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Thread: Gaggia Classic - tiny white flakes in water after de scaling

  1. #1
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    Gaggia Classic - tiny white flakes in water after de scaling

    Hey guys, been lurking for a while and this is my first post so go easy on me I had a laugh.

    Purchased a Gaggia Classic second hand off Gumtree a couple of months ago and also purchased a M2M grinder from K Bean off here.

    To my issue. I have recently given the Gaggia Classic a bit of a "service" removing and cleaning group head, shower screen, replacing group seal and backflushing machine.

    Today, I decided to send scale with Caffeto descaler, I followed the instructions of development scaling from the Gaggia User group forums but after flushing filter water through the machine a total of 4 times now, it seems tiny white flakes appear in the water.

    I have no idea of these white flakes were an issue before descaling as it's not something I ever paid attention to. I thought after flushing the machine completely multiple times that the white flakes would go away but it seems they still appear in the water.

    Is this something to worry about? The water appears clear it's just the very "top" of the water that has these white, almost milky flakes in it.

    I will try to upload pictures when I have a chance. Hopefully I've explained the issue clearly.

    Cheers,

    Luke

  2. #2
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    Yep, that's scale. Often Gaggia Classics go for a lifetime without being descaled, so if you got it second hand this may be the first time it has occurred!
    I'm a big fan of opening the boiler and manually descaling with a brass brush on a Dremel rotory tool, but this isn't for everyone.
    Try another descale to dissolve the buildup?

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    Yeah figured it was scale as I was fairly certain I would have gotten rid of any residual descaler from flushing the tank empty so many times.

    I would be surprised if the machine wasn't looked after as it was previously owned by a segafredo coffee servicer, but judging by how dirty the group head was and how dried out the group seal was, I'm starting to think maybe it wasn't so looked after, after all.

    Any guides you recommend for opening up the boiler and doing a manual descale? I hear working on the Classic is reliably simple, so I'd be willing to give it a crack f it's possible it will help.

    I will try another descale tonight when I get home from work and see if that helps.

    Thank you timmyj21

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    Update.

    Descaled machine again but scale still is in the water, and small black grit as well. Looks like I may have to take the boiler out and descale

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    Bummer. There are heaps of guides on how to go about dismantling a Classic.
    Common sticking points:
    - label the wires out of the main switch! I go from 1 to 10 on the wires down the 3 switch columns.
    - boiler bolts corroded and stuck. Can be really tricky to remove and requires the use of 4-letter words. Get back to me if you need advice!
    - open up the solenoid valve and descale the bottom part, getting access to the tiny holes inside. This is a common blockage point.
    Good luck!
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    Quote Originally Posted by timmyjj21 View Post
    Bummer. There are heaps of guides on how to go about dismantling a Classic.
    Common sticking points:
    - label the wires out of the main switch! I go from 1 to 10 on the wires down the 3 switch columns.
    - boiler bolts corroded and stuck. Can be really tricky to remove and requires the use of 4-letter words. Get back to me if you need advice!
    - open up the solenoid valve and descale the bottom part, getting access to the tiny holes inside. This is a common blockage point.
    Good luck!


    Labelling - +1. ALWAYS label any complex wiring.

    The bolts - I recommend penetrene (the bottle, not the spray). It will free anything if you just put a drop on every bolt once a day until they free. Worst case - 3 weeks, mostly days 1 to 3. The classic engineer's corrosion remover for 50+ years. A large bottle will last many years, and eyedroppers are cheap...

    Solenoid - +1 - that is all that a friend's one needed.

    The dremel idea is only needed if CLR fails (mind you, rinse CLR off very, very thoroughly - it tends to stay around).

    Good luck


    TampIt
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    So pulled everything out, soaked all internal parts that weren't electrical in Caffeto machine cleaner. Over all the internals seemed to be in good condition. Some scale on the temperature plugs, and a small amount of scale on the edge of the boiler on the inside. Let everything including boiler and group assembly sit in Caffeto for 20min then scrubbed with a brass wire brush.

    With the small amount of scale found, I'm thinking maybe scale in the machine wasn't the issue after all. Will re assemble tomorrow and see how it goes.

    Also, the boiler still has slight blackish corrosion on the outside rim where the seal sits, is it necessary to dermal it out as scrubbing it will not remove it.



