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  • Channelling using Gaggia double baskets

    Hi Folks,

    Ive been experiencing 15-20 sec pours from my Gaggia Coffee Deluxe for quite some time. After this pour time, blonding sets in.

    I recently analysed my pucks (which were coming out dry and in one piece) and discovered a horizontal fracture in the puck. This horizontal fracture is at the spot where the basket tapers off towards the bottom of the basket. The basket shape is similar to the ones in this post from Greg Pullman (the double basket pic of the Rancilio Silvia basket):
    http://www.coffeesnobs.com.au/YaBB.pl?num=1169781510/

    When I split the puck, I noticed the color of the lower puck was much lighter than the color of the upper puck. So me thinks there is channeling happening as the grinds in the lower puck are more compressed than the grinds in the upper puck.

    I noticed there are other posts about channeling from Gaggia Classic owners using the Gaggia double basket. Maybe this is the problem.

    So, one could be of the opinion that a basket with less tapering (such as a La Marzocco double basket) would be a better shape basket. It might even "eliminate" that channeling Ive discovered.

    So what are other more experienced CSers thoughts on this?
    Have any other Gaggia owners using the Gaggia double basket examined their pucks and found this?

    Interested to hear others thoughts.

    Javabeen.

  • #2
    Re: Channelling using Gaggia double baskets

    Javabeen,

    Yep, horizontal channelling is cause for concern alright....

    I presume you are only doing only one "normal" tamp... in which case basket shape is quite possibly the reason.

    I can get a similar effect with normal (straight sided) baskets pretty much every time if I half fill, use a pretty heavy "settling" tamp, fill to normal level, and then tamp normally... there will be horizontal channelling at the level of the first tamp.... If I use just the weight of the tamper for the settling tamp this does not occur.

    Comment


    • #3
      Re: Channelling using Gaggia double baskets

      JB,

      I am doing the one normal tamp...however I grind to fill the basket, stop and tap the pf a few times to settle the grinds to make room for more grinds. Then I grind, fill then tamp. If I dont do this, then Im underdosing and get no screw imprint on the puck.

      The second fill is just a top up and does not put many more grinds into the basket - just enough to updose so I get the screw imprint. So I know this is not the point at which the horizontal chanelling is occuring.

      Javabeen.

      Comment


      • #4
        Re: Channelling using Gaggia double baskets

        Javabeen.

        In that case Id say basket shape is a significant contributor to the problem.

        Greg proved that there is not much sideways movement of grains during tamping and it is well known that the effect of tamping reduces the deeper you go in the basket.

        LM with their swift grinder tamps as they fill.... and only use 8Kg from the bottom to the top (for the same effect as a 15Kg tamp on the surface). Their single baskets also have straight sides - only half as deep.... The stepped sided single baskets cause all sorts of problems (and I believe that the shallow depth near the edges absorbs more of the tamp pressure - leaving the deeper centre portion less tamped - and a horizontal weakness at that level is produced).

        Id try a straight sided "normal" basket - and I reckon that will fix most - if not all - your problem.

        Comment


        • #5
          Re: Channelling using Gaggia double baskets

          JB the best way I found to solve this was to doub;e/split tamp. Fill the basket halfway and tamp lightly than finish filling the basket and tamp again more firmly. You may have to check your grind as well.

          Comment


          • #6
            Re: Channelling using Gaggia double baskets

            Lucinda, I dont know how it is that you dont get channeling doing this. Ive tried this in the past, and get channeling at the halfway tamp, even though Im only using the tamper weight to tamp. This is in line with what I thought i.e. tamping half way would create a line where later dosing would inevitably cause channeling at.

            I thought it might be my grind setting. So last night, I experimented.
            I managed to get an extraction of 21secs yielding about 48mls before blonding started.

            I tried grinding more course, and I got 60mls in 13 secs before blonding started. Taste was OK but way too watery and not very nice espresso.

            Checking the puck of all extractions, its the same thing. Channeling where the basket taper commences. I mean they knock out of the basket in one piece but when I analyse the puck, I can se a clear fracture line. I can then seperate the puck when I pull at it. Man, I must be obssessed to go to this level! No - I just want to get the best I can outta my equipment.

            Im realising 20 secs is the most Im going to get from these baskets...any other suggestions other than new baskets?

            Javabeen.

            Comment


            • #7
              Re: Channelling using Gaggia double baskets

              I do not get channeling and I do check my pucks. The times I do get early blonding is when I havent tamped correctly or when my grind needs adjusting.

              JB I have a heavyish tamper - though it will be interesting to see the difference once I have my very good Pullman Tamper next week.

              I think it is the nature of the Gaggia Classic to do 20 - 25 sec extractions. I think it is normal for this machine. I thought what we were looking for was a twenty secondish extraction and I have always had great coffee this way. It is almost always almost on the sweet side and very good.

              Comment


              • #8
                Re: Channelling using Gaggia double baskets

                Javabeen,

                Have you tried updosing? I find that I get early blonding if I dont updose on my Classic. Generally I aim to be able to feel the coffee hard against the shower screen after dosing, making sure its really locked in tight.

                I havnt actually weighed the dose, but its probably up around the 18 - 20g mark.

                Hope this helps?!

                Comment


                • #9
                  Re: Channelling using Gaggia double baskets

                  Like goose said - I use a 20g dose for my double basket too. I no longer use the single basket. Thought I may try it someday, when I can find it.

