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Learn home espresso
The whole beginner curriculum: your first shot, dialing in, the drinks, the vocabulary and the technique.
The espresso glossary
Every term on this site, defined in one line. No circular definitions, no assumed knowledge.
By Scooter M. · Published
Espresso has an unusual amount of jargon for something you do with two ingredients. Here is all of it, in one line each, in the words you would use to explain it to someone standing in your kitchen.
The equipment
| Term | What it means |
|---|---|
| Portafilter | The handled holder you lock into the machine. It holds the basket |
| Basket | The metal cup inside the portafilter that the coffee goes in |
| Single-wall basket | A basket with many small holes. Honest about your grind |
| Dual-wall / pressurized basket | A basket with one small hole that forces crema regardless of grind. Forgiving |
| Bottomless / naked portafilter | A portafilter with no spout, so you can watch the puck pour. More |
| Group head | The part of the machine the portafilter locks into |
| Shower screen | The perforated disc in the group head that spreads water over the coffee |
| Group gasket | The rubber seal the portafilter presses against. A wear part |
| Tamper | The flat tool that compresses the coffee. More |
| WDT tool | Fine needles for stirring dry grounds to break up clumps. More |
| Distributor / leveler | A tool that flattens the surface of the coffee bed |
| Knock box | A padded bin for spent coffee pucks |
| Steam wand | The metal tube that produces steam for texturing milk |
| Panarello | A plastic sleeve on a steam wand that adds air automatically. Makes stiff foam, not microfoam |
| Blind basket | A basket with no holes, used for backflushing |
The process
| Term | What it means |
|---|---|
| Dose | The weight of dry coffee going into the basket. Usually about 18 g |
| Yield | The weight of liquid espresso coming out. Usually about twice the dose |
| Ratio | Dose to yield, by weight. 1:2 is the reference. More |
| Extraction | How much of the coffee's soluble material the water dissolved |
| Under-extracted | Not enough dissolved. Tastes sour and thin. Grind finer |
| Over-extracted | Too much dissolved. Tastes bitter and drying. Grind coarser |
| Dialing in | Adjusting until the shot is repeatable and good. More |
| Channeling | Water finding an easy path through the puck. More |
| Puck | The compressed disc of coffee, before and after the shot |
| Puck prep | Everything between grinding and locking in: declumping, leveling, tamping |
| Pre-infusion | A few seconds of low pressure before the shot. More |
| Backflush | Pushing water backward through the group to clear oils. More |
| Crema | The foam on an espresso: carbon dioxide emulsified with coffee oils |
| Blonding | The point in a shot where the stream turns pale — extraction is finishing |
Grinding
| Term | What it means |
|---|---|
| Burr | Two surfaces set a fixed distance apart that crush the beans. More |
| Conical burr | A cone inside a ring. Common at home |
| Flat burr | Two flat rings facing each other |
| Stepped adjustment | Grind settings in defined clicks you can count. More |
| Stepless adjustment | Continuous adjustment with no clicks |
| Retention | Ground coffee left inside the grinder between doses |
| Single dosing | Weighing beans for one shot rather than filling a hopper. More |
| Hopper | The container of beans that sits on top of a grinder |
| Fines | Very small particles produced alongside the target grind size |
Milk and drinks
| Term | What it means |
|---|---|
| Microfoam | Milk with air folded in so finely no bubble is visible. Pours like wet paint |
| Foam | Milk with visible bubbles. Sits on top rather than folding in |
| Stretching | The first phase of steaming, where air is introduced |
| Texturing | The second phase, where the air is folded through the milk |
| Splitting | Milk curdling into acidic coffee. Common with standard plant milks. More |
| Barista edition | Plant milk reformulated with extra fat and stabilizers so it foams and resists splitting |
Machines
| Term | What it means |
|---|---|
| Semi-automatic | You grind, dose and tamp; a pump supplies pressure |
| Super-automatic / bean-to-cup | The machine does everything. No portafilter. More |
| Manual lever | You supply the pressure yourself |
| Thermoblock / thermocoil | A heating element water flows through. Fast to heat, less thermally stable |
| Boiler | A tank of heated water. Slower to heat, more stable |
| PID | A controller that holds temperature at a set point rather than letting it swing |
| Bar | A unit of pressure. Espresso brews at about 9 bar; pumps are rated higher |
| Three-way valve | Releases pressure after a shot. It is what makes backflushing possible |
| Descaling | Removing mineral scale from inside the machine. More |
No products on this page. A glossary is reference content and nothing here recommends a purchase. Attaching product picks to a definitions page would be a tenuous fit, and a bare page is the right call.
Questions people actually ask
What is a portafilter?
The handled holder that locks into the espresso machine. The basket sits inside it and the coffee goes in the basket.
What is the difference between a single-wall and dual-wall basket?
A single-wall basket has many small holes and reflects your grind honestly. A dual-wall or pressurized basket has one small hole that forces crema regardless of grind, which is forgiving while you are learning.
What does dialing in mean?
Adjusting your grind, dose and yield until the shot is both good and repeatable. In practice it usually means adjusting the grind until a fixed dose and yield land in the right time window.
What is microfoam?
Milk with air folded in so finely that no individual bubble is visible. It pours like wet paint and blends into the coffee, as opposed to foam that sits on top.
Sources
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