Feedback from our tester:
First impressions are that it feels weird to tamp with. It doesn’t give a lot of feedback pressure until you’re really leaning on it, I suspect this is due to the gel having some give in it. I did my best to recalibrate my tamping stop to the output of force in my arm rather than the feeling of the coffee pushing back.
I’ll be honest and say I haven’t tried it in place of normal puck prep, their pictures seem to suggest you can tamp with an unlevel (yet somehow evenly distributed) bed of coffee and it makes it ok because it doesn’t unevenly compress the bed. I find that notion to be fanciful at best, but I haven’t tested it.
In place of a normal 58.0mm tamper it is equal at best. The aluminium ring usually caused a different ring around the edge, and the 58.0mm size left something to be desired. At worst it allowed me to tamp in a slightly unlevel manner and that made the gel move more to a level position but the aluminium ring did not, so there’s a step around most of the circumference. Whether that was better than an unlevel tamp from a 58.0mm solid tamper I can’t say. All I know the shots where the bed didn’t look flat after tamping tasted like the extraction was less even, this was matched by the appearance of uneven flow when using a naked portafilter, so I quickly switched to spouted with the double basket.
Discussing this tamper with others online, I learned that perhaps it was actually designed for traditional single baskets, which have very sloped sides and are difficult to tamp well with a normal tamper unless you dose so high that the bed is level at the top. With the idroprep perhaps you could dose a bit lower so that only the gel portion of the tamper interacted with the coffee, and the aluminium ring stayed out of it. This proved to be finicky to achieve as the gel only sticks out 1mm past the aluminium ring.
After all that I still felt like the shape of the basket was causing uneven (yet consistent) flow through the puck. Not harsh like channeling or a really wonky tamp, but tasted off in a way I couldn’t get rid of. Who knows if I could dial it on better if I concentrated on only using this basket for a month, but right now I’d rather have tasty coffee!
