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  • overdose/underdose and how it affects taste

    Hello everyone,

    Yesterday I got some fresh coffee and decided to try out weighing the coffee before dosing. I grind into an espresso cup and after measuring 18g I put it into the basket. The problem is that 18g is a lot more than the basket can take in one take, so I have to dose some, tap on the counter and add the rest. After tamping it leaves me with about 1cm of space above the coffee puck and it almost touches the shower screen. While brewing the coffee expands and theres a nice shower screen impression on top of the puck. Heres how the puck looks like when dosing 18g:



    dont know if you can tell anything from the colors of the puck, but you can see its darker in some places. The other side looks even, with no holes or anything, just the shower impression I was talking about.

    I also made a try with 14-15g dose and heres how the puck looks like:

    bottom:



    the other side:



    It had a lot of holes, but the whole thing broke while I tried to remove it from the basket. Still one hole is visible, its highlighted with a red circle.

    The 14g shot had some spiting and dead spots (places where theres almost no flow, which creates a depression in the cone and you can almost see the bare basket).

    Now my question is: what should I do? it looks like overdosing is good for chanelling problems, although Ive read in many places that it can have a negative effect on the taste. On the other hand 14g doses keep giving me uneven extractions. Could it be that the Classic needs to have more coffee to give a good even shot?

    I also noticed that my crema is really, really dark, almost black and its really bitter in taste. Maybe my grind is too fine? Oh and I get bubbles on top of it, small 1-2mm bubbles. Temperature problems? I would give a lot to have a PID...

    Cheers,
    dsc.

  • #2
    Re: overdose/underdose and how it affects taste

    Originally posted by dsc link=1174665207/0#0 date=1174665207
    Hello everyone,

    Yesterday I got some fresh coffee and decided to try out weighing the coffee before dosing. I grind into an espresso cup and after measuring 18g I put it into the basket. The problem is that 18g is a lot more than the basket can take in one take, so I have to dose some, tap on the counter and add the rest. After tamping it leaves me with about 1cm of space above the coffee puck and it almost touches the shower screen. While brewing the coffee expands and theres a nice shower screen impression on top of the puck. Heres how the puck looks like when dosing 18g:



    dont know if you can tell anything from the colors of the puck, but you can see its darker in some places. The other side looks even, with no holes or anything, just the shower impression I was talking about.

    I also made a try with 14-15g dose and heres how the puck looks like:

    bottom:



    the other side:



    It had a lot of holes, but the whole thing broke while I tried to remove it from the basket. Still one hole is visible, its highlighted with a red circle.

    The 14g shot had some spiting and dead spots (places where theres almost no flow, which creates a depression in the cone and you can almost see the bare basket).

    Now my question is: what should I do? it looks like overdosing is good for chanelling problems, although Ive read in many places that it can have a negative effect on the taste. On the other hand 14g doses keep giving me uneven extractions. Could it be that the Classic needs to have more coffee to give a good even shot?

    I also noticed that my crema is really, really dark, almost black and its really bitter in taste. Maybe my grind is too fine? Oh and I get bubbles on top of it, small 1-2mm bubbles. Temperature problems? I would give a lot to have a PID...

    Cheers,
    dsc.
    Just a thought re the darkness, almost black crema and bitterness. These are signs to me of over temperature and/or very slow extraction. You could consider brewing at a different time in the gaggias heating cycle- you could wait longer after the heating element turns off, or you could flush out any boiling water after the element goes off. You could also try dosing just a little less, because if the coffee is in contact with the showerscreen too long, or the brew time is too long...
    A PID is brilliant but you can also play around with temp surfing. Try 2mcms tamping method, works for me- fill , tap on bench, level off, sit tamper in to compress a little, refill, level off then tamp.
    Brett

    Comment


    • #3
      Re: overdose/underdose and how it affects taste

      Hello Brett,

      Funny thing I noticed today, I used a coarser grind and 18g of coffee. The result was a pretty fast pour, started flowing after only 5s and formed a huge cone, which was really bright. Stoped it after 27s when blonding appeared and had a cup almost full of coffee, so I thought:

      "hmm 60ml, for a double, the time is quite ok, but the cone was really bright, hmmm what the hell"

      Waited 1min and it turned out I only have around 35ml in the cup, the rest was only crema.

      So Im not sure what to do now, because:

      - when I use a fine grind and 18g I get a really slow pour, not more than 40ml in 27s, dark crema, with bubbles and some coffee gets through the basket, which means the grind is too fine

      - when I use a coarser grind and 18g I get a really fast pour, a giant cone which is really blond and also no more than 40ml, cause the rest is crema

      so what the hell is wrong? This is really starting to iritate me...

      Cheers,
      dsc.

      Comment


      • #4
        Re: overdose/underdose and how it affects taste

        I did a bit of experimenting with downdosing. I have found that a finer grind combined with a firmer tamp firms up the puck in a downdosed PF. This was with 13g. Compared to the normally dosed PF, the grind size on my mini was 2 1/2 ridges finer on the collar.

