A thin tempered glass mirror that sits on your cup's rim, so you can watch a bottomless portafilter shot without crouching down.
A bottomless portafilter (one with no spouts, so you see the coffee leave the basket) tells you a lot about a shot, but only if you can see underneath. This mirror rests on the edge of your cup, close to the basket, and a stiff wire on the back lets you bend it to the angle you need. The glass is ultra-thin, edgeless and tempered, and the whole thing weighs 38g.
It suits anyone dialling in espresso who wants to spot channelling: water finding a weak path through the coffee, which shows up as spurts or pale streaks. An adhesive magnetic dot sticks to your machine or wall, so it’s always within reach. It fits most cups, though very narrow-based cups can tip.
Tip: if one side of the basket goes pale early, look at your distribution before you change the grind. Stirring the grounds evenly often sorts it.
