Coffee terms explained

A bean-to-cup machine takes the whole process off your hands: it grinds, tamps, brews and drops the puck into a container you empty now and then. You never touch the coffee.

That is the reason to buy one and equally the reason not to. You have little influence over the result, and what comes out is consistently good rather than occasionally exceptional.

See also: Portafilter machine, Brew group

On a portafilter machine you do every step. You grind, weigh, tamp and lock the portafilter into the group head. The machine only supplies water at pressure and temperature.

The result therefore depends on you. That is a pleasure if you enjoy it, and a daily irritation if at seven in the morning you only want coffee.

See also: Bean-to-cup machine, Portafilter, Tamping

Espresso is not a kind of bean but a method: hot water is forced under pressure through a compressed bed of ground coffee. A double shot is roughly 16 to 20 grams of coffee yielding 40 to 60 millilitres in about 25 to 30 seconds.

Everything on this site is about that method. A machine that does it well handles cappuccino and latte macchiato as a matter of course — that is the same espresso with milk added.

See also: Extraction, Crema, Ristretto and lungo

Too short or too coarse and you pull too little: the coffee tastes sour and thin. Too long or too fine and you pull too much: bitter and drying. Between the two sits a window a few seconds wide.

Nearly every setting on a machine — grind, dose, temperature, pressure — exists so you can hit that window.

See also: Grind size, Channeling, Pre-infusion

Almost every machine here quotes 15 or 19 bar. That is what the pump can deliver at most, not what reaches the coffee. The usual pressure for espresso is about 9 bar, and an over-pressure valve holds it there.

More bar therefore does not mean a better machine. It is a number that looks good on a box.

See also: Over-pressure valve (OPV), Extraction

The valve that separates what the pump can do from what the coffee gets. Without it, 15 bar would break the coffee bed open and the water would run past it rather than through it.

On some machines the valve is adjustable. On most in this range it is not, which for most people is fine.

See also: Pump pressure and bar, Channeling

A few seconds of water at low pressure lets the grounds swell and close up before full pressure arrives. The water then finds it harder to take a shortcut.

The difference shows most with lighter roasts and fine grinds. Machines also call it low pressure pre-infusion.

See also: Channeling, Extraction

Crema forms because carbon dioxide still trapped in the bean is emulsified into the coffee under pressure. Fresh beans give more of it than old ones.

It is an indication, not a seal of quality. A machine with a pressurised basket can whip thick crema out of poor coffee, and excellent light-roast coffee can give very little.

See also: Filter basket, Espresso

On a bean-to-cup machine the brew group is a unit that compresses the coffee, pushes water through it and ejects the puck. On Philips, Siemens and Melitta you can take it out and rinse it; on Jura and De’Longhi it is partly fixed and the machine cleans it itself.

Removable is easier to maintain. It is no guarantee of a longer life, but it does make visible how dirty things get inside.

See also: Bean-to-cup machine, Descaling

The size is quoted in millimetres and decides which baskets and tampers fit. Every Sage machine here uses 54 mm; heavier commercial machines usually use 58 mm.

Heavier and thicker is generally better, because the mass holds temperature during the shot.

See also: Filter basket, Tamping, Portafilter machine

A single wall basket makes the result depend entirely on your grind and dose. A dual wall basket has a small hole that builds artificial back-pressure, so even pre-ground coffee produces crema.

Sage ships both. Start with dual wall if you have no grinder yet, and switch once you grind fresh.

See also: Crema, Grind size

Sage specifies 10 to 15 kilos of pressure in its manuals. More important than the force is that it is level: a sloped bed lets water through faster on one side.

The Barista Express Impress takes this step over with a lever, automating precisely the part where most people make the difference.

See also: Channeling, Portafilter

If the bed is unevenly compressed or cracked, the water takes the path of least resistance. That part of the coffee is over-extracted and the rest under — and you taste both at once.

Sloped tamping, too coarse a grind and an overfull basket are the usual causes. Pre-infusion helps, but will not rescue a badly filled bed.

See also: Tamping, Pre-infusion, Extraction

A ristretto is the same dose with less water: shorter, thicker, sweeter. A lungo runs longer: more volume, and past a point the bitter compounds you would rather leave behind.

On a bean-to-cup machine these are buttons. On a portafilter machine it is simply when you stop.

