interesting (to me).
at the moment I am getting a rather unpleasant tang from my new to me machine. I would describe it as an overextracted undertemp tang, though I could be wrong.

this is a probably 10 year old very little used Cimbali Jr S/1 manual.

When I first received the machine (after I replaced the head gasket!!!) I could easily describe it as very easy to pull an excellent straight espresso shot.

What I have changed since then:
(1-3 in no particular order)
1. Insulated boiler and head.
2. cleaned stuck closed OPV and set it to 9.5 or so.
3. raised pstat heat a bunch (2-3 full turns on Sirai) (also cleaned Sirai membrane).
(also decalcified HX route and boiler route)
(also more attentive to keeping boiler level at MAX which would affect HX temp)

4. monitor heat on top of head - shooting for over 200F Seems to asymptote around 204.
5. new roast (1-3-07)(this roast is a tad oily - previous roast was not)(I had thought previous roast was underroasted) of the same beans, but darker than the last batch. (beans are GCC Brazil Vargem Grande Apr 2006 of 15 lb I got a while back)(roast is by SC/CO about 15 min)

Note: I essentially warm it up for an hour, (which gives me 200+ at the head), do a "big flush" (steam plus a few seconds), lock and load, pull double - (the head temp drops to somewhere in the low 190's).

Boiler runs at 240F.

Other than doing another roast, I wondered if anyone had thoughts about this.

Thanks!

pull a blank shot, let it cool, and taste it.

there could be some residue in the water path somewhere

2xlp wrote:pull a blank shot, let it cool, and taste it.

there could be some residue in the water path somewhere

Thanks - I just Cafizza-backflushed twice yesterday, thinking just that, but warming up now for your taste-test.

While waiting for it to come up to temp, I am looking at the result of insulation and trying to figure out why I am getting such a head temp drop, and thinking that by insulating, I have lowered the temp in the reservoir, relative to the HX. The stock machine only has a layer of fiberglas between the boiler and the reservoir. I wonder if I shouldn't go back to that...

I had hoped to make it less of a summer kitchen heater, and also less of an electricity consumer.

I guess an alternative would be to mod the HX feed tube to wrap around the boiler as had been done in other threads.

2xlp wrote:pull a blank shot, let it cool, and taste it.

there could be some residue in the water path somewhere

No tang. Tastes like boiled water with maybe the slightest hint of rubber.

However, I noticed that the OPV tube had white on the inside where it was in the reservoir water. So I disconnected the OPV tube and blew it out, then breathed in a tad through it and got a horrible smell/taste. So I left the OPV tube off and now have a little drain on the drip tray. Wonder what that's all about. (The stock unit does not have an OPV tube.)

In the meantime I pulled 90% of the insulation off and am now warming it up again and will pull another test in a bit.

Kristi wrote:No tang. Tastes like boiled water with maybe the slightest hint of rubber.

However, I noticed that the OPV tube had white on the inside where it was in the reservoir water. So I disconnected the OPV tube and blew it out, then breathed in a tad through it and got a horrible smell/taste. So I left the OPV tube off and now have a little drain on the drip tray. Wonder what that's all about. (The stock unit does not have an OPV tube.)

In the meantime I pulled 90% of the insulation off and am now warming it up again and will pull another test in a bit.

Well, plain water tastes better now. (I replaced all the water in the reservoir while I had it apart) The result of not recycling the OPV water?

Shot tastes very good now. Temp rises maybe .5 deg F during shot. Interesting to me, though, is that after the pull, the head temp (tc on top of head) drops from roughly 203 to 187F. Have no idea why it does that, and seems to take a long time to recover (like 15 minutes). Pstat seems to be functioning correctly as pressure stays between 1.15 and 1.3 (relative, as this gauge was broken. Repaired by yours truly but only functions in relative sense - not calibrated. Boiler temp is 240. May be that I should simply raise pstat.(?) New double gauge arrives tomorrow but I won't know until I get it whether I have the correct fittings to install it.)

So if inside of box is hotter, it works better. Or perhaps more accurately, it works as designed...

However, if this is a result of heating up water in the reservoir, how would/could this function on a plumbed machine?