    The only real scale found on boiler


    After 20min soak and heavy scrubbing with wire brush

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    Depends if there is any deep pitting to the boiler face. If it is all smooth, leave it, but if there are little holes where the seal make contact I would use a bit of wet and dry sandpaper to smooth and polish flat.

    If you think you may have got the heating element terminals damp, I would also put the entire boiler in a cool oven for an hour to ensure it is completely dry. The element insulator absorbs water and will short out.

    Good looking boiler by the way, you shouldn't need to do this for another 10 years.
    While in there, why don't you upgrade the boiler bolts to stainless steel, replace that 107 brew thermostat with a Pt100 thermocouple, add on a PID and shot timer....maybe even a preheater?

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    Hmmmm...you mentioned scale on the temperature plugs. From the photo I think you might be referring to the thermal paste to allow good heat transfer? Important to replace that!

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    Quote Originally Posted by timmyjj21 View Post
    Hmmmm...you mentioned scale on the temperature plugs. From the photo I think you might be referring to the thermal paste to allow good heat transfer? Important to replace that!

    Oh I'm an idiot, so that's thermal paste and not scale I had a laugh. Any idea where I get thermal paste on a Sunday? Looks like Bunnings don't stock it as couldn't find any on their website.

    Thought about doing PID but really don't want to spend more on machine as will upgrade to a HX in a couple of years plus the girlfriend will complain she needs her coffee so it needs to be put together asap I had a laugh

    I will put the boiler in the oven as those connections would have got wet, I've left them to dry over night but will put in the oven any way as an extra precaution.

    I'm just worried now that scale wasn't the issue, as the only bit of scale found was that small bit on the edge of the boiler rim. Hmm..

  11. #11
    Senior Member LeroyC's Avatar
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    Looking good. The white flakes will definitely be scale and/or descale product that hasn't quite dissolved. The Caffeto descaler is a powder right? I've moved to liquid descalers now, much better. Caffeto machine detergent is good stuff for backflushing and soaking portafilters and baskets though. Even though the boiler looks clear you probably did dislodge a little scale that migrated to the group head and got stuck. It would've come out eventually, but it may also have ended up in the 3-way so it's good that you've done a full strip down.
    Make sure you manually clean everything while you've got it apart: the group head including removing the dispersion screen, the 3-way as per Timmy's instructions above and everything else. Definitely give the boiler seal face a light rub down with wet or dry and make sure you replace that thermal paste on the thermostats. Not sure where you'll find any sorry, Jaycar maybe?
    Once it's all back together check your flow rate following the instructions on the GUG. And use it in a way that avoids scale build up - always fill with filtered water and always flush the machine after each use to ensure the boiler is full and the water in it isn't too high in mineral concentration.
    As far as mods go in the future I recommend an OPV adjustment and steam wand upgrade as a bare minimum. I have a portafilter pressure gauge you can borrow to do this if you like, just send me a PM if you're interested. (Although if it was owned by a tech these may have been done already?). Also I highly recommend replacing the dispersion screen with a brass one. These can be bought for a reasonable price from a U.K. based online seller. Other than that just learn how to trick the boiler heater for consistent brew temps and continuous steam......and enjoy.

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    Quote Originally Posted by LeroyC View Post
    Looking good. The white flakes will definitely be scale and/or descale product that hasn't quite dissolved. The Caffeto descaler is a powder right? I've moved to liquid descalers now, much better. Caffeto machine detergent is good stuff for backflushing and soaking portafilters and baskets though. Even though the boiler looks clear you probably did dislodge a little scale that migrated to the group head and got stuck. It would've come out eventually, but it may also have ended up in the 3-way so it's good that you've done a full strip down.
    Make sure you manually clean everything while you've got it apart: the group head including removing the dispersion screen, the 3-way as per Timmy's instructions above and everything else. Definitely give the boiler seal face a light rub down with wet or dry and make sure you replace that thermal paste on the thermostats. Not sure where you'll find any sorry, Jaycar maybe?
    Once it's all back together check your flow rate following the instructions on the GUG. And use it in a way that avoids scale build up - always fill with filtered water and always flush the machine after each use to ensure the boiler is full and the water in it isn't too high in mineral concentration.
    As far as mods go in the future I recommend an OPV adjustment and steam wand upgrade as a bare minimum. I have a portafilter pressure gauge you can borrow to do this if you like, just send me a PM if you're interested. (Although if it was owned by a tech these may have been done already?). Also I highly recommend replacing the dispersion screen with a brass one. These can be bought for a reasonable price from a U.K. based online seller. Other than that just learn how to trick the boiler heater for consistent brew temps and continuous steam......and enjoy.
    I was almost certain it was scale and not descale product as I had flushed about 4 or so full tanks of fresh water and still getting flakes and cloudiness in the water.

