# Gaggia Classic Pro problems & Adjustments



## Strumph (Aug 6, 2020)

Hi, I bought new Gaggia Classic Pro (after my Krups XP3440 which I mastered). I have Grinder Graef CM900.

BREW TEST:
I set it to Level 1 (it is not Level "Fine" which is "0"), and use double non-pressured basket and put
18g in-36g out for 33sek begin after pressed Switch (or 29sek after first drip).

Questions:
a) Where is my Crema? In all videos (like Whola Latte Love and others) see a LOT of crema in brewing. In my example when coffe brew, it looks wattery and BLACK. But you see on picture, there is a small amount of crema. Is that good?

  

  
unicorn face emojis

So, I know that I must adjust pressure, but on "WLL" videos showing example with Gaggia which is not moddified, how about that?

If I am so close to Time brewing, and have still 1 Level reserved on grinder, think that grinder will be fine.
Have calibrated tamper.
But Maybe you will tell me that I need to change coffee. I will.

b) For longer steaming, I ordered THIS Thermostat

Is that going on Gaggia new model too?


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## Blue_Cafe (Jun 22, 2020)

I have pretty much the same setup

(Classic and Graef 820)

1) I cannot use more than 14g in the basket else I get the puck hitting the screen.

2) I had to adjust the top burr on the grinder. It's not the best espresso grinder and you will get a load of posts telling you it's crap but it does grind ok and will do much finer. Mine is doing great at 6. At 5, I choke the shot.

3) I find a 14g basket is sensitive to the tamp and can knock out the grinder setting +/-1 Fortunately my dicky shoulder reliably clicks at about 20 lbs so it's good for me.(again you will get tamp disagreement but this is my experience)

4)I don't get too hung up on crema. Will is selling the beans and gear so take his comments as you see them. Some beans are better than others for crema (more CO2 from the roast process)

5) I'll disagree on messing with pressure on the Gaggia. You should get good results regardless.

6) Make sure to read up about the Gaggia quirks. It's a heavy block boiler and needs time to heat up. A flush n' go on a red light works well.

7. I would be slow to change the steam stat. You will cause secondary effects in the machine (else Gaggia would have used these from the get go!)

Try new beans and speak to @Black Cat Coffee


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## MrShades (Jul 29, 2009)

What coffee are you using? How old is it / when was it roasted?

What dose in and what yield out?

Yes the 155c steam stat will fit the Pro just fine. - and it should give you more steam power.

Dropping the max extraction pressure down to 9 bar may well help your crema - but I'd check other stuff first, so let us know the answers to the above about your coffee.

The Graef's aren't the best grinders and are stepped, which is a pain, but should pair reasonably well with a Classic and give you more than acceptable results - so your grinder and machine should be generally OK and I'd probably be looking at your coffee first if you really want more crema.

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## Strumph (Aug 6, 2020)

Blue_cafe and Mr Shades, thanks for answers.

I using Illy and Lavazza Espresso coffee. Don't know wnen was roasted.

Dose: 
In 18g.
Out 36g
33sek.
Coffee Illy.

I practicing Latte Art and that means less coffe crema is better. But I want just to know is my Gaggia working good.
I will try defferent coffee.

Most marks of coffee have "Crema" in their Name (like Lavazza Crema..). Is that means that coffe can create more crema or that name is not always exactly aright?


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## Blue_Cafe (Jun 22, 2020)

Go to your local roasters and buy some fresh beans. Ask for an espresso blend and you may get the crema you are looking for.

Crema is marketing bollox tbh. (go and watch J.Hoff's video on it  )


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## MrShades (Jul 29, 2009)

Buy some fresh beans... anything really but something that you KNOW was roasted in the last week or two.

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## Strumph (Aug 6, 2020)

That is impossible. I am from Europe and if I order from Europe, that is 1 or 2 week waiting for delivery.

I am not sure is that problem in coffee. On my last machine Krups, but on pressurised basket, I had almost same crema in all brands of coffee, lot of crema.

