# Tamper "snugness" - 58mm vs 58.5mm



## BucketMan (Dec 23, 2020)

So I got an IMS 58mm basket, I only had a 58.5mm tamper, so I got a 58mm tamper in the same order. When trying out the 58mm with the new basket I noticed a lot of space around the edge and the 58.5mm fits a bit more snuggly in it.

I've noticed that coffee can clump on the side of the 58.5mm tamper which I have to wipe off, is this an indication of an incorrectly sized tamper or my poor tamping/distribution skills?

I feel like I'm going mad! Today I got a Motta levelling tool, 58mm, loads of wiggle room in the 58mm basket 🙃

My question is, how snug do you want it to be? Should there be a bit of wiggle or not?


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## hotmetal (Oct 31, 2013)

In my experience it's no biggie either way, but it is better to have it fit snugly so the tamper doesn't need a second go. When I started out I had a "58mm" tamper that was actually closer to 57.5. In my VST basket I always felt like I had to move it around to seal all the edges. Buying a Torr precision tamper that fits the basket properly is a lot more confidence inspiring and gives a good seal all round. Yes, sometimes there's a little bit of coffee on the edges of the tamper but I subplot simply brush it off. I don't think it makes any difference, as it's likely less than 0.1g, so isn't going to make any difference to your ratio. Tamping is about sealing the edges and evening out the density so all air pockets are removed and the water travels evenly through the puck, which should be flat/level. A good fitting tamper makes this easier.


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## rogher (Nov 22, 2020)

An interesting question.

You don't want an 'interference' (perfect) fit or your tamper may jam but the cleaner the puck the better, I think. If any excess rides up it may get between the portafilter and brew head seal - but you'd clean that off anyway(?). I don't think the lack of pressure being applied right up to the sides would make much difference. If coffee grounds behave like soil, the pressure will spread outwards at about 45° so it's not as if you'd be leaving a cylinder of weakly pressed grounds around the outside. The filter basket holes do not spread to that diameter, either, so I assume that most of the water passes through the centre if the puck is evenly compressed.


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## ajohn (Sep 23, 2017)

It's clumping on the tamper because it's pressing grinds harder up against the edge of the basket than the smaller one. I get the same thing with a 58.4mm levelling tool. What I should do is find my 58mm one and offset it to the side of the basket and rotate it while keeping it in contact as nothing clumped used like that.

A 58mm tamper can be used like that as well by polishing with it offset. Flattens right to the edge. I now use a 58.4mm and that leaves ug of loose grinds that I just blow off. No different to using the 58 offset really.


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## 27852 (Nov 8, 2020)

If you go too snug you can undo your good work by a vacuum pulling up the puck. In the grand scheme of things it's not too big a deal, there are probably other things you could do to "improve" the shot (or not, if it's tasty coffee rock out).


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## BucketMan (Dec 23, 2020)

Thank you for the thoughts everyone! I levelled up several times in one go, a gaggia classic to a profitec 600 so I could be being a little too precious about everything but consistency is key here!


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