Author Topic: Tuning a Gaggia consumer espresso machine for proper brew pressure & temperature  (Read 47317 times)

Tex

  • Guest
I normally just unscrew the barbed fitting and tap the center of it to 4-40 and then buy a 4-40 stainless screw... add a little teflon tape to the threads of the screw, problem solved.  I also put a nut on the end of the screw, but I don't think that it's necessary.

Great suggestion, but I don't want to invest in a tap set too; well, I want to, but I probably shouldn't.  I'm already getting a pressure kit and the adjustable OPV.

I'll keep that in mind though.  Think I like the teflon tape idea, just in case my coffee making habits have irreversibly been synced to having the hot water flow back into the reserve tank, then I can go back to the stock setup.

Irwin

The problem with the SPV is, it's a thief. It leaks, permitting the pressurized boiler to leak water back into the reservoir, and because it's an unregulated flow there's no way to adjust the OPV to compensate for it.

It's the same situation when you steaming - the SPV lets steam bypass the valve and flow to the reservoir.

It may not be the worst idea Gaggia ever had, but the Twin and the SPV are probably in a neck and neck race for that distinction.


petershek

  • Guest
Tex, thanks very much for the PID connection scheme.  I'm using a Gaggia Baby Dose.  Before reading your post here, I was trying to figure out how to control both brew/steam temperature with a single PID while keeping the functionality/lights on the original control panel.  Now you give me the answer: to fool the thermostat sensors of the machine!  Brilliant idea!

Regarding the pressure, I was told by a local tech guy to trim down the spring inside this T-shape plastic thing bit by bit and try out the pressure with a guage (what do you call that T-shape thing?)  It came to a success that I could use a sticker to mark the position for 8, 8.5, 9, 9.5 bar.  Now I'm using 9 bar settings.  Any comment on this modification and any drawbacks?





Tex

  • Guest
For all you Gaggia owners; remember to descale on at least a quarterly schedule - regardless of how hard or soft your tap water is.

For machines with a group valve (everything but Classic, Baby, OWC, and a few others), remove the internal piece (rightmost piece in picture), and using a straightened paper clip, ream out the hole in the bottom of the boiler controlled by the group valve.


roastingnerd

  • Guest
Boy, I didn't ralize how much trouble making decent espresso is when I bought what appears now to be a used Gaggia Espresso.   I thought it was a Classic because it had all the same controls only in different places.  I figured it was just an older model.  I don't make really decent espresso, so I figure some of the mods here might be needed.  But I am 80 now and my geek days are behind me.  Wonder if anyone could describe what might be needed for that machine so I could just show it to my son, next time he comes over.
Thanks.
Pete

Tex

  • Guest
Boy, I didn't ralize how much trouble making decent espresso is when I bought what appears now to be a used Gaggia Espresso.   I thought it was a Classic because it had all the same controls only in different places.  I figured it was just an older model.  I don't make really decent espresso, so I figure some of the mods here might be needed.  But I am 80 now and my geek days are behind me.  Wonder if anyone could describe what might be needed for that machine so I could just show it to my son, next time he comes over.
Thanks.
Pete


There are 3 mods I recommend;
1) Self Priming Valve mod: Gaggia designed the SPV so users wouldn't have to learn how to prime a boiler. Problem is, the blasted thing leaks and robs the boiler of brew & steam pressure. It's a very cheap & simple fix, and only the newer models of aluminum boiler machines need it.

2) Adjustable Over Pressure Valve: Conventional wisdom holds that espresso is best brewed at ~9 bar pressure. The pumps used in consumer espresso machines put out ~15 bar pressure. Some Gaggia models, like the Classic, have adjustable OPVs; and those models that don't have them can easily be retro-fitted with one for ~$50.

3) PID: Gaggia machines are equipped with mechanical thermostats that operate within a range of ~50 degrees. This is known as the dead-band, and simply put it sucks. CW holds that espresso should be brewed within a starting range of temperatures (196°F - 203°F), and a stock tstat just can't manage. A PID is a replacement for the stock tstat and can hold a beginning temp within 1°F. PID kits can be had for ~$150 and are fairly simple to install and come with excellent instructions.