Today I tested pressurised basket on Gaggia half full (8g in basket) there is a little crema, but still, it is little. Look:  

Can you post me a link which coffees to buy from Europe? But with no too expensive shipping please.

Blue_Caffe. What is J.Hoff's video, where to find it?


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## Strumph (Aug 6, 2020)

Look now.

I bought Lavazza Super Crema, 17g. in, 34. out for 29 seconds.

Is that ok for pressure 13 bars? 🤭

I bought pressure guage and 2x12 bar spring which I will try cutt it down to 6 bar.

Also, good news that my grinder is adjustable (removing 2 screws inside and turn wheel for finer/coarser), which will give me more space to improvise.


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## MrShades (Jul 29, 2009)

I've got to ask - why on earth did you buy 2 x 12 bar springs, with the intention of "cutting them down" to 6 bar?

Why didn't you just get a standard OPV mod kit with a 9 bar, 6.5 bar and 5 bar spring in it?

You'll have serious problems trying to cut a spring down to 6 bar - as it'll be too short. The OPV kit has a 6.5 bar spring within it, but it's the same length as the standard spring.

You'll also end up with a spring that has a cut end - rather than the standard spring and the OPV mod kit springa that have parallel ends (like a normal spring does!)

I think you're heading for more trouble rather than less.... but good luck!


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## Strumph (Aug 6, 2020)

O hi, I think it is your sale page.
At first, Because I don't need all 3 springs..
Second: what if not that 6.5 bar like it is described?
Third: so I buyed two, one for reserve if I overcut first.
Fourth: At the end, it is cheaper then Set of 3 springs.

You are right, if I cut I will not have original hard edge of spring. I don't know is that important, but some peoples on YT made it.

Also, the ordered springs do not have cca 11 circles, they have only cca 7. It is not like original! Because of that will be hard to cut and find 6 bar (original easier to cut).


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## MrShades (Jul 29, 2009)

Strumph said:


> O hi, I think it is your sale page.
> At first, Because I don't need all 3 springs..
> Second: what if not that 6.5 bar like it is described?
> Third: so I buyed two, one for reserve if I overcut first.
> ...


 The springs that we supply are specified and designed to provide the OPV pressure relief that they are described and supplied as - so the 12bar spring is 12 bar. It's not specified as a spring that you can cut down to whatever pressure you want to achieve.

If you intended to have 6bar then you'll find this pretty difficult to achieve by cutting down any 12 bar spring, as it'll end up too short to work effectively and keep the valve cap closed in normal use or when steaming. Our 6.5bar spring is the same length as the original spring - 25mm. You'll end up with a cutdown spring around 15mm, which isn't going to work.

Yes - it's cheaper to buy one or even two 12 bar springs - but entirely the wrong thing to do if your intention is to cut them down to try and achieve 6 bar. If you'd asked then I could have told you this - as I don't like seeing people waste money.

Good luck anyway - and I hope you can do what you intended.


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## Blue_Cafe (Jun 22, 2020)

Strumph said:


> O hi, I think it is your sale page.
> At first, Because I don't need all 3 springs..
> Second: what if not that 6.5 bar like it is described?
> Third: so I buyed two, one for reserve if I overcut first.
> ...


 Springs are funny things. Whilst one may think they are simple, they are in fact, complex and when used in a safety valve, that complexity is critical to the performance of the safety valve and, the safety of the device it's protecting.

In the later Gaggia classics, these safety valves are not 12 bar. They are 16-18 bar in the V2 and whilst I can't find any data for the pro, the same set up is used and videos of pressure tests show that the safety valve is set at a higher max P than the pump.

This then, tells you that these valves are not designed for constant use. They are emergency use only for boiler overpressure.

The difference in spring design is going to give a different response during any overpressure. A spring with less coils is going to be stiffer, causing potential back pressure problems if opening in an emergency.

If it were me, I would leave it well alone to do its job should I ever need it to do so.

Fortunately, on the GCP, iianm, you can add a second Safety valve which was commonly referred to as the OPV from the original V1. Just swap out the group inlet valve and use that to set the max system pressure.

There is a YT video of this.

