How we rate accessories

Whether a tamper tamps level or a filter filters cannot be read off a listing, so it is left unscored rather than guessed at.

What we can actually read: Deliberately unscored.

Not scored. No specification answers this, so it is left without a number.

This category holds two different kinds of object and one spec sheet does not fit both. A durable is judged on material, warranty and whether parts can be replaced. A consumable is judged on what you get and whether it composts. Asking a sachet of descaler about its warranty produced a paper filter scoring 4.1 and coming last in a category it is probably the most-bought item in.

What we can actually read: Split by item class, so each half is measured against its own peers.

Scored directly from published figures.

3 of the 5 rules below are struck through in this category, because too few makers publish the input. The 2 that remain score this criterion out of 10 between them: a struck rule leaves the sum entirely rather than counting as a zero. That result is then worth 22 of the category's 100 points.

• Material3 of 10

  Not asked of a product whose item class is consumable.

  stainless steel, titanium

  3 pts

  glass, silicone, wood, ceramic

  2.2 pts

  plastic

  1.1 pts

• Warrantynot scored here

  Fewer than one maker in four publishes this here, so its 2 points leave the sum rather than being guessed at.

  Not asked of a product whose item class is consumable.

  none

  0 pts

  up to 1 yr

  0.8 pts

  over 1 yr, up to 2 yr

  1.5 pts

  over 2 yr

  2 pts

• Replacement parts soldnot scored here

  Fewer than one maker in four publishes this here, so its 1.5 points leave the sum rather than being guessed at.

  Not asked of a product whose item class is consumable.

  present

  1.5 pts

• Compostable or biodegradable2.5 of 10

  Not asked of a product whose item class is durable.

  present

  2.5 pts

• Manufacture location publishednot scored here

  Fewer than one maker in four publishes this here, so its 1 points leave the sum rather than being guessed at.

  published at all

  1 pt

10 of 10

Mostly whether it needs other equipment to be any use at all. A knock box works alone; a puck screen needs a machine, a portafilter and a basket.

What we can actually read: Dishwasher safety, dependency on other kit, weight and pack count are published.

Scored from figures that predict it, because the thing itself is not published.

1 of the 4 rules below are struck through in this category, because too few makers publish the input. The 3 that remain score this criterion out of 10 between them: a struck rule leaves the sum entirely rather than counting as a zero. That result is then worth 18 of the category's 100 points.

• Dishwasher safe4 of 10

  Not asked of a product whose item class is consumable.

  present

  4 pts

• Works on its own2.5 of 10

  Also read under Compatibility, which asks a different question of the same fact.

  Not asked of a product whose item class is consumable.

  absent

  2.5 pts

• Weightnot scored here

  Fewer than one maker in four publishes this here, so its 1 points leave the sum rather than being guessed at.

  Not asked of a product whose item class is consumable.

  200 g or less

  1 pt

  over 200 g, up to 600 g

  0.7 pts

  over 600 g

  0.5 pts

• Pack size2.5 of 10

  Not asked of a product whose item class is durable.

  6 or less

  1 pt

  over 6, up to 24

  1.5 pts

  over 24, up to 100

  2 pts

  over 100

  2.5 pts

10 of 10

The criterion that decides whether it fits your machine, which for a 58mm part on a 54mm machine is the only question that matters.

What we can actually read: Brands and models are published, and unusually precisely, because a wrong-fit return costs the seller money.

Scored directly from published figures.

The 3 rules below score this criterion out of 10, and they add up to 10 exactly. That result is then worth 16 of the category's 100 points.

• Brands it fits4 of 10

  3 or more

  4 pts

• Models it fits4 of 10

  5 or more

  4 pts

• No extra kit needed2 of 10

  Also read under Ease of Use & Cleaning, which asks a different question of the same fact.

  Not asked of a product whose item class is consumable.

  absent

  2 pts

10 of 10

Points per pound against the category median, across a category that runs from a $13 packet of tablets to an $80 canister.

What we can actually read: Needs a published price here and on at least three rivals.

Computed from price, not from a rule list

Value is the only criterion here with no thresholds of its own, because it cannot be read off one product. It asks what else the same money buys in this category, so it needs the category. That result is then worth 16 of the category's 100 points.

Points already earned on everything else

out of 10

Multiplied by the category median over this price

median ÷ price

Capped at

10

No price published, or fewer than 3 priced rivals

5 of 10

Half marks is not a verdict, it is a refusal to guess: with nothing to compare against, a product is neither good value nor bad, and scoring it either way would invent a finding. It corrects itself as the category fills.