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Thread: Sour shots from Gaggia Classic

  1. #1
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    Sour shots from Gaggia Classic

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have been happily making awesome coffees with my Classic and Rocky Combo for two and a half years now.

    I descale and clean it on a regular basis.

    I recently changed the group head seal and got good shots for about a week. But then they turned horribly sour, like undrinkable sour, even with milk.

    I have never cleaned out the rocky.

    Anyone with any ideas as to what is causing the sour shots? I have played around with the grind, the beans, descaled and cleaned. Is there anyway it is the grinder?

    cheers

  2. #2
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    Re: Sour shots from Gaggia Classic

    Is it possible that some of the descaling compound is stuck in the boiler or dispersion disc/showerscreen area?

    Try running some water though the steam wand into a cup and some water through the group into another cup and see if either tastes sour.

    If its only sour through the group, then try taking off the showerscreen and dispersion disc and see if water through the bare group still tastes sour - if not, give the showerscreen and dispersion disc a thorough scrub.

    If its sour through the steam wand as well as the group , then the boiler needs a more thorough rinse out.

    If neither the water from the steam wand nor the group are sour, then something is going on with the grind/beans.

    This is all assuming that the brew temp and shot time is fine.

    Greg


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    Re: Sour shots from Gaggia Classic

    Hi kaanage.

    I have run through 20 or 30 shots in the weeks before Xmas. I was flat out over Xmas and New Years so ended up buying a Kg of Ethiopian Yirgacheffe for plungers instead of trying to fix the Gaggia.

    Thanks for the suggestion regarding tasting the water from the group, I will give that a try and see if it narrows down the issue.

    I had another go at it this morning. The shot looked good - nice brown colour and good timing. I am a bit out of my routine as I havent used the Gaggia for 6 weeks or more! The crema looked good, but it did thin-out quickly. The odd thing I noticed today and on the weekend was that the espresso had very fine grinds in it. It looked as though some-one had sprinkled a quarter of a teaspoon of dirt in it. Very odd. The beans are five days after roast - 5 Senses of course!

    One thing I forgot to mention in the original post was that I had to pull the entire Gaggia apart to change the group head seal. I burred the shower screen screw, and ended up using an angle grinder and drill bit to take the head off the screw, then drilling out the screw from the dispersion disc.

    I was very careful whilst doing the above, but now it makes me wonder...

    I know about the OPV mod that you can do, and am keen to give it a go at a later date. Is there any other screws or knobs that I could have accidently knocked or twisted as I pulled it apart or put it back together?

    If memory serves me correctly, the coffees were tasting pretty similar before the Group Head gasket change, so I have assumed till this point that maintenance wasnt the cause of the off shots.....


    Thanks for your help with this! Its driving me bananas! :(

  4. #4
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    Re: Sour shots from Gaggia Classic

    Gaggias are pretty simple devices and what you have done wouldnt cause the issues you describe. Theres nothing much in the machine that could cause sour shots aside from temp if the shot times are ok.

    Id taste the water before exploring other avenues. Try water with the PF locked in too.

    5 days after roast is pretty fresh and the crema thinning out fast is typical of this - I assume this is not plunger roast as they tends to be a fair bit lighter (and hence more acidic) than espresso roasts.

    Did you see my post about the impact driver? Its bit a of a gorilla tool but not as much as machining a screw off.

    Greg

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 2F25252A252321440 link=1232707182/3#3 date=1233017827
    Gaggias are pretty simple devices and what you have done wouldnt cause the issues you describe. Theres nothing much in the machine that could cause sour shots aside from temp if the shot times are ok.

    Id taste the water before exploring other avenues. Try water with the PF locked in too.

    5 days after roast is pretty fresh and the crema thinning out fast is typical of this - I assume this is not plunger roast as they tends to be a fair bit lighter (and hence more acidic) than espresso roasts.

    Did you see my post about the impact driver? Its bit a of a gorilla tool but not as much as machining a screw off.

    Greg
    Cheers Greg.

    I might see if I can russle up a thermometer and get a basic temp read-out in the cup. Just to rule out something stupid like I didnt hook both heating elements up properly or something. Actually, thinking this through - its not really possible is it? The steaming is OK - a little bit weaker than it was when new, but it will still steam enough for two cups just fine. So there is no way there is only one element working is there?

    The coffee is not a plunger blend, it is their PM blend.

    I did see the post on the impact driver - which is a good idea. I have a Panasonic cordless drill which I had a go with - but the screw was too far gone at that stage. :(


    I will taste the water during lunch today and post back here.

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    Re: Sour shots from Gaggia Classic

    So what did the taste tests reveal?

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 0A00000F000604610 link=1232707182/5#5 date=1233059441
    So what did the taste tests reveal?

    The water tastes aweful!

    I tried it a few times, twice with the PF in, and then straight from the group, through the screen. It tasted very metalic. Even after running water through the group, and then four or five taste tests, there were still coffee grinds in the water. I let the machine warm up for half an hour or so, like I would normally.

    I will try and get the shower screen and water disperser out tonight, and see what the water tastes like straight from the boiler.


  8. #8
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    Re: Sour shots from Gaggia Classic

    Did you try tasting the water from the steam wand? (ie bypassing the whole group)

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 0903030C030507620 link=1232707182/7#7 date=1233104147
    Did you try tasting the water from the steam wand? (ie bypassing the whole group)
    No I didnt.

    I will give that a go in a while....

