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  • Advice on change in coffee flavour

    I am after some advice. I have a rancilio Silvia, about 4 years old, and a sunbeam burr grinder. Have been making excellent coffee for four years and suddenly it seems bitter. Still a great crema, but slight acrid aftertaste. I have cleaned the group head, de scaled, bought new beans, cleaned the grinder, can't work it out. The changes I have noticed: scent of the poured coffee is not great, grounds seem to have flecks (might not be new).

  • #2
    Do the grinder burrs need replacing, or re-alignment? Alternatively maybe the boiler temp may need re-adjusting if it hasn't been touched in the 4 years you have owned it.

    I noticed that my Sunbeam EM0480 was changing sounds mid-grind and it appeared the burr was a little loose, wobbling ever so slightly on its axis. This was causing a wide range of particle sizes on finer grind settings and a noticeable amount of the light coloured fibrous material (I'm told that this is caused by beans being torn apart rather than ground). I haven't fixed my Sunbeam yet as I upgraded it recently so I don't know if would be the cause / solution to your issue.

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    • #3
      Hi Tizzy,

      Have you taken the shower screen off and cleaned it thoroughly? Also the beans you buy do you prepare them any other way such as plunger or stove top? I ask this as if you do and that has changed in taste also you can then eliminate the machine. However from the info you have told me i'm thinking the machine.

      Regards,

      Chris

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      • #4
        The increase in fibrous material meaning the beans are being ripped up rather than ground rings true - I have been noticing that, but wasn't sure if it had been happening before.
        I might do a few net searches on fixing the grinder and see if I can find something to fix there.
        I don't know about the temperature of the boiler and haven't gone to the extent of adding a PID because I was getting great coffee with gorgeous crema and lovely taste up until a month ago. I was hoping that I could fix it myself.

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        • #5
          Hi Coffeechris, yes I have cleaned the screen. I don't grind for any other grind than espresso, But I was given a batch of badly ground coffee that I tried to regrind (a tablespoon) before rethinking the plan. But I also put that through the Silvia.
          too many variables for me!

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          • #6
            So I bought some freshly ground coffee and pulled a couple of shots - I am still getting a slightly bitter aftertaste and the shots don't smell full and sweet. Is there any way that I can confirm if it is the boiler temperature, and direct me to,where I can findfind out more about that?

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            • #7
              Yep, bitterness could be caused by temperature being to high. You can try some temperature surfing..
              1. Turn machine on and wait for 30-60 min.
              2. Then press brewing button and wait till light goes on (at this moment temp is too low and heating starts).
              3. Wait till light goes off. At this stage temperature close to the max. This temperature supposed to be always the same on your machine.
              4. Wait for X minutes (longer you wait, lower the temperature) , make coffee. If by waiting long enough before making your coffee you improve the taste - then the problem is due to the temperature.
              5 can vary X and make your judgement. If you can get the good taste by temp surfing - consider fitting PID.

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              • #8
                You mention that you have descaled, have you ever back flushed the machine?
                Backflushing... please explain what it is - Tips and Techniques • Home-Barista.com

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                • #9
                  Hi, thanks Yelta and Viktor,
                  i have been temperature surfing the Silvia to get a shot, and I have been descaling every three or four months and back flushing regularly.
                  and when this flavour change happened I descaled, back flushed, changed the beans, cleaned the group head. Today I reset the thermostat, in case that worked.
                  but no, the shots still look gorgeous but don't smell right and have a bitterness.
                  Perhaps I have stuffed the thermostat somehow?

                  Comment


                  • #10
                    Originally posted by Tizzy View Post
                    suddenly it seems bitter. Still a great crema, but slight acrid aftertaste, bought new be,ans grounds seem to have flecks (might not be new).
                    [QUOTE=Tizzy;514662] But I was given a batch of badly ground coffee that I tried to regrind (a tablespoon) before rethinking the plan.

                    Originally posted by Tizzy View Post
                    So I bought some freshly ground coffee and pulled a couple of shots - I am still getting a slightly bitter aftertaste Is there any way that I can confirm if it is the boiler temperature, and direct me to,where I can findfind out more about that?
                    Hi Tizzy,

                    Welcome to CS!

                    Online diagnosis is notoriously difficult and the information you have provided doesn't paint a clear picture.

                    It would help if you make it to 5 posts and then use the ability to post some pics.

                    *pics of the 'flecks' in the grounds. Are they evident in the grinds as well? (grinds.....pre extraction; grounds....post extraction)
                    Does the centreline of the beans you are using have remnant chaff?

                    *pics of a shot, freshly poured, with crema intact, before it dissipates.

                    *Using pre ground coffee to diagnose the issues is problematic.

                    *water that is too hot is normally easy to pick if you drink it.

                    *Where on your palate are you discerning the 'bitter taste'..... the very front or very back of your mouth?

                    *Has the shot time remained constant, has it slowed down or sped up, relative to the previous 4 years?

                    *The comments above re backflushing and cleaning are very pertinent. What has your regime been? Has it been regular and frequent?
                    You mentioned de-scaling..... did you do this yourself? Is there chemical residue in your machine?

                    *Even if you have used the same brand of coffee for 4 years there is no way that the beans are the same. What have you been using? Are they dark or medium roast?
                    Are they from a reputable roaster or from the supermarket?

