Hi all, I currently use a motta 58mm tamper with my 18g IMS basket and there is a definite gap between the tamper and the edge of the basket.

What I’m not sure about is what tamper size I actually need: 58.4, 58.5 or even 58.55 (this size might be Lelit specific)? The Bella Barista website says 58.4 fits the IMS basket perfectly but I think plenty of people on here use 58.5mm tampers. Do I need to worry this much about 0.1mm?!

Using a Profitec Pro500 with bottomless portafilter.

Haha I did not even know motta has all those versions of the tamper. You can probably get a calliper to measure the bore of the IMS basket or you may find the specs of the basket on their website. On my VST I measured 58.72 so it would probably fit even the 58.55, but I have 58.5 version and I get a pretty decent fit.

Mark-drinks-coffee Sorry, I need to ask: IIRC? ISTC?!

I’m sure I’ll feel very silly for asking but they are new to me!

Actually, not silly at all. I’ve spent a lot (far too much, probably) of time in forums over the years and tend to drop into lazy habits far too easily. I just kinda presume everybody knows those sorts of acronyms, and not everybody does. Sorry, me = LG (Lazy Git). 😁

FYI– I have just measured a n 18 gram VST=. 58.8 mm.

I would not get too hung up on a precise fit as it can be detrimental. If you are not very careful removing the tamper it is quite easy to lift the puck with the vacuum created by the close fit.

Baristas have been making good coffee without precision tampers for many years.

    Elcarajillo

    Thanks! 👍

    The IMS tech specs says the internal dimension is 59mm so I’ve ordered a 58.5mm tamper. There is a definite ridge of coffee with my current 58mm tamper so hope this new one avoids that.

    You should be fine with that size👍. Before precision tampers, baristas did the N S-E W tamp to compact the stray grounds.