Debated whether I should have sent this as PM to Team HB members I've met in past vs. posting ; I decided on the latter as not to bother them.

The question being asked is am I pressure profiling (mainly) and temperature profiling (little as PID temp only drops by at most 3 degrees depending on how low I let pressure go on the gauge (whose accuracy is questionable) by opening the steam valve during brewing?

More accurate measure of pressure and temperature would be with this which is too much $$ for how little I would use it http://www.espressoparts.com/scace-2-es ... ure-device

What profiling am I using: Brew pressure profiling best practices - have any emerged yet?
Specifics (assuming 35 seconds from time E61 brew lever up to time E61 brew lever down): let the usual ramp of E61 occur then machine pressure gauge reads 9bar then once espresso flow seen from spout rough estimate lower pressure by one bar every ~ 8 seconds until finish at 6-7 bars (my coordination not very good and again I question accuracy of pressure gauge).
So far I pull ristrettos (e.g. brew ratios 60-65% and total volume drink 1.25 to 1.5 fl oz.) .

RESULTS: could be confirmation bias but I like the taste overall (not so flat taste but more 3 dimensional ---> sorry I need to learn SCAA/cupping vocabulary).
BEAN USED: Hawaii Isla Espresso (from Paradise Roasters; described as medium dark roast and hardly any acidity). PID set at 196F.

The true test will be Ethiopia Yirchacheffe bean, above "pressure profiling" and OE Pharos grinder. But will have to wait until next week as I left that grinder in Chicago at in-laws and need to get more Yirghacheffe as currently only one bag and it's Boss's for drip (Clever brew method).

BACKGROUND:
* machine is Alexia with PID (on the rare chance not known it is a E61 grouphead with single boiler dual use (SBDU) and has Watlow PID for brew and steam temperature (probe goes into boiler). I have 64mm flat burr grinder (Mazzer Super Jolly) and 68 mm conical burr grinder (Orphan Espresso Pharos).

* I do realize that pressure profiling is just another tool for barista and is NOT the end-all be all for brewing.
http://www.lamarzoccousa.com/blog/defin ... profiling/
I also realize I am doing something this machine was never intended to do. My favorite espresso beans are dark roasted one (e.g. Paradise Roasters Nuevo, Counter Culture Coffee La Forza (? current name)). Thus to have pressure profiling machine is not high up on my espresso needs. Barista training is.

* Where the heck did I get this idea ?
(1) uscfroadie's post on this thread What home espresso machines can do brew pressure profiling?


* Why the heck am I doing this?
(1) Curiosity and zero interest in buying lever machine or Slayer or GS/3 with Strada modification or Vesuvius. Also no access to lever outside of Chicago HB get togethers and local cafe.
(2) Reading this long thread , repeated advice there is pressure profiling helps mainly when brewing light roasted beans (or ones with more acidity).
Best espresso machine/grinder "in the cup" at budget of $3000, $6000, and $9000

Did you put a dimmer switch on the pump? Look forward to hearing ho it works with the Yrg

(for those wanting to skip my long-winded introduction, skip to the results in caps below)

No dimmer switch on pump as "Damnit Jim, I'm a doctor not an electrician! (in DeForest Kelley voice)" (sorry I could not resist ) and more importantly not willing to spend time. In case you did not see OP, I just lowered pressure (and subsequently temperature too) by releasing water through steam wand during brew cycle.

At time of OP (original post) I could not find Ethiopia Yirchacheffe (though admittedly hardly looking for it as it's for Boss drip (Clever brew) and at time she was consuming her Dunkin Doughnuts whole bean blend (don't even get me started on that)).

At time of post I did have Intelligentsia Ethiopia Kurimi roasted 11/6/2014, shipped to me 11/11/2014 and in deep freeze (-20F). Since Boss finally done with her Dunkin Doughnuts whole bean blend x 2 bags few days ago, it was time to thaw out the Intelly Ethiopia Kurimi and try my pressure profiling (and temp profiling less I.M.O.) experiment.

THE RESULTS
* each brew method done twice
*parameters: 196F on PID (don't have Scace E61 group head thermometer), Grinder is 68mm conical Burr (OE Pharos); Brew ratio 57% (each time 17.1grams bean to make 29.8grams drink). Pressure profile used is mentioned in OP (original post).

(1) with quasi pressure profiling---> acceptable acidity, and overall much more preferred to (2)
(2) NO quasi-pressure profiling ---> more acid , but still tolerable; not sink shot.
(3) for the hell of it, I used Super Jolly grinder, ground as fine as could before choked the E61, and it was more acidic. But it was NOT intolerable acidity like for Ethiopia Yirghacheffe in past (those were all sink shots). For those Yirghacheffe in past I also had neighbor sample and he agreed... his words were it is facial pucker inducing (from acidity).

Visually looking (and with roasted Yirchacheffe color only from memory (but I've bought literally >30 pounds over the years), the Kurimi looks darker. than Yirghacheffe but not as dark as Paradise Roasters Nuevo). I could not find Coffeereview.com review of it and subsequently Agtron number for it. It is no longer on Intelly website and I don't recall their roast level description. Google searches also yielded pages with no description of roast level for the Ethiopia Kirimi.

I was in Chicago yesterday visiting a good friend and stopped by Metropolis (on Granville) b.c. they usually have parking spot in lot. They were selling Ethiopia Yirghacheffe . Once Boss done with current Intelly Ethiopia Kurimi, I will try this experiment one more time. No time and not in mood today to dial in grinder for this Yirghacheffe.

Before I went to last Chicagoland HB meet #12 at Jim's I was seriously considering selling my Alexia and getting a lever like his Strega. But after using it and observing how fast drinks and discussing with Jim and Alan (who also owns Strega (PID'ed no less)), I found out it is not machine to use if need to make multiple drinks quickly. At least 2 times a year, I make 12-24 cappuccinos per day for in-laws. For those times, I borrow neighbor's Silvia to use as steamer. But for light roasted bean, it looks like a used lever is in my future. My main (and preferred) beans are the "comfort blends" like Paradise Roaster Classico and Nuevo. And from HB reading these roasts do not benefit from lever machines.

I put a dimmer on my vibe pump to do pressure profiling. What I've found using my e61 machine is that lower pressure means less flow and that means lower temperature of the water reaching the top of the puck. It makes sense because the e61 group head radiates heat and less heat in means the group head will settle at a lower temperature.

Curtis, a total novice question follow up from me. Do you have Scace thermometer or portafilter with temp probe to see how much temperature drops with the lower pressure? I ask because yes less pressure means less flow through group head . But I thought with that amount of brass it would take more than 30 seconds (brew time) for temperature to drop significantly.

I have an EricS thermometer in the group. I typically see an 8 or so degree fast rise (1-2 seconds) from idle temperature to max temperature. The temperature then drops about 4 degrees to steady state for a normal 30 second, 1.5 ounce shot. When I use the dimmer to reduce the pressure from 9 bar to 7 bar it will drop another degree within a few seconds then stabilizes. This is from memory since I don't have a temperature recorder.