                    There are a lot of skilled and very helpful people on the site, I'm sure you will get some help.

                    Comment


                    • #11
                      Have you noticed a change in temp of your shots?

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                      • #12
                        Thanks for your help.
                        i have been doing a pseudo scientific study of the problem and think that it has something to do with chemical residue rather than grind or temp.
                        The water that comes through tastes tainted - back of mouth, acrid taste.
                        So I am thinking that we are descaling badly and suffering from chemical residue?
                        i have been using 'clean machine' descaler. I ran 10 litres of water through it last weekend and it is still tasting tainted.
                        I am going to keep running water through, but any other suggestions would be greatly appreciated.

                        Comment


                        • #13
                          Originally posted by Tizzy View Post
                          Thanks for your help.
                          i have been doing a pseudo scientific study of the problem and think that it has something to do with chemical residue rather than grind or temp.
                          The water that comes through tastes tainted - back of mouth, acrid taste.
                          So I am thinking that we are descaling badly and suffering from chemical residue?
                          i have been using 'clean machine' descaler. I ran 10 litres of water through it last weekend and it is still tasting tainted.
                          I am going to keep running water through, but any other suggestions would be greatly appreciated.
                          Hi Tizzy

                          Please check the Silvia manual before doing this, however it should be OK (haven't owned a Silvia for years, and I cannot recall ever needing to do this to the lady...).

                          How I used to get rid of the dreaded "fish oil taint" in a lot of commercial machines when all else failed. Add about two tablespoons of white vinegar per litre of "clean" water. Do the normal backflush thing. Then run at least half a tank of it through as a normal "coffeeless shot". FWIW, I used to run one shot first with rubbish coffee, however I do not think it made any difference.

                          You will need to rinse it all out thoroughly afterwards, however I found it not only killed the taint, it was less persistent than most "specialised cleaners".

                          Also, I had two 480's until recently. If yours needs shimming, there is no way to escape the bitterness. You may have two problems: water & grinder. Didn't you RTFM page 7 "Note: This coffee grinder is intended to grind whole coffee beans only."? Putting previously ground coffee into the hopper can kill most grinders as they overheat the burrs and destroy the tempering (i.e. need to replace the burrs, but try shimming it first anyway). The good old "white paper test" or the "finger test" (Page 12) can let you know if this is needed. Hopefully not!

                          Enjoy your cuppa (soon we hope)

                          TampIt
                          Last edited by TampIt; 10 January 2014, 10:35 PM.

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                          • #14
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                            Ok, so we have flushed, over 5 tank loads, and the coffee is still bitter, back of mouth acrid taste (sorry, my descriptions aren't too accurate)
                            I am wondering whether there are two issues 1. The initial problem with bad taste; 2. Chemical residues from too much descaler.
                            I was descaling once every three to four months, with a descaler bought from the company I bought the machine from. It may be too strong, and we may have added chemical reside to our problem. But I think we have rinsed the machine enough!
                            The water tastes fine so I made a shot hoping to have a gorgeous coffee.
                            but no, bad pour, smells thin, looks too dark and the crema too blonde.
                            the shots pour ok, in a thin stream over 20 secs, the biscuit is a bit too damp, tastes terrible.
                            the shots are around 78degrees, don't seem to have got hotter or colder.
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ID:	736933I did test the grinds and they seem consistent, feel like salt grounds. a month ago I did buy preground coffee to check, but it didn't seem to make any difference to the flavour.
                            any way I can check whether it is a thermostat or pressure issue?

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                            • #15
                              Originally posted by Tizzy View Post
                              The water tastes fine so I made a shot hoping to have a gorgeous coffee.
                              but no, bad pour, smells thin, looks too dark and the crema too blonde.
                              the shots pour ok, in a thin stream over 20 secs, the biscuit is a bit too damp, tastes terrible.
                              the shots are around 78degrees, don't seem to have got hotter or colder.
                              [ATTACH=CONFIG]5335[/ATTACH]I did test the grinds and they seem consistent, feel like salt grounds. a month ago I did buy preground coffee to check, but it didn't seem to make any difference to the flavour.
                              any way I can check whether it is a thermostat or pressure issue?

                              Hi Tizzy

                              78 is far too low to pour a decent shot. 92 is usually regarded as a minimum. My first priority would be to check that in a hurry! From your comments plus the photo, the pour is way off. The grind looks OK (bit of minor clumping), and with that dosing it should pour a little long if anything. Clear evidence of a machine problem somewhere. The pump is actually overdelivering if anything so the control system must be skewed. Sensor failure? Did you do the white vinegar thing? If so, read on...

                              If you are not into tinkering, the Silvia is probably at the "take it to experts" stage.

                              Also, I would regard the above photo as a clear fail at the grinder end. Too many fines: it would certainly tend to go bitter early in a (correct) shot. Check http://coffeesnobs.com.au/brewing-eq...w-machine.html for shimming info and further links. I confess to a little puzzle here: usually when a 480 needs shimming it would have a lot more coarse particles as well. This photo doesn't show that. Your "fibre" comments earlier did. Scratching head...

                              I hope you can nail it (I hate it when good gear plays up).

                              TampIt

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