    Yes, both the descaler and espresso machine cleaner are both powders, I'll make sure to give the liquid a try from now on; thank you for that.

    Yeah have manually cleaned everything, but I'm thinking now should I soak stuff in just plain water to ensure any excess cleaning solution is removed from the parts?

    Have removed all parts of the group including the shower screen and plate as before pulling the machine apart I replaced the group head gasket and soaked and cleaned everything. Jay car ended up having thermal paste, so will be putting that on the connections. Sorry for the noobness, what is a GUG? haha

    I allways use filtered water out of my Brita Jug but I have heard the Brita filters can cause the water to be to soft? I may check my PH levels in the future with a testing kit. The silvia wand was already upgraded before buying the machine, so there's a chance the OPV was already done but I have no way of testing due to not having a pressure guage, I'd borrow yours but it seems you are in New Zealand?

    Will look into the brass shower screen.

    Thanks for all the help guys, friendly bunch!

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    Quote Originally Posted by timmyjj21 View Post
    Depends if there is any deep pitting to the boiler face. If it is all smooth, leave it, but if there are little holes where the seal make contact I would use a bit of wet and dry sandpaper to smooth and polish flat.

    If you think you may have got the heating element terminals damp, I would also put the entire boiler in a cool oven for an hour to ensure it is completely dry. The element insulator absorbs water and will short out.

    Good looking boiler by the way, you shouldn't need to do this for another 10 years.
    While in there, why don't you upgrade the boiler bolts to stainless steel, replace that 107 brew thermostat with a Pt100 thermocouple, add on a PID and shot timer....maybe even a preheater?

    Thanks for all the help mate.

    Going to put boiler in oven now, by cool oven do you mean to just put it on the oven with no heat? Or put oven on "keep warm" setting and leave it in their for an hour?

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    100 to 120 is fine and within normal operating temperature of the boiler.

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    Brita filters don't do much with the water hardness unfortunately, but it's better than nothing. It's what I use.
    GUG = Gaggia Users Group.
    If you are in Melbourne I have a pressure gauge portafilter you can use to check the OPV, otherwise there is the water debit flow rate method described on GUG.

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    Quote Originally Posted by timmyjj21 View Post
    otherwise there is the water debit flow rate method described on GUG.
    Which can be a Clayton's way of checking what the OPV is set to, but I wouldn't recommend adjusting the OPV using this method. There's a few people that have claimed that if you turn the OPV adjustment screw 270deg you get it to about 10bar, but others have shown this method to be incredibly flawed as it gives varying results.
    Borrow Timmy's PF gauge if you can Mrsr20.
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    Okay, so today I reassembled everything and out machine back together.


    Rinsed through three full takes of filtered water through the machine in hopes of seeing no contaminants in the water, but as you can see the whole cleaning process seems to have been a waste of time which is disappointing and leaving me scratching my head as to what could be causing this.


    Everything else works as intended, pulled a nice shot but I seem to be getting a soggy puck sometimes that's getting stuck to the group head.

  18. #18
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    Flush, flush, flush and when you think you've flushed enough...


    Java "Flush some more!" phile
    Toys! I must have new toys!!!

  19. #19
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    Quote Originally Posted by Mrsr20 View Post
    Okay, so today I reassembled everything and out machine back together.


    Rinsed through three full takes of filtered water through the machine in hopes of seeing no contaminants in the water, but as you can see the whole cleaning process seems to have been a waste of time which is disappointing and leaving me scratching my head as to what could be causing this.