    Thanks for the suggestion.



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    Re: Sour shots from Gaggia Classic


    OK, I have tasted the water from the steam spout, and it tastes fine.

    I tasted the water from the group head again, and it definately has an off taste to it, but I let it go cold and tasted it again, and I think it tastes like very weak, cold coffee. So now I am not 100% certain what is going on.
    Hot, it tastes metalic and aweful, which I guess is the key.

    I will do a back-flush clean this weekend, and see if that makes any difference. I did one before and after I put the new group seal in, and I gave everything a good scrape and clean when I had it apart, so I would be surprised if it makes any difference.

    What do you think is the next move?

    Cheers

  11. #11
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    Re: Sour shots from Gaggia Classic

    Did you taste it with the showerscreen and dispersion disc removed?

    If this tastes OK, then give all those items (inc screw/bolts) a good scrub.

    If not, then the stuff must be in the solenoid/group and that could require disassembly to clean out :-/

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    Re: Sour shots from Gaggia Classic


    No, I havent removed the showerscreen or dispersion disc yet... was planning to this weekend.


    I was actually thinking about needing to pull it apart and clean it.

    Other posters on other forums tell some horror-stories about opening up their boilers to find a white sludge gumming up the works. I would hate this to be the case with mine :(


  13. #13
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    Re: Sour shots from Gaggia Classic

    The white stuff comes off easily enough with a brillo pad - dont worry if this is in your boiler. But since the taste is OK through the steam wand, your boiler is OK, even if a bit of the white stuff is in there (Ive always found it to be pretty solid).

    The white stuff is more a problem for the non-solenoid Gaggias as loose bits can jam in the group valve rubber seal and this will cause leaking through the group when in steam mode and can damage the seal which requires the whole valve assembly to be replaced (since you cant just buy the seal >:().

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    Re: Sour shots from Gaggia Classic



    Cheers Greg.

    I will pull of the shower screen etc this weekend and see how gunky it is.

    I am planning to put aside a good couple of hours to go through the machine like a fine tooth comb this weekend.


    The other thing I am going to do is pull apart the Rocky and give it a good clean. Then I am going to go back to basics and get the stop-watch out and time a few shots exactly, rather than relying on experience and the "One Cat-Dog, Two Cat-Dog" approach!

    Anything else I can do to narrow down what is causing this?

    Thanks very much for your help so far, it is very much appreciated!

  15. #15
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    Re: Sour shots from Gaggia Classic

    I think tasting without the screen/disc will be the final test before pulling the boiler off - luckily its straightforward and from what youve done before, it wont present any great challenge.

    But fingers crossed that it doesnt come to that!!!

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 545E5E515E585A3F0 link=1232707182/14#14 date=1233296755
    I think tasting without the screen/disc will be the final test before pulling the boiler off - luckily its straightforward and from what youve done before, it wont present any great challenge.

    But fingers crossed that it doesnt come to that!!!

    I was wondering about the boiler. I had heard it was easy, but I have never attempted it before.

    I will spend some time over the weekend playing, and report back here ASAP.

    Cheers and havagoodweekend!

    :) :) :) :) :)

  17. #17
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    Re: Sour shots from Gaggia Classic

    Did you manage to narrow down the source of the sourness?

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 5E54545B545250350 link=1232707182/16#16 date=1233703635
    Did you manage to narrow down the source of the sourness?

    Unfortunately not. Flat out with work at the moment, so put a few hours in over the weekend. Any spare time was spent with the wife and kids.

    I will hopefully have a more relaxed weekend coming up, so the Gaggia will be on top of the agenda! :) :)

  19. #19
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    Re: Sour shots from Gaggia Classic

    WOOHOO!

    Happy Dance!


    :) :) :) :) :) :) :) :) :) :) :) :) :) :)


    Its Business Time...

    I had my first espresso in months this morning, and it was awesome!

    WooHoo!

    Ahem

    Seriously now...


    I pulled apart both the Gaggia and Rocky over the weekend, and gave everything a good soak and clean.

    You should have seen the cr@p inside the Rocky..... and the smell! *My God! :( :( :(

    Rancid, disgusting oil and gunk through-out. *No wonder the coffee was tasting disgusting...

    So I cleaned everything, put it all back together and pulled a few shots.... *awesome!

    Thanks Kaanage... *you are very patient. *

    I cant tell you how happy I am... I can still taste the flat white I had this morning, and it is the nice, coffee flavour aftertaste, not a rancid, oily aftertaste.... :) :)

    I am a happy, happy boy!


    Cheers again!

    Spelunx

  20. #20
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    Re: Sour shots from Gaggia Classic

    Yay!! :D

    So has the taste of the water from the Gaggia group improved since the clean, as well?

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    Re: Sour shots from Gaggia Classic

    Quote Originally Posted by 565C5C535C5A583D0 link=1232707182/19#19 date=1234133418
    Yay!! :D

    So has the taste of the water from the Gaggia group improved since the clean, as well?

    Yep, slightly. It doesnt have the sour taste it did before, but it isnt exactly "Mountain Fresh". It has a more metalic taste to it now, which I guess is no big surprise, considering the amount of metal it passes over before it gets to the cup.


    Straight out of the boiler, no screen or dispersion disc, it tasted very similar. It did have some white flecks through it, so I might be time for another de-scale. After I get ahead with a few jobs around the house, I am planning to crack the boiler open and give it a clean, but that wont be for a few months yet!





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