Before I get flamed, I realize that distribution is the key here but just for discussion, I've been thinking about which would be more important, a flat tamp or a tamp that applies equal pressure to the puck?

IOW, if the distribution is off and you're too lazy to fix it, is it better to tamp flat knowing one side of the puck has a higher tamp pressure than the other side or would it be better to apply the same tamp pressure to the puck knowing one side will be thinner than the other side?

A tricky question but I was reading the Pullman website where they state:

TrueTamp rings for a consistent and level tamp

I began to wonder which would be better? For me, if I notice my bed of grounds is off level when I tamp, I just get my needle out and WDT the bed back to flat.

If your distribution is off, your tamp will be uneven, or if you just favor one side of the tamper more than the other. The end result is part of the puck will be denser than the other. Water will take the path of least resistance which means the less dense portion of the puck is what will get extracted while the denser side will be blank. In the grand scheme, having the tamp level is more important than the tamp pressure provided you are reasonably consistent with the pressure. A 2 pound tamp followed by a 100 pound tamp may be an issue but a handful of pounds either way is not detrimental. Now days I tamp lightly only using two fingers. I just want to settle the grinds in the basket to an even level/density.

I would say with one, you have the other.

Level distribution -> Level tamp. If you have a level tamp, it implies pressure is even.

So why doesn't a convex tamper lead to doughnut extractions?

A concave tamper would lead to doughnut extractions since the center of the puck would be deeper than the outer portions. Convex would help lessen the chance of doughnut extractions since it'd create a tamped puck that is thinner in the center.

SO.. a concave tamper makes doughnut HOLE extractions?

If i have a lazy barista, i would look for an other one!
...if you are that barista, I would change my espresso machine, for a coffee machine!

if none of those are an option, then... i think distribution is more important than tamping pressure.
If its equally distributed, even if the coffee doesnt apply resistance to the water, it will be the same thru all the filter. so you shouldnt have channeling


(Sorry for my english)

Randy G. wrote:A concave tamper would lead to doughnut extractions since the center of the puck would be deeper than the outer portions. Convex would help lessen the chance of doughnut extractions since it'd create a tamped puck that is thinner in the center.

SO.. a concave tamper makes doughnut HOLE extractions?

Start with a level untamped basket. Tamp straight down with a convex tamper. The center gets tamped more than the edges.

HB wrote:If you're too lazy to start over, it doesn't matter since it will channel either way. But as an espresso imponderable, a canted tamp will result in channeling even if the distribution is perfect. So if you find yourself in the dilemma of this lazy barista, I recommend keeping the tamp level and not trying to "correct" the distribution gaffe with another gaffe. Or, better yet, try nutation with the hope that it improves the distribution...

+1 on all this. That's how nutation works: not to tamp the puck, but to improve the distribution before the actual tamp. The distribution tool happens to be the tamper, rather than your finger or a dissecting needle.

allon wrote:Start with a level untamped basket. Tamp straight down with a convex tamper. The center gets tamped more than the edges.

This would be true, except that grinds in the untamped puck are still free to redistribute. It's likely that a convex tamper pushes grinds away from the center as you begin to apply pressure, which tends to alleviate donut extractions.

RapidCoffee wrote:+1 on all this. That's how nutation works: not to tamp the puck, but to improve the distribution before the actual tamp. The distribution tool happens to be the tamper, rather than your finger or a dissecting needle.

+1