    Everything else works as intended, pulled a nice shot but I seem to be getting a soggy puck sometimes that's getting stuck to the group head.
    Right. Firstly, don't stress. The manual clean that you did definitely wasn't a waste of time. It achieved two things - it eliminated the boiler and group assembly as the source of the problem, and it also let you see the condition of the inside of your boiler. Which happily turned out to be really good.
    So if I think about your first post you said that you'd run a descale through the machine. I take it that you mixed up a solution and poured it into the water reservoir then ran it through the machine? If that's right then I think the white stuff might be coming from somewhere upstream of everything that you cleaned this weekend, which is pretty much just the pump. The pump is less prone to scale problems as it doesn't go through the constant heating and cooling of the rest of the machine, but it can still experience scale. In fact I know of people that have pulled apart Ulka pumps and found decent amounts of scale in their causing issues. If that's the case then flushing is your only solution. You could try flushing with warm water in the tank, but just be very careful its warm and not hot as these pumps are only rated to about 45-50deg or something like that. Whatever it is they don't like very hot water, so take care.
    Finally the soggy puck probably isn't anything to worry about. The relative 'wetness' of your puck is usually due to your grind-dose-tamp rather than anything the machine is doing. The whole 'you want a nice dry puck' is an old wives tale and isn't something to aim for. Although if you have a soggy puck that's sometimes sticking to the shower screen this indicates to me that you're overdosing. It's easy to overdose a Classic and I highly recommend avoiding it as it just ends up sending lots of coffee back up the line into the group and 3-way. If you're using Gaggia double baskets you want a dose of about 15g in there, maybe 16g at the most. If this gives you a fast running extraction then grind finer, but don't change the dose.
    Anyway, how does the coffee taste? If it tastes alright then you're doing fine and just need a few little tweaks here and there.
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    Thanks mate. Yeah I know it wasn't a complete waste of time, was just a bit of effort and confirmed my fears that it wasn't going to fix the scale in the water. These things are usually a process of elimination though.

    Yes, I ran Cafetto descaler through the machine, 1tbs to one liter of water as directed.

    I'm not following you completely in relation to flushing the pump. You say to flush with warm water in the tank, but isn't this what I have been doing? Since reassembling the machine, I have warmed the machine up and flushed approx three tanks worth of filtered water out of the machine.

    I'm still at a point where I'm trying to "dial" in my shots, as I have only had the M2M for about a week. I've been playing around with different settings, I have been overdosing for sure it seems as I have been putting 17-20g. I find when dosing on the smaller side of things, I do get an extraction that's too fast and haven't been able to go finer as the coffee tends to "clump" on the finer setting.

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    And it was definitely descaler? Not cafetto machine cleaner?

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    Quote Originally Posted by timmyjj21 View Post
    And it was definitely descaler? Not cafetto machine cleaner?

    I backflushed the machine with Cafetto Expresso cleaner twice prior to descaling with Cafetto Descaler.

    Once I did the pull down of the machine after finding scale on the water, I soaked all parts in Cafetto Expresso Cleaner prior to re assembly.

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    Ahhhh.... That really shouldn't go inside the boiler or components. It's just for backflushing. This is where the suds are coming from. Needs and amazingly thorough rinse.

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    The guide that I followed said to either use an Expresso cleaner or citric acid for the parts, so I just followed that.

    The scale in the water was showing in the water before I took apart the machine and soaked parts in Expresso cleaner.

    Prior to pulling machine apart, all that I had done was backflush with Expresso Cleaner and Descaling with descaler solution.

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    Scale particles still present after a descale is pretty common if there is a lot present, as all the bits become loose but may not fully dissolve. There is a high risk of the solenoid getting blocked, so a complete teardown is a good idea with an unknown machine. Your current picture now looks more like froth on the surface as opposed to sediment/scale, so I'm thinking it is more the buckflush/cleaner solution still in the system. If the boiler was virtually clear of scale, then the pump is less likely to be a source (hopefully).
    Coffee machine cleaner is best for external parts that can be easily rinsed: dispersion plate, shower screen, portafilters, etc. As most of the internals are not in the coffee contact areas
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    Okay interesting. I guess I just figured that if I put in a liter of descaler, after flushing a couple of tanks through it would be gone, or at least not as much but it seems that it's not getting any better. I guess I'll just keep flushing the tank and hope for the best.

    In regards to the machine cleaner, I thought that was the case but the guide I followed specifically asked for citric acid or espresso machine cleaner, I thought it was weird but being a noob I followed it without question. Before tearing machine down I did soak dispersion plate, shower screen, baskets, portafilters when I back flushed the machine. I was finding froth/scale after backflushing multiple tanks before even tearing the machine down, so that's whats making me think it is not infact the espresso cleaner coming through but something else.