Just remember that you are not only changing the set point of the safety valve by changing its internal spring from 16 bar to 9 bar but you are changing its function from a passive to an active valve.

Best of luck with your decision!


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## Strumph (Aug 6, 2020)

Ok.

I only know that new model have 13-14 bars. Not 18.










I will return and change it to set of 3 springs.


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## Blue_Cafe (Jun 22, 2020)

Strumph said:


> Ok.
> 
> I only know that new model have 13-14 bars. Not 18.


 Correct.

The pump stalls at 15bara


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## Strumph (Aug 6, 2020)

> MrShades:
> 
> Our6.5bar spring is the same length as the original spring - 25mm.


 All time I talking about 6, but I want cut it to* 9 bars*! Like others do. It is mistake, sorry. But this is not change what you said about don't cut.👍🏻


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## Strumph (Aug 6, 2020)

I got big crema ! 😃

Now. It seems that for *PID* must remove out thermostat. I don't want that.

But, I want only see boiler temperature (for steaming and brew water, right?).

Can I do that without removing thermostat (or any parts) out, like only put sensor from side of boiler to show me temperature?

Temp. sensor


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## MrShades (Jul 29, 2009)

Strumph said:


> I got big crema !
> Now. It seems that for *PID* must remove out thermostat. I don't want that.
> But, I want only see boiler temperature (for steaming and brew water, right?).
> Can I do that without removing thermostat (or any parts) out, like only put sensor from side of boiler to show me temperature?
> Temp. sensor


Good... well done!

Why don't you want to remove the thermostats and add a PID?

If you just want to see the temperature then you should be able to use that thermometer that you linked to in order to give you a good idea of what it is... but a small amount of thermal paste on the side facing the boiler and then strap it firmly to the boiler with a large jubilee clip.

Be aware that you want the boiler to be around 8c-10c hotter than the brew water.

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## Blue_Cafe (Jun 22, 2020)

Strumph said:


> I got big crema ! 😃
> 
> Now. It seems that for *PID* must remove out thermostat. I don't want that.
> 
> ...


 I intend to do this as well 

I just haven't got round to it yet.


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## Strumph (Aug 6, 2020)

MrShades said:


> Good... well done!
> 
> Why don't you want to remove the thermostats and add a PID?
> 
> Tapatalk


 Because I bought a new one (155c), which must replace it.

Instead counting a seconds, Temp. sensore will be more useful, right? And hope it will working to show temp. from outside of boiler. Not matter is it accurate, just consistency every time.


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## MrShades (Jul 29, 2009)

Strumph said:


> Because I bought a new one (155c), which must replace it.
> 
> Instead counting a seconds, Temp. sensore will be more useful, right? And hope it will working to show temp. from outside of boiler. Not matter is it accurate, just consistency every time.


 Well, you'll see what the metal temp is - but because the water is inside the boiler and the boiler temp constantly cycles up and down under thermostatic control, the actual water temp that comes out will be more like an average of the values that you see over time. So if you see 110c max and 95c min, you'll probably find that the water is going to be closer to 102.5 (minus around 8-10c for the offset)... so circa 92-94c. If the elements are on, this will be rising, and if they are off it'll be falling. It's not really going to help hugely with the actual temp of the brew water.

The huge benefit of a PID is that it keeps the boiler at a constant temperature, so over a short period of time you know that the water within it is also at that temperature. It doesn't cycle up and down - it's constant. With thermostatic control you have the temperature cycle and the fact that the water isn't reacting to the metal temp very quickly.


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## Strumph (Aug 6, 2020)

Oh now understand. No too much help of this sensor.. And PID holding water stable. 
So I assume that temp. can be adjusted by myself?
And what about steaming wth PID, is there just need to adjust higher temp. then brew?
How do I know that I not distroy a boiler with set overheat temp. with PID?


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## MrShades (Jul 29, 2009)

With a PID you can adjust both the brew temperature and the steam temperature - so you can set the brew temp to be 94.0c (around 102-104 at the boiler) and the steam temp to be 140.0c (around 148-150 at the boiler) - or whatever other temperatures you want to use for brew and steam - and the you just use the machine as normal, pressing the brew button and steam button as you normally would. You adjust thge temperatures yourself with some simple button pressing.

