# Pre 2015 Gaggia Classic Problem



## PaulF1990 (Dec 30, 2019)

Hi,

I'm hoping you can help me with an issue I am having with my new second hand pre 2015 Gaggia Classic Coffee Machine.

I bought the machine second hand and replaced the group head gasket and shower screen when I got it.

I have a basic burr grinder - De Longhi KG 79 which I always use on the finest setting.

For the first week, the machine was working well. 20 - 30 seconds with 16 - 18 grams of coffee for approx 50 - 60 ml. The shots tasted good.

For the last three days I have been unable to get the machine to pull a proper shot.

The water just runs through the puck and fills the cup in about ten seconds.

I have changed nothing from last week - same beans, same grinder setting, same tamp pressure.

I have tried reducing the pressure of the opv valve ( 360 degree turn anticlockwise) but this hasn't changed anything.

Any ideas what could be causing this?

Thanks in advance.

Paul


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## ArisP (Dec 17, 2019)

Hi Paul,

Just a quick guess, this sounds like stale beans/ coffee. Have you excluded that possibility?


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## PaulF1990 (Dec 30, 2019)

Hi,

No its a fresh bag.

Nothing has changed since last week, that's why I can't understand what the problem is.

Paul


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## ArisP (Dec 17, 2019)

PaulF1990 said:


> Hi,
> 
> No its a fresh bag.
> 
> ...


 When you say fresh bag, do you mean it is a different bag of the same beans from last week, or the same bag you were using last week?

In any case, try to grind finer until you achieve 20-30 sec pour. Beans change water content when exposed to air, and even "fresh" bean bags can be from different roasts.

Aim for grind setting wrt pour time. Grind setting alone means very little.


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## PaulF1990 (Dec 30, 2019)

Same bag and same beans. I have resealed the bag each time after taking beans out.

I am already grinding at the finest setting.

I feel like these is something different causing this. Last week 25 - 30 seconds per shot. This week it takes less than 10 seconds.


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## ArisP (Dec 17, 2019)

Ok, I see what you mean.

Other users can correct me here if I'm wrong, but the finest setting of this specific grinder is still not fine enough for proper espresso in an unpressurized basket. Are you using an unpressurized basket?


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## Michael87 (Sep 20, 2019)

The same packet of beans can become staler over time and that can reduce resistance. So you would gradually grind finer as beans get older. If your grinder doesn't allow this, then the flow will gradually speed up through the puck (this could happen rapidly, I don't know the fluid dynamics).

Failing that, maybe the OPV has become blocked. Can you test if it is still working (with a blanking disc in the portafilter and watching if anything comes out of the OPV pipe back into the resevior)?


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## PaulF1990 (Dec 30, 2019)

Hi,

I am using an unpressurised filter basket.

I understand the grinder is a basic model.

However, as I was saying the in the initial post - I was getting good shots using this grinder last week.

I don't understand what has changed suddenly to change pour duration from 25 - 30 seconds down to 10.


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## PaulF1990 (Dec 30, 2019)

Michael87 said:


> The same packet of beans can become staler over time and that can reduce resistance. So you would gradually grind finer as beans get older. If your grinder doesn't allow this, then the flow will gradually speed up through the puck (this could happen rapidly, I don't know the fluid dynamics).
> 
> Failing that, maybe the OPV has become blocked. Can you test if it is still working (with a blanking disc in the portafilter and watching if anything comes out of the OPV pipe back into the resevior)?


 Thanks for the reply. I don't have a blanking plate but I'll get one and try that.


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## ashcroc (Oct 28, 2016)

Turn your OPV back to where it was. Without a gauge, you're just guessing what it's set at anyway & counterintuitively a lower pressure needs a finer grind.


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## PaulF1990 (Dec 30, 2019)

ashcroc said:


> Turn your OPV back to where it was. Without a gauge, you're just guessing what it's set at anyway & counterintuitively a lower pressure needs a finer grind.


 Thanks - I'll do that.

However this problem started before I adjusted the OPV.


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## ashcroc (Oct 28, 2016)

PaulF1990 said:


> Thanks - I'll do that.
> 
> However this problem started before I adjusted the OPV.


Yeah. As previously mentioned, your grinder isn't really capable of going fine enough for espresso. You can hack it to grind finer but the adjustment will never be there so it'll always cause problems.


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## PaulF1990 (Dec 30, 2019)

ashcroc said:


> Yeah. As previously mentioned, your grinder isn't really capable of going fine enough for espresso. You can hack it to grind finer but the adjustment will never be there so it'll always cause problems.


 I understand that it is not a good grinder.

What I don't understand is what has changed in a day. Why was I consistently able to get pretty good shots last week and now, every shot I pull just pours through in less than ten seconds.


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## Hasi (Dec 27, 2017)

Hey up,

to understand your situation better, please elaborate what made your shots taste good before? Did you buy beans with taste notes written down somewhere? Did you get those in the cup?

Are they light, medium or dark roasted?

Do they come with a roasted on date?

Did you notice anything unusual on top of used puck? Like holes or one thick/on thin part?

How about the underside of the puck, can you spot colour differences in certain areas?

