Ergh.. thanks, Dan. If you check the pic I posted up there of the regulator you can see the tee near the pump going to the pressure gauge like you guessed. Unfortunately I don't have the means to test the pressure at the grouphead, but I don't see how it would differ from the pressure at the pump since it is a closed system with (presumably) uniform pressure. If I had a portafilter with a pressure gauge perhaps I could check it.
I'll try to adjust my relief valve to 6 bar tomorrow and see what happens.

How much of a difference do different manufacturers' filter baskets make? The one I'm using came stock with the machine, and it holds about 17 grams of coffee with a level dose. That's a little larger than the 14 - 16 I've read all over the place for the commercial ones. Perhaps I should try to get a commercial filter basket (and a commercial portafilter while I'm at it) to see if maybe the distance between the holes on the bottom of the basket makes a difference? Just throwing out random ideas I've been thinking.

I've even gone so far as to examine the ground coffee that comes out of my grinder with a jeweler's loop, trying to get an idea of how uniform the grind really is. But since I have no reference, that was pretty useless. I'd give anything for a few hours with a Macap M4 or something, La Cimbali M32, and a few pounds of fresh beans just to see if there's actually something fundamentally wrong with my technique or if my equipment really is to blame. Hm.

I've had days where I could feel the zen. You know what I mean. It's those days where you are just in tune with all the variables and everything is perfect. Today was the opposite.

How about this. When I get the chance, I'm going to film my entire espresso ritual from start to finish, post it on here, and you tell me if you see something absurdly wrong with what I'm doing.
Oh, and about the pressure, well I guess unless my pressure gauge is wildly uncalibrated there's no way the pressure could be off. Usually it goes like this. Pump starts, gauge reads 0. After about 2 seconds it pops up to about 6 bar for 2 - 3 seconds until I see coffee, then hovers around 8 bar for the first 6 - 8 seconds of the extraction, then the relief valve cracks, which is set to about 9.5 bar when it reaches about 9 bar. Sounds about right to me. But whatever. I'll sleep on it and hopefully come up with an idea for tomorrow. Thanks a lot so far.

I've been told (in an espresso class, no less), that the definition of insanity is doing the exact same thing over and over again and to expect different results. I was tryng to froth milk on a 5-hole LM Linea steam wand.... my experience is a one-holed Silvia. The instructor might have been referring to me...

I would dial that OPV down to like 8 bar if you don't want to go so far as 6.... then like 7 or 6. If I wanted to get real drastic, I might unplumb that whole thing and go back to stock just to see... but I am crazy.

Here is a video I did for the Achille review from grind to finish

jesawdy wrote:I've been told (in an espresso class, no less), that the definition of insanity is doing the exact same thing over and over again and to expect different results.

Oh man, I've done that on more than one occasion. At least I know I'm insane though
Well, today was a little better. I pulled some halfway decent shots with less jets. I tried dosing a little more (+.3g), and I concentrated all my zen into making my tamp level, which was a problem I've been having since my perpendicular sense is pretty horrible. And also since my tamper sticks out a 1/2 inch from the top of the PF when it's fully compacted instead of being flush it's really hard to tell whether I'm level or not. I'm going to cut it down one of these days on the lathe.
Anyway I've had a cold and a stuffy nose for the past few days, so my sense of taste is not quite right, so I'm probably just going to take a break for a little while until I can taste the nuances of flavor again. Thanks all for the help so far.

edit: Thanks a lot for the video, cannonfodder. I really can't think of anything I'm doing that's not in line with what I've read for the last several months and what you did in the video, so I'll just have to wait until the gremlins go away and pull some more shots.

Personally, I think you have diagnosed your own problem in your original post.

I, for one, believe good espresso is a synergistic combination of lots of factors and even "minor" factors within the major catagories. The EXTENT to which each contribute to that ever elusive "godshot" can be debated ad infinitum.

See this: http://www.coffeeresearch.org/espresso/definitions.htm

I can't think of any downside to installing a PID vice the original click-style thermostat other than $. All you're doing is dramatically improving something the mfg had on the machine in the first place. Installing an OPV on a machine that, for whatever reason(s), didn't have one COULD BE questionable. There are ways to accomplish the same thing that an OPV accomplishes - some I am familar with - others not. At least one high end machine (Salvatore) has been reported to be without an OPV and certainly the majority of all lower end espresso machines lack this device.

It seems to me that everything started going downhill when you installed the "pressure mod" - so why not simply reverse that mod and start from there? When I look at your "pressure mod", I see lots and lots of teflon tape around those threads and some of that tape may have ended up in places it shouldn't.

Eric S.

HB wrote:Try removing the portafilter's basket retainer clip and tamp the basket on the countertop. Before lifting out the tamper, give the basket a quick twirl and it will be really obvious if the tamp is canted.

Yep, it's pretty consistently unlevel. Tried it a few times. I knew it would be, since the tamper sticks out of the basket so much that it's virtually impossible to get it to be level. I'll need to chuck it in the lathe and shave it down about 3/8" so it will be flush with the rim of the basket. The few tamps that I did manage to get level produced consistently better shots, just as I expected.

And Eric, that's a good point you brought up about the teflon. After I installed everything however I ran about two tanks full of water though the machine to make sure it was thoroughly flushed out, then disassembled the boiler again to make doubly sure there was no build up of anything I didn't want in there. So I'm about 99% sure that the teflon isn't a problem. I'm going to go recharge my ion exchanger (haha, that sounds so sci-fi) in a bit and see if that will help too.
About the pressure, removing the mod would really be more trouble than it's worth at this point. Instead, I tried to adjust the relief valve so that it wouldn't open at all during the shot so the machine would behave like it did before the installation. I think the problem with trying to decide whether or not the mod helped or hurted is that my technique is still not consistent enough to evaluate the machine's performance accurately. I think that that's biggest problem I'm having here, and I'm trying to blame it on the machine, when it's really just me.

I don't think there is a way to improve my technique consistency other than practice. So it'll take a few more pounds of beans until I can really decide. All I was trying to do with the mods was to make my machine do what it should have been doing in the first place, and do it consistently. As I've said before, now that I know what my temperature and pressure are, and that they are consistent, I can concentrate on improving my skills with less distraction. It's a never-ending journey, but it's fun, and that's what counts.

Assuming this is your machine,

http://www.partsguru.com/LaPavoni...itanaEspresso.html

take a look at parts MC112, MC112/1, and MC028. If I remember correctly, the water to the shower screen (and yours IS pristine?) flows through this check valve on the outside threading of part number MC028. Just throwing out some numbers here, the pump discharge pressure (as indicated by your pressure mod gage) may very well be 9.0 bar, but the pressure the puck is really seeing is a lot less than that because the threading of MC028 is acting, in essence, as an orifice.

So now, when you crank the regulating valve stem out (CCW) until it is loose, there should be zero flow in the flex line from the regulating valve back to the tank during a shot, i.e. the entire pump output is directed towards the puck. Your pressure gage may very well be in 12-13 bar territory. So now, assuming there are no teflon tape tidbits in/around MC028, you should be "back in business."

The above, of course, is how I read the design of the machine, i.e. it was never intended to have an OPV. BTW, removing MC028 typically requires a special precise wide blade screwdriver blade so, while you're cranking up that lathe . . .

I think it should be obvious that, in this particular case, I believe the problem lies in the machine side of the portafilter.

Good Luck,

Eric S.