make big changes in the cup. Consistent technique means every guest gets the same drink, whoever is on the machine.
Key ideas
Grind size
Finer coffee slows the water; coarser coffee speeds it up. Adjust in small steps and test after each change.
Weighing the dose
Weigh the coffee on scales, for example 18 g for a double, as your recipe says. Guessing by eye is rarely accurate.
Even distribution
Spread the coffee evenly before tamping. Gaps or clumps let water rush through weak spots, called channelling.
Step by step
- 1
Wipe the basket clean and dry.
- 2
Grind fresh coffee into the portafilter.
- 3
Weigh the dose and adjust it to the recipe.
- 4
Level the grounds, then tamp straight down firmly.
- 5
Wipe the rim clean, lock in and brew.
Do
- Keep your wrist straight and elbow above the tamper.
- Check the tamp is level by looking from the side.
- Grind just before brewing, as ground coffee goes stale quickly.
Common mistakes
- Don't knock the portafilter after tamping; it cracks the bed.
- Don't tamp at an angle; a sloped bed brews unevenly.
- Don't leave ground coffee sitting between orders.
The situation
Your shots suddenly run much faster, though nobody has changed the grind.
What a professional does
You weigh the next dose and find it two grams light because the hopper is nearly empty. You refill it, re-weigh and pull a test shot.
Useful phrases
“Can you refill the hopper? My doses are coming out light.”
“One minute, I'm just dialling in.”
Pro tip
Tamp the same way every time; consistency matters more than force.
Quick check
What is channelling and how do you prevent it?
Think about it, then show the answer
It is water rushing through weak spots in the coffee. Spread the grounds evenly and tamp level to prevent it.