Did anything change about your pre-heating cycle? Does it give you these gushers all the time? How's your workflow/routine from getting up in the morning to drinking coffee?

Does pump sound differently now?

Also, you might want to remove shower screen as well as dispersion plate to look for residue build-up and blocked holes.


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## MartinB (May 8, 2011)

What beans are you using, what was the roast date?


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## MediumRoastSteam (Jul 7, 2015)

PaulF1990 said:


> I understand that it is not a good grinder.
> 
> What I don't understand is what has changed in a day. Why was I consistently able to get pretty good shots last week and now, every shot I pull just pours through in less than ten seconds.


Why do you think it's the machine to blame and not the grinder? It might have been that last week your grinder was fine, and now your grinder has broken/misaligned and is now giving you uneven and a coarser grind compared to last week. This is all assuming the coffee is fine and does not require a finer grind.

I know this is frustrating. But unless you have means of eliminating variables (I.e.: testing your grinder against another machine or using a different grinder with you existing machine) you'll never work this one out.


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## JonD (Dec 31, 2019)

I have the same setup and have also had mixed results.

I also came to the conclusion that out of the box that grinder doesnt grind fine enough. I did the "hack" (and then repeated the process another 5 or so times to perfect the setting) and now it's pretty much as good as it's going to get but of course I'm very limited in terms of adjustment so sometimes just can't dial it in accurately enough.

The other problem is that the grind is just not consistent enough and is prone to clumping... To cut a long story short a good grinder is now top of my shopping list.

If you haven't done the hack on the grinder I would recommend it (it might be good enough), but that said if I knew what I knew who before hacking it I would probably have returned the grinder and put the money towards a much better one.


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## PaulF1990 (Dec 30, 2019)

Thanks for all your replies.

I still haven't figured out why I managed to brew consistently good shots for a week with unpressurised filter baskets and my KG 79 grinder. I have tried every day for the last few days but every shot pours out in less than ten seconds.

The coffee beans I have been using are locally roasted in Ireland - Ariosa is the company. My bag was roasted during the second week of December.

The used coffee puck shows areas of different colour on the underside so I'm assuming the coffee is running through certain areas.

Gaggia service UK instructed me to equalise pressure in the boiler by switching on the coffee switch, opening the steam wand so water pours out and then closing it again before finally switching off the coffee switch. This also didn't work.

Looks like I'm going to have to revert to using the pressurised filter basket!

As regards the grinder 'hack' mentioned above, I think De Longhi must have modified this grinder since those videos and tutorials were released. I tried and followed the instructions exactly but was unsuccessful. Even if I move the wheel by one tooth, the burrs come into contact.

Maybe its time to buy a better grinder .....I like the look of the Baratza 270 but they are very expensive!!

One question for ashcroc - why does a lower pressure require a finer grind?

Thanks again all for your responses.


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## Michael87 (Sep 20, 2019)

I got some stale beans and my sage smart grinder pro at finest setting is still not able to stop it gushing out. It does sound like a combination of stale beans and grinder unable to get fine enough. My solution is to use fresh beans and look into upgrading grinder.


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## JonD (Dec 31, 2019)

PaulF1990 said:


> As regards the grinder 'hack' mentioned above, I think De Longhi must have modified this grinder since those videos and tutorials were released. I tried and followed the instructions exactly but was unsuccessful. Even if I move the wheel by one tooth, the burrs come into contact.


 I have to say that doesn't sound right, perhaps there is a fault with the grinder as well.

Maybe it's time to pop to your friendly local coffee shop and see if you can get some freshly ground beans and try that. It seems like there are too many variables at the moment what with the grinder and opv settings.

Jon


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## lake_m (Feb 4, 2017)

We played with one of these grinders at work for a bit. Those tiny ceramic burrs on the K79 go blunt in no time. Honestly, it's just not up to the job unless you use the pressurised basket.


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## PaulF1990 (Dec 30, 2019)

Further to above.

I have tried reverting to using the pressurized filter basket yesterday and this morning.

Even using this, the coffee is pouring through at a a ridiculously fast rate - it wasn't doing this a few weeks ago. In fact, the machine was almost struggling to push water through the coffee if I tamped too hard.

There is definitely an issue with my machine. A pressurized filter basket should allow brewing with the coffee from my grinder, even if it isn't up to grinding fine enough for unpressurized baskets.

Do OPV valves fail in the Gaggia Classic?


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## Hasi (Dec 27, 2017)

Yes, an OPV can fail as residue builds up.

You can easily check OPV functionality with a blind basket (or rubber insert). If you cannot grind fine enough to create some resistance in coffee puck.

Push up OPV drain tube (usually right one, if noone messed with your machine before and got them in the wrong way round) so that it sits above water level. Doing so, you can effortlessly spot any water coming out.

Don't go about disassembing/cleaning an OPV if you don't have a pressure gauge for re-calibration, though. There is at least one PF gauge floating around forum members - you might want to do a quick search for the respective thread.


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## ThePeginator (Dec 17, 2019)

I have one that can be posted / borrowed if needed.

Sent from my iPhone using Tapatalk


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