Hello,
I have a Bezzera BZ10, with the original 14g basket and I buy the original tamper, made by Bezzera (link). But I noticed immediately that the tamper don't fit the basket! Look here:



If I press in the middle, 1-2mm of grind around the tamper, remains incomplete pressed, and the coffee stick to the edges of the tamper. Must to knock, and press for another two times to cover all the surface of the puck.

The vendor say that "this tolerance between tamper and filter is absolutely wanted, it does not matter if there is 1mm space at the side."

What do you think? Is a matter of technique or is better to sell this tamper and buy a Reg Barber (for example) with the exact fit diameter?

It's a matter of preference, but I agree with the vendor. Some baristas like a piston that fits tightly to push every grain of coffee down, others want a bit of slack so they can experiment with nutation. I go with the looser fit and do a NSEW "Staub" tamp if I'm feeling that OCD thing.

I have a LM single basket and I tamp with the small end of a plastic Faema tamper. There's always coffee on the edge of the basket that refuses to be tamped, and it doesn't make any difference.

Tamping is overrated in my opinion.

it's easy to get the idea that one must be completely fastidious when preparing the basket for espresso. I, too, worried about this so I bought a tamper that fit perfectly. I do not like it. I get more channeling with it and it's hard to use - you have to position it just so to get it to fit - so I went back to a tamper that fits about like yours - but I do not tap the side - I broke myself of that, even though it feels good. I just tamp, brush the excess off the top of the portafilter, loosely polish and go. Sometimes it's perfect, sometimes it's not, but it's always better than I can get in a local coffee shop.

I agree with the above posters. I have a Reg Barber that i ordered purposefully loose for my setup.

It also gives you some latitude if you ever change baskets and find one that is not exactly the same diameter. Buy a fitted tamper and it may not work in your next basket.