See also: Espresso, Extraction

Finer means more resistance, so a slower flow and a stronger extraction. Coarser does the opposite. It is the first thing to change when a shot runs too fast or too slow.

Change one thing at a time. Adjust grind and dose together and you will not know afterwards which made the difference.

See also: Grind settings, Extraction, Channeling

More settings means smaller steps between too fast and too slow. The Sage Barista Express has 16, the Impress 25 and the Barista Pro 30; the Philips bean-to-cup machines have 12.

On a bean-to-cup machine the count matters less, because the machine manages dose and flow itself. On a portafilter machine it is exactly where you notice the difference.

See also: Grind size, Burrs

Burrs break the bean between two toothed surfaces, producing a more even grind than a blade grinder, which smashes it. Nearly every machine here uses conical steel burrs.

Ceramic wears more slowly and stays cooler; steel is sharper and grinds faster. The difference in the cup is small next to the difference between fresh and pre-ground.

See also: Grind size, Grind settings

A metal block with a channel through it. Water is heated as it passes, so the machine is ready in tens of seconds rather than minutes.

The trade-off is that little hot water is held in reserve: brewing and steaming back to back means waiting. Nearly every machine under a thousand euros works this way.

See also: ThermoJet, Thermocoil, Boiler and dual boiler

Sage uses this name in its manuals for the Bambino and the Barista Pro. It is a flow-through system like a thermoblock, built to reach temperature in seconds.

We keep the maker’s own word rather than equating it with a thermoblock, because that would be a judgement Sage does not make.

See also: Thermoblock, Thermocoil

A heating element cast into a water-carrying block. Sage calls it this in the manuals for the Barista Express, the Impress and the Touch.

In practice the difference from ThermoJet is mostly heat-up time, not the cup that comes out.

See also: Thermoblock, ThermoJet

A boiler holds water at temperature rather than heating it on the way through. That costs heat-up time and buys stability across longer sessions.

With two boilers a machine can sit at brew temperature and steam temperature at the same time. No machine in this range has that; it starts above it.

See also: Thermoblock, Steam wand

A wand that blows steam into the milk. You decide how much air goes in and when to stop, and that is exactly the difference between microfoam and bath foam.

It takes practice — a week or two — and then gives a result no automatic system in this price range matches.

See also: Microfoam, Automatic milk system

Well-textured milk is glossy and liquid, like wet paint, and pours into the cup rather than sitting on top of it. Coarse bubbles float and collapse within a minute.

Whole milk is the easiest to texture; plant milks need a barista version made for it.

See also: Steam wand

A tube into a milk carton, or a jug you clip on. One button produces a cappuccino without you touching anything.

The part that decides whether you still like the machine in three years is how easily this cleans. Philips’ LatteGo is two parts with no tubes; systems with pipework need a daily rinse cycle.

See also: Steam wand, Brew group

Scale deposits where water is heated and slowly closes the flow down. Every machine here asks for it itself, based on the number of brews and the water hardness you set.

Ignoring it is the most common way to kill a bean-to-cup machine. Set the water hardness straight away — otherwise the machine asks too late.

See also: Water hardness, Water filter

Every machine ships with a test strip. Dip it, read the value, set it in the menu — after that the machine knows how often to ask for descaling.

It takes a minute and it is the most commonly skipped step of setting up.

See also: Descaling, Water filter

Philips calls it AquaClean, Jura uses CLARIS. The cartridge reduces the scale entering the machine, so it needs descaling less often.

They are consumables, and over a few years they add up. Count them in when comparing two machines on price.

See also: Descaling, Water hardness

Makers quote the capacity in servings rather than litres, because that is the number you can act on: it is how many coffees before the machine interrupts you. Philips counts on 12 pucks, Jura on about 16.

A bigger container mostly matters when several people drink from the same machine.

See also: Brew group

When a shop shows “was €699”, that is a claim by the party selling the thing, not by the manufacturer. We record it under the shop’s name and repeat it as something they say.

We keep that claim per day. A discount is more often manufactured by raising the reference than by lowering the price, and only a dated record can show it.

See also: Price verdict

We measure every machine’s price daily and compare today against what we saw before. That produces “lowest ever”, “sharp”, “average” or “dear”.

While there are too few measurements, we say so. We never base the verdict on a shop’s struck-through price — that is exactly how comparison sites end up promoting permanent discounts.

See also: Reference price