Gary, you are right in that there is a relationship between (type of beans ie density), fineness of grind and tamp. Did you also mention dose? Cant remember, I've just skimmed over your post quickly. Rule number one in my "book" (and probably Pinot's excellent reference book ;D) is you must fill the filter. "Fill" in this case meaning, not to the very top, but to the point where when you apply the group handle to the group, you just get a whisker of an imprint from the shower on the top of the tamped grinds. Then you can worry about fineness of grind & tamp. A heavier tamp pushes the grinds together more and results in a smaller puk, so filling the filter as stated abopve, is dependent on how hard you tamp. Make coffee. If it doesnt extract properly, and you have filled the filter as above and tamped "consistently" to an arbitrary pressure (say 15 kilos as measured when tamping on a bathroom scale), then the only variable than needs to be looked at at that point is the finess / coarseness of grind. Adjust as necessary & repeat until you get the extrction you want. It is finicky, you do get variation, do not become obsessed! ;D I am not familiar with the pressure guage on your model but it sounds very much like a "back pressure" gauge as also used on some other domestics. If this is the case, actually, its not a bad "tool" for novices. It will tell you what you want to know, as long as you have first filld the filter & tamped consistently as already noted above, because if (according to the gauge) you are over or underextracting, you only need tpo adjjst grind, repeat and wattch the guage. It is simply a mechanical device to tell novices exactly the same thing as experienced operatiors can tell you from just looking at the flow & sampling the brew. Having said all the above, I am an afficionado of overfilling the filter, tamping well ( even up to 20 kilos...who cares as lonmg as you are consistent in your own technique) and thereby setting a slightly more coarse grind. It gives a more rich, smoother coffee. No sugar for me. Others apparently do the same but beware, it (overfilling) can be hard on the equipment. Hope this helps, it's not that hard, and I repeat dont let it become an obsession! 😉 Regardz, FC.