I hope this helps and isn't too confusing? There's also a Gaggia users group (follow the link in my signature) with members who're glad to help. Here's a link that goes into these in more detail.

edited: It always helps if you include a picture of your machine.

Tex

  • Guest
About the 3-way valve in Classic & Baby models.

The 3-way valve relieves pressure in the brewhead after a shot. If you remove the portafilter of a non 3-way equipped machine, you might experience the thrill of a portafilter sneeze - wherein the pressurized contents of the brewhead blows back on the operator. Believe me, 200°F coffee is not fun!

So, if you have a Gaggia machine that's not equipped with a 3-way valve, let the pressure bleed off before removing the portafilter.

Tex

  • Guest
The 3-way valve relieves pressure in the brewhead after a shot.

Tex

  • Guest
A Gaggia Classic with the group pressure properly adjusted, pulls a nice lungo.


This machine does not have a PID.


Offline mp

  • Standard User
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  • Posts: 16800
  • Nothing like a nice shot!
Great looking shot there Robert ... as usual.

 :)
1-Cnter, 2-Bean, 3-Skin, 4-Parchmnt, 5-Pect, 6-Pu
lp, 7-Ski

Tex

  • Guest
Great looking shot there Robert ... as usual.

 :)

As grandpa used to say, "Even a blind pig finds an acorn now & then." That shot was more or less a fluke Mike - you can't always count on the bi-metallic thermostats in consumer machines to be accurate enough to make a shot like that.

Offline mp

  • Standard User
  • *****
  • Posts: 16800
  • Nothing like a nice shot!
Great looking shot there Robert ... as usual.

 :)

As grandpa used to say, "Even a blind pig finds an acorn now & then." That shot was more or less a fluke Mike - you can't always count on the bi-metallic thermostats in consumer machines to be accurate enough to make a shot like that.

I say the experience and knowledge of the puller certainly helped.

 :)
1-Cnter, 2-Bean, 3-Skin, 4-Parchmnt, 5-Pect, 6-Pu
lp, 7-Ski

roastingnerd

  • Guest
Tex: Wow that video WITHOUT a PID shows so much more crema than my  machine ever achieved.  I would be so happy to have mine working half that well.  At best, I got a quarter of an inch of crema on my espressos.  There must be something wrong with me or mine.
I tried the links to user groups stuff and I guess i'll need to join Yahoo.  Already have 3 internet accounts and I was hoping not to have to set another up.


Nerd

milowebailey

  • Guest
Tex: Wow that video WITHOUT a PID shows so much more crema than my  machine ever achieved.  I would be so happy to have mine working half that well.  At best, I got a quarter of an inch of crema on my espressos.  There must be something wrong with me or mine.
I tried the links to user groups stuff and I guess i'll need to join Yahoo.  Already have 3 internet accounts and I was hoping not to have to set another up.


Nerd
Nerd

Crema is not all in the machine.   The coffee, the age, the grind, and the espresso machine settings will determine the crema.

Tex

  • Guest
Howdy Nerd!
I look at crema volume the same way I look at other frou-frou; it's more about riding the bicycle than showing off what you can do with it.

Once you know your machine & grinder are in proper tune, then crema has more to do with bean freshness than anything else. And some beans make hardly any crema no matter how fresh they are.
« Last Edit: February 01, 2012, 01:00:15 PM by Tex »

Tex

  • Guest
Tex: Wow that video WITHOUT a PID shows so much more crema than my  machine ever achieved.  I would be so happy to have mine working half that well.  At best, I got a quarter of an inch of crema on my espressos.  There must be something wrong with me or mine.
I tried the links to user groups stuff and I guess i'll need to join Yahoo.  Already have 3 internet accounts and I was hoping not to have to set another up.


Nerd
Nerd

Crema is not all in the machine.   The coffee, the age, the grind, and the espresso machine settings will determine the crema.

But (There's always a butt around here, right?), brew temp does play into the color of the crema. Too low and it's blond; too high and it's more brown; just right and the crema is redder.