another_jim wrote:Abe Carmeli is visiting, and choked a shot using the same coffee, grinder, grind setting, weight, and machine when it flowed fine for me. I nutated then did a pro forma 2 pound tamp, whereas he nutated then did a heavy 30 pound tamp.

As James and Nicholas observed, nutating tamps can have unpredictable effects. That's why I prefer to call them by their more accurate name, "mutating tamps."

Also, that's why I'm trying to train myself not to use them anymore.

I'm beginning to think there's some sort of alternative LM espresso universe where nothing works quite the same. Nutating tamps have turned my espresso experience boringly predictable.

BTW, I never press down; The mutation may be caused by pressing down while nutating, which would send in the pressure non-vertically.

I have a question somewhat on topic...

For a non-PI machine, such as my bz07 - would a bit firmer tamp/standard 30# be helpful in preserving the coffee bed? Every since I read a post from OE about them dreading "full brew pressure slamming the puck" in reference to pump machines, I can't help but think of it every time I hit the brew button

King Seven wrote: However, I've seen shots slow waaaaay down when nutating quite aggressively in the tamp. Which kind of freaks me out.

If that were happening to me, I'd suspect that I was having issues sealing the puck to the sides, and getting some side channeling all around the edge. But since it's you... yeah it freaks me out a little as well.

I did notice, however, that tamps on the lever *(Gaggia Factory) tend to reflect themselves consistently in the pressure required to mash down the lever handle. If I tamp hard, it takes more weight to get the same flow as if I tamped lightly. Not a bunch, but noticeable.

My espresso started to become more consistent when I switched to a "consistent" lighter tamp with finer grind.

At a common sense point of view its quite clear you can get the results. Its all about how much resistance there is for water travel through a certain path. When I realized this I experimented with a lighter tamp and finer grind a used taste as a measure.

It has also saved my back/body using a finer grind and make me look less restarted when making coffee.
I see a lot of voodoo coffee making techniques by home baristas, when I see how the pros do it, the technique is usually less fussy and more simplistic.