wilburpan First, given enough force, any differential in density should go away, given that coffee is not compressible. This is basic physics.

If this were true, tamping flat, without distributing would be as efficient as any other method. I think quite a few people have tested and found that distributing before tamping increases efficiency. I was in conversation with friend who supplied with data (for his machine & grinder) that showed hard tamping definitety lowered extraction…so being flat isn’t all there is to it.

      wilburpan interesting. I’ll have to get my non-levelling tamper out and see what I get from a lopsided distribution

        MWJB If this were true, tamping flat, without distributing would be as efficient as any other method.

        Hm - no. The amount of force/pressure needed to shift the grounds against their mutual friction may be well above the amount of force/pressure that allows maximal (or optimal - not necessarily the same) extraction. It remains a physical fact that, given enough force, the differential in density will go away.

        With all respect (and I mean this), you keep confusing statements that are about the basic physics of things with statements about what is optimal for coffee making. See our prolonged discussion on the weight of burrs.

        MWJB being flat isn’t all there is to it.

        Definitely not, as far as having a good coffee is concerned. However, it seems that having a level puck pre-tamping isn’t all there is to it either. 😁

        • MWJB replied to this.

              CoyoteOldMan With all respect (and I mean this), you keep confusing statements that are about the basic physics of things with statements about what is optimal for coffee making.

              It’s not so much confusing between physics & optimal coffee making, more focusing on the coffee making aspect, because that is the end result we are aiming for.

                  MWJB wilburpan First, given enough force, any differential in density should go away, given that coffee is not compressible. This is basic physics.

                  If this were true, tamping flat, without distributing would be as efficient as any other method. I think quite a few people have tested and found that distributing before tamping increases efficiency. I was in conversation with friend who supplied with data (for his machine & grinder) that showed hard tamping definitety lowered extraction…so being flat isn’t all there is to it.

                  Just to clarify, it did take more time and attention to make the uneven bed flat with just the tamper, so I’m not saying that there’s no benefit for leveling, nor am I saying that it’s just as efficient. Like I said, I’m going to keep leveling and doing WDT.

                    MWJB because that is the end result we are aiming for.

                    In which case - and again, with the greatest of respect - I think you incorrectly attribute to others the same singularity of purpose you have. Plus, some of us - even if we share that purpose - need to reason some things through step-by-step; either because we are less intelligent, or because we have less of an encyclopedic knowledge of coffee making and are thus not able to make the same ‘leaps’ in reasoning that you make.

                    • MWJB replied to this.

                        CoyoteOldMan I doubt that I am any more intelligent that most here, probably less so than plenty of members.

                          Ernie1 Also do different machine types have different ramp-up times? I should know this having owned more than one machine

                          They most definitely do…and this makes a big difference.

                          Contact me

                            So I had a go at back to back even vs uneven puck prep.

                            • Shot 1 (19g in 38g out in 32s - this is a pressure profiled shot)

                              • I gave it a side tap so the grounds were heaped up on one side. I then did a single tap to level the bed and tamped with my self-levelling tamper.
                              • Visually the puck looked fine and level, but the bottomless portafilter told a different story.
                              • The side where it was heaped had very slow flow. The other side was very fast and blondes quite quickly.
                              • Although the overall time wasn’t too bad I think it over extracted one side of the puck and under extracted the other.
                              • Taste-wise it was quite bitter and it ended up going in the sink. I couldn’t get any of the origin flavours.

                            • Shot 2 (19g in 38g out in 35s with the same pressure profile)

                              • This time I did a wdt level, tap to settle the bed and then tamp (same tamper with the same pressure)
                              • the shot ran evenly across the bed as you would expect for a decent shot
                              • taste was delicious. Balanced, sweet and reasonable match of the tasting notes.

                            While this isn’t a blind taste test, and only a single experiment (I don’t want to waste loads of good beans), it’s clear that the density (and hence resistance to flow) doesn’t even out, and if it’s not level to start you can see this in the extraction. No comparison on flavour and I’ll definitely stick to my usual wdt level practice.

                              hornbyben While this isn’t a blind taste test, and only a single experiment (I don’t want to waste loads of good beans), it’s clear that the density (and hence resistance to flow) doesn’t even out, and if it’s not level to start you can see this in the extraction. No comparison on flavour and I’ll definitely stick to my usual wdt level practice.

                              I’m not saying that there isn’t a reason to level the bed before tamping. I used WDT and leveling before tamping for the espressos I made this morning, and found that to go more smoothly because of the leveling, and I don’t plan on changing my workflow..

                              I had a different experience than what you did. I think the main factor is that I tamped with a fair amount of force, which would mitigate any difference in density across the puck, which is predictable based on the reported properties of ground coffee. I do think that if you start with an uneven bed, and tamp with less pressure, an uneven density could result from that. Maybe the difference is that you’re using a self-leveling tamper, and I’m not.

                              Again, if I start with an unevenly distributed bed, and tamp with enough force, I can get to a puck that has even density across it. This is based on trying it, the feedback I got from poking at the puck with a toothpick, the fact that my extraction time did not decrease, and the taste of the espresso I got. I’m not saying that this is anywhere near best practice. This was mainly an exercise to better understand what’s happening when I go through the puck prep.

                                  wilburpan I can’t remember which spring I have in the tamper, but my gut says it’s probably the 15lb one, and certainly can’t be more than 30lb

                                      hornbyben That’s probably the difference in what we’re seeing, then. I don’t know how hard I was pushing, but it was probably more than 30 lb.

                                      So I wouldn’t say that we’re contradicting each other. To me it looks like our experiences with this are complementary.

                                        I uses a 2 slope leveller before tamping. If the grinds are level before using that I get straight into a single flow some of the time or 2 flows that merge pretty quickly.

                                        I did try a “3 slope” one and threw it away - 3 flows going to one and taking longer. This type doesn’t slope in the same way as the other.

                                        I use a ~13kg tamper setting and have done for ages. I’ve been thinking about increasing it.

                                        I also suspect I need to learn to keep the tamper level and forget the use of the leveller. The slopes compress the grinds. It’s set to do ~½ of the depth the tamper achieves, I can reduce that further. Next change. Reducing it from what I had used for a long time appears to help.