whats the current trend on tamping pressure? How hard are you guys tamping?

Not very hard. I try to get the coffee settled well by whacking the portafilter on the tamping mat after I dose. Then just a light tamp and polish. I've found that the tamp pressure doesn't make much difference.

Clint Orchuk wrote:Not very hard. I try to get the coffee settled well by whacking the portafilter on the tamping mat after I dose.

I've stoped the practice of hitting the PF on the mat to settle the grounds because if I hit the mat off level, the grounds would suffer. Now I simply dose, re-distribute and tamp. I still use about 30 lbs pressure because that's what I trained myself to use and it works for me.

Why do I tamp the coffee in the filter basket? I believe that the reasons to do so are:
1- Level the coffee puck.
2- Eliminate the gaps and voids in the ground coffee.
Both of these are done to homogenize the coffee density and dimensions. This will in turn create equal resistance to the water flow and produce even extraction.
3- Break the coffee clumps. This is debatable but I believe that a good amount of pressure will effectively separate the coffee clumps or rather will create a big uniform clump (the puck).
4- Create a gap between the group head distribution "screen" and the top of the coffee puck. This is, in my view, necessary condition to allow proper pre-infusion. This, of course is directly related to my machine and my method. I assume that other people reporting different opinions on this are using different machines and/or methods.

If I think of reason 1, the lighter the tamp the easier it is to achieve the level. But, with a little care, I can achieve a level puck with a strong tamp as well.

If I think of reasons 2 and 3, it would make sense that tamping as hard as comfortably possible would help achieve homogenous density of the puck. Although the harder the tamp the denser the puck.

Reason 4, is somewhat unrelated to the tamp pressure as long as the basket is sized in accordance to the dose or vice versa. For people overdosing a basket, a hard tamp would be a good thing.

Based on the above, I concluded that a strong tamp would be preferable.

I have seen a difference in the extraction based on large tamp pressure difference given all other parameters being equal. But this difference is very subtle and difficult to perceive for my limited tasting capabilities. This observation is not based on formal blind testing and in all honesty could be dismissed. Again, this result is based on my machine and methods. I believe my usage of fairly long pre-infusion may be a factor in removing the effect of tamp pressure by allowing gentle swelling of the coffee puck. I also believe that the other parameters can be adjusted to achieve proper extraction with any tamp pressure.

In the end, every so often, I use an Espro tamper to check what a 30 lbs tamps feels like but I almost always tamp with a higher force than that.

The exact method I use is: Groom with WDT, drop in the tamper (Reg Barber, stainless with aluminium handle) to level using only tamper weight, lift tamper to gently suck the ground from the side of the basket, re-insert the tamper and nutate with only finger pressure on top of the tamper. Tamp hard and level, gently lift the tamper off.

I see very little, if any, difference in extraction based on tamping pressure. I give a light tamp with the emphasis on the puck being level, not compressed into a synthetic diamond.

At 9bar brew pressure and a 58mm puck (e-61), the puck is subjected to 464lbs of pressure from the brewing pressure. That's more than I can get into the tamper if I step on the damned thing.

Agree with Greg 100%. I've even fooled around with no tamp and when the pour is finished and I check the portafilter, in appearance there is no difference between a tamped and non tamped puck. I think good distribution is more important, and that's what a thwack on the counter accomplishes for me.