If your basket says 18g, begin with the maker's dose guidance rather than assuming that every coffee must fit identically at exactly 18.0g. Roast, grind and basket geometry affect how much space a weighed dose occupies. The aim is a repeatable recipe that fits your equipment and tastes good.
A dose rating is a reference
The same mass of two coffees can produce different bed heights after tamping. Changing grind can also change how the grounds pack. That is why you should weigh the dose and check its fit again when changing coffee or baskets.
Breville's Bambino Plus manual gives 16–19g for its supplied two-cup baskets. That range applies to those baskets; it is not a specification for every aftermarket 54mm basket.
Do not mix up two product descriptions
The Creamore 54mm detachable-spout portafilter set lists an included 18g Arcflow basket. The separately sold Arcflow 54mm basket variant lists an 18–22g dose range and a 53.3mm tamper recommendation. Use the guidance for the actual item in your hand. Do not assume the upper end of a separate product's range applies to the bundled basket.
Check headspace without chasing a universal gap
Headspace is the clearance between the tamped grounds and the shower screen. Follow your machine and basket instructions for dose height. Where the machine supplies a dose trimming tool, use it as directed with the intended basket.
With the pump off, lock in the prepared portafilter and remove it to check for obvious dry contact or disturbance from the shower screen. If it is difficult to lock or the dry puck is being compressed, check for overfilling and fit problems. Do not force it. A mark on a wet puck after brewing is less conclusive because the puck changes during extraction.
There is no single coin-test result or millimeter gap that proves the best dose for every machine. Adding a puck screen also uses space, so reassess the dose when you add one.
Adjust in small, measured steps
- Start within the basket maker's stated range and weigh the grounds.
- Distribute evenly, tamp level and check that the assembly seats normally.
- If the dose is too high, reduce it slightly, for example by 0.5g, and check again.
- Once the dose fits, keep it constant while dialing the grind and beverage yield.
- Record the coffee, dose, yield, time and taste so the next comparison is useful.
A wet puck is not a taste test
Standing water or a soft puck can reflect the dose, basket geometry and the machine's pressure-release behavior. It does not establish under-extraction on its own. Likewise, a dry puck does not prove that a shot tastes balanced.
Taste the espresso and compare repeated shots. If you consistently want a dose outside a basket's intended range, choose a suitable capacity after confirming fit. Increasing the dose simply to produce a tidier puck can make your recipe harder to repeat without improving the cup.