If you are crazy, you can always set the PID to a temperature that will kill the thermal fuse on the machine - so you could set the steam temp to 180c if you really wanted to, and the thermal fuse will blow. I won't destroy the boiler, it'll just blow the thermal safety fuse.


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## El carajillo (Mar 16, 2013)

MrShades said:


> With a PID you can adjust both the brew temperature and the steam temperature - so you can set the brew temp to be 94.0c (around 102-104 at the boiler) and the steam temp to be 140.0c (around 148-150 at the boiler) - or whatever other temperatures you want to use for brew and steam - and the you just use the machine as normal, pressing the brew button and steam button as you normally would. You adjust thge temperatures yourself with some simple button pressing.
> 
> If you are crazy, you can always set the PID to a temperature that will kill the thermal fuse on the machine - so you could set the steam temp to 180c if you really wanted to, and the thermal fuse will blow. I won't destroy the boiler, it'll just blow the thermal safety fuse.


 You have the patience of Jobe  :exit:


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## Strumph (Aug 6, 2020)

El carajillo said:


> You have the patience of Jobe  :exit:


 So what? He want just help..

I see. I assume that thermostat get temperature on his screw, can I get more precisely messaure if set sensor wire around that screw?


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## MrShades (Jul 29, 2009)

No, that's not your problem - your problem is the thermostat and the fact that the temperature is constantly going up and down.

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## Andy Lewis (Sep 6, 2020)

FWIW...

The thermostat is a simple on / off temperature controlled switch (with some inherent hysteresis). Couple this with thermal impact (i.e. a time delay for heat dispersal) then such a system will inherently 'hunt' for any given temperature - this thermal model must also include considerations for the power available and the amount of water one wishes to heat (e.g. not enough power and too much water one would never reach a desired temperature etc).

Such a simple system as used in 'classic' coffee machines can be improved on of course. There is nothing inherently 'wrong' with this system but it is a bit hit and miss and from my very little understanding of coffee brewing thus far, that which people seek is a precise repeatability: Grind size, pressure, water quality, temperature etc. If one can initially control all these elements then one can experiment and find the best setting for each. Once the best settings have been found (for the ultimate coffee), then those settings can be repeated again and again for the same results. For a thermostatic control system which is hunting between say 90°C and 105°C to achieve a desired temperature of roughly 93°C-ish will be pretty random (based on when you hit that coffee making switch).

So PID: First thing to note is that this introduces a separate temperature monitor and a separate switch (a thermostat is BOTH). The boiler heating element is now controlled by the PID via an external special solid state switch which is able to switch on & off far quicker that a thermostat and is thus employed as PWM control (I think). A thermistor or thermocouple is now used in place of the existing thermostat to monitor the temperature of the water in a classic feedback system, with PID algorithms used to reach any given target temperature quickly and without oscillating (hunting). The thermocouple can be placed anywhere on the boiler, hence the existing thermostat need not be removed.

FWIW, I would not use this for the steam temperature - at the mo' I can see little point.

A


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## Strumph (Aug 6, 2020)

Today I changed opv to 9.5 bars.. I created video before and after upgrade, but there are not visible changes on eye... Is that good?

I thought that coffee will flows slower then before, and that I will have to change grinder to coarser, but that not happened. It seems that flow is same like before, and grind settings stay same on my tests. Tell me is that good?

Difference in coffee taste not found yet, but later maybe will.


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## El carajillo (Mar 16, 2013)

You have changed the pressure at which the OPV valve releases the excess pressure. This does not change the flow rate, this is governed by pump flow rate.

You have reduced the maximum pressure applied to the puck BEFORE the OPV opens. Do you know what the pressure was set to before you adjusted it ?


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## Strumph (Aug 6, 2020)

Before was set on 13-14 bar. Not sure exactly because my guage is maximum 12.5 bar.

Good to know that flow not changing. 👍🏻

I think I see difference in single shot now, it is more foam then before.


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