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    Senior Member trentski's Avatar
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    Dont worry about the clumps in the grind. The tamper takes care of them, or you can stir with a toothpick.

    Im a grind fine and tamp light kind of guy but as long as you stay consistent and change one variable at a time you'll work it out.
    Dose to 15 or 16grams tamp and then measure your pour over 30 seconds. Should be 50 to 60 mls, if less then coarser grind, if more then finer grind. Its that simple, don't stop when you get something you like the taste of, go a little further in case its better, if not go back a step and you're done.
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    Thanks mate, actually played around a bit before but I'm having a few issues with the stepped adjustment on the M2M it seems, It's certainly user error though. I ground on setting 4 and this was too fast, about 50ml in 15 seconds, so made an adjustment and went one increment finer but then this time it dripped out really really slow (almost as if channeling) but then loosened up and went for about 30 seconds, but did not taste bitter haha.
    '

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    Quote Originally Posted by Mrsr20 View Post
    I'm not following you completely in relation to flushing the pump. You say to flush with warm water in the tank, but isn't this what I have been doing? Since reassembling the machine, I have warmed the machine up and flushed approx three tanks worth of filtered water out of the machine.
    Sorry, what I mean is to put warm water into the water reservoir. I'm guessing you're just putting room temp or possibly cold water from the fridge in the water reservoir. Maybe try pulling the water reservoir out the front and empty right out then half fill it with the usual Brita jug water you use. Then slowly add recently boiled water a little at a time from your kettle, checking the water temp as you go (with a thermometer if you can, or a finger if that's all you've got). You don't want it to be too hot as the pump won't like it, and to be honest I'm not sure how much difference it'll make, but it could be worth a try. Flush a couple of tanks through like this and see how it goes.

  30. #30
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    Quote Originally Posted by Mrsr20 View Post
    Thanks mate, actually played around a bit before but I'm having a few issues with the stepped adjustment on the M2M it seems, It's certainly user error though. I ground on setting 4 and this was too fast, about 50ml in 15 seconds, so made an adjustment and went one increment finer but then this time it dripped out really really slow (almost as if channeling) but then loosened up and went for about 30 seconds, but did not taste bitter haha.
    '
    In that case take your setting 4 grind and updose to 16 grams or take the finer setting and dose 14 or 15 grams.

    Try and keep tamp pressure the same and grind the same so only the dose changes. If the dose starts to get ridiculous then change the grind and start again.

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    Quote Originally Posted by trentski View Post
    In that case take your setting 4 grind and updose to 16 grams or take the finer setting and dose 14 or 15 grams.

    Try and keep tamp pressure the same and grind the same so only the dose changes. If the dose starts to get ridiculous then change the grind and start again.
    Tried that and it helped a lot. Set dose to 16g and used same ramping and got approx 50ml in 23 seconds, shot tasted good but I definitely can dial it in more.

    Will now try to drop down one more increment to get 50ml in 25 seconds.
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    Quote Originally Posted by Mrsr20 View Post
    Tried that and it helped a lot. Set dose to 16g and used same ramping and got approx 50ml in 23 seconds, shot tasted good but I definitely can dial it in more.

    Will now try to drop down one more increment to get 50ml in 25 seconds.
    G'day Mrsr20

    Well done to get to where you are. A couple of minor points may be useful for you at this stage.

    Firstly, a lot of noobs (and even a few "not so noobs") do not realise that almost any grinder takes 14g+ for the new grind setting takes effect - it is even called grinder lag in the West Oz circles (probably universal - it is an exact description). To me if sounds like you need to run the grinder for a while at the point where you think it will settle in and then slowly fine tune from there. Chasing your tail is a really frustrating experience unless you are a puppy*...

    The scale - I also reckon it is just froth now. If the "prewarmed water" doesn't fix it, as Java said - flush again. I use vinegar on the rare occasions I have to deal with a friends machine. Even that takes over 6 litres before I can get a decent cuppa out of it. I gave up on the commercial "special coffee cleaners" years ago as they hung around too long afterwards. My own test - if I can detect a difference in the rainwater I use in the machine and the stuff directly out of my water tank then it needs cleaning / flushing or whatever until I cannot pick it.

    Congrats on getting from "absolutely nowhere" to "close to nailing it".


    TampIt

    *puppy: ... and no, I did not imply or infer any canine attributes on your good self. I do think some machines have the odd similarity...
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