Accessories
Knock Boxes and Puck Disposal Explained
A knock box is a small accessory that solves a genuinely annoying problem: what to do with a used, compacted puck, several times a day, without making a mess.
What a knock box does
A knock box gives you a padded surface to knock the spent puck out of the portafilter, containing the mess and protecting the portafilter's edge from repeated impacts on a hard countertop, which over time can actually damage the portafilter rim.
Types
Open-top knock boxes are simple bins; drawer-style knock boxes/bins hide the mess and are common in cafés and larger kitchens, usually holding more pucks before needing to be emptied.
Do you actually need one?
It is not strictly required — some people knock pucks directly into a compost bin or trash — but a dedicated knock box reduces mess and protects your portafilter from wear over time, which is a real if slow-developing cost of repeatedly knocking against an unpadded edge.
What to look for if you buy one
A knock bar (the raised bar you knock the portafilter against) that is genuinely padded rather than just a rubber-coated metal edge, and a container large enough that you are not emptying it after every single shot, are the two practical differences between a good knock box and a frustrating one.
Composting used pucks
Spent espresso grounds are commonly composted, and many knock boxes are designed to have their bin removed and emptied directly into a compost container — worth checking before buying if this matters to you, since some designs make this easier than others.
Placement matters as much as the box itself
A knock box positioned within an arm's reach of the group head, rather than across the counter, is the difference between a habit that sticks and one that gets skipped in favor of just rinsing the portafilter under the tap. Factor this into your kitchen layout (see our machine-placement guide) rather than treating it as an afterthought.