The only tamper I've known is a Reg Barber flat. I like have always liked it and never felt a pull to change.

An interesting discussion of tamper shape. Seattle Barista Academy recommends that a flat bottom on the tamper. The rational is that a flat pack will more likely lead to an even extraction. It is thought, and some of their 'experiments' seem to support this idea, that the rounded pack can lead to overextraction because of pooling and underextraction at the sides of the pack. Hope this helps the discussion. Regards. Jeff Burgess, Director of the Seattle Barista Academy.

It doesn't matter, at least for me. But maybe the outcome would be different depending on the machine, grinder, and beans?

Interestingly enough about 2 months ago I walked into this restaurant supply store in Perth where they have a self-serve 2 group machine by the door free to use for customers. The person who brought me there said they use it all the time, but of course I had my doubts about the quality, I gave it a go anyways. There was no tamper here, just the one attached to the grinder. So I dosed some grounds and tamped lightly, and pulled a pretty good shot! It wasn't fantastic but shockingly good. Perhaps it has something to do with a coffee roastery on site. Just to prove it wasn't a fluke I did it again on my way out

Moral of the story? Perhaps tamping is overrated, maybe I'll attach the tamper to my mazzer and start using that

bobroseman wrote: >Total engineering geek-out snipped< ; >
What is clear is that the edge will be 1.6 mm thicker and very slightly less compacted.

'Kay Bob, what if the bottom of the basket emulated the gentle curve of the tamp? Wouldn't those two surfaces, being parallel, pretty much even out the force all across the surface and compact the puck evenly? Would that make the curved tamp appropriate for curved basket-bottoms?
It's the 'LM-styled' 14G baskets tha tI got from 1st Line a few years ago. Came with a gentle curve, reminiscent of the 'American Curve', and seems to perform a tiny bit better with the curved tamps.
Just a hunch, mind you...

shadowfax wrote: [snipped]

Or you just won't improve because you're lazy, and complain about how you wish you had a different type of tamper, because of course, if your espresso sucks, it's your equipment, not your technique, right?

Interesting you say that. I somewhat equate folks having 4 or 5 tampers for the SAME machine as to golfers who constantly "upgrade" their putter,(or ALL their clubs) as that is easier than practicing, or maybe improving technique with lessons. Having said that, I do think it's fun having both a flat and convex as I do for my Cremina.
What I've found is for my smaller cremina basket, the thinner piston of my Richard Penney tamper helps me level a bit better, while my 58mm Reg's thicker piston did the trick for that basket size. Might be just me.

lol. Put down the tampers and go outside people!

We did.....last summer!