                  Comment


                  • #10
                    Re: Channelling using Gaggia double baskets

                    I will weigh my dose tonight as I dose by volume, not weight.

                    Lucinda and Goose, when you insert the pf with your 20g dose, is it tight to lock in right from the start when you put the pf into the group and try to turn it? Or is it just a little firm with the tightness increasing as you push the pf to the right? Mines the later.

                    Well, Im happy with the taste of my 20sec pours, like you said Lucinda, nice and sweet, it just that Im only getting 40-50 mls and I want more. I want to be getting in the range of 50-60mls. To get this, means I have to grind more course which means I end up with a faster pour and earlier blonding.

                    Maybe I should just be happy with the 40-50ml pour in the range of 15-20sec....

                    Javabeen.

                    Comment


                    • #11
                      Re: Channelling using Gaggia double baskets

                      Originally posted by javabeen link=1179883373/0#9 date=1179976743
                      Is it tight to lock in right from the start when you put the pf into the group and try to turn it? Or is it just a little firm with the tightness increasing as you push the pf to the right?
                      Not tight, but pretty firm just after I start locking in.

                      Perhaps try grinding just a little finer? You said your getting 48mls in 21 sec before blonding, if the grind was a little bit finer you should be able to stretch out the time before blonding. Not so much to slow the pour dramatically, just so that your getting a better extraction of the coffee in the pf.

                      Comment


                      • #12
                        Re: Channelling using Gaggia double baskets

                        Mine is a little tighter so that is normal. If it is not tight the shot just goes awful.

                        I usually get a 50 - 55ml pour of the shot too but I have found that it hasnt affected the taste etc.

                        I think that 60 ml is basically the average. If some machines produce a 50ml shot and it tastes okay, I wouldnt really worry about it.

                        Comment


                        • #13
                          Re: Channelling using Gaggia double baskets

                          Originally posted by javabeen link=1179883373/0#9 date=1179976743
                          I will weigh my dose tonight as I dose by volume, not weight.
                          Dosing by volume is by far the most used and preferred method jb, so I wouldnt get too hung up on the actual weight of coffee in the basket. Its much more important that the dose is distributed evenly, kisses the shower-screen/nut after tamping properly and that the PF can be locked into place correctly.

                          Originally posted by javabeen link=1179883373/0#9 date=1179976743
                          Well, Im happy with the taste of my 20sec pours, like you said Lucinda, nice and sweet, it just that Im only getting 40-50 mls and I want more. I want to be getting in the range of 50-60mls. To get this, means I have to grind more course which means I end up with a faster pour and earlier blonding.
                          Personally, I quite often grind so that my pours finish a little early as the brews do turn out a lot sweeter and sometimes thats just what Im looking for with some coffee varieties/blends/roast levels. If you are confident that your dosing, distribution and tamping is consistently where it should be then the only things that remain, as has been said already, is the coffee itself and the PF Basket. Just changing one of these things at a time is the only way you are going to arrive at the reason for your early-blonding shots.

                          One of our other members dsc is experiencing a similar kind of thing with his Gaggia and in his case it looks like it could be more to do with his grinder than other factors, as his grinders burr-plates are not parallel resulting in all sorts of grind sizing problems. Is there any chance that you can borrow or gain access to another good quality grinder in an effort to remove this as a possible cause? Would definitely narrow the potential problem(s) down pretty quickly and is easy to do.

                          Originally posted by javabeen link=1179883373/0#9 date=1179976743
                          Maybe I should just be happy with the 40-50ml pour in the range of 15-20sec....
                          Never be happy with less than the best that is possible jb.... Gaggias have an excellent name for producing high quality espresso on a continuing basis so I personally wouldnt be happy until you are getting what will make you happy, without qualifications....

                          Mal.

                          Comment


                          • #14
                            Re: Channelling using Gaggia double baskets

                            Thanks for all the feedback guys.

                            Mal,
                            I always dose by volume so agree with you there. I did weigh my dose out of curiosity and its 21 grams. I weighed the dose in the pf basket as opposed to the beans I put in the hopper.

                            AS for the grinder, Ive had the Iberital Challenge for just over a month now as an upgrade from the Sunbeam EM 0480. I didnt get channeling with the Sunbeam however the shots are better from the Iberital. I could not dial in the Sunbeam on some days and it was a real nuisance.
                            I checked the burrs on the grinder. The centre one is fixed well and there was now paly when I moved it. The outer burr was also fixed rock solid. There was no visible "play" in the burrs when I switched it on.

                            Good news to report this morning. Im thinking the channeling problem is a combination of the basket and the beans.
                            I made 2 shots this morning from some 2 day old India Harar Id roasted. First shot took 27 secs and 2nd 29 secs before blonding started. I let the 2nd run a little longer to see the taste difference. For both shots you could say the shots were sweet as the sweetness was more noticeable than the bitterness - as I had less blonding this time round. 2nd shot was a little more bitter as expected.
                            I analysed the pucks. The fracture line was still there. Bizzare thing is the color when I split the pucks was even throughtout, even where the fracture line seperated the two pucks.

                            Ill report on my next few shots and see how I go.

                            Javabeen.

                            Comment


                            • #15
                              Re: Channelling using Gaggia double baskets

                              Great news jb,

                              Progress at last ;D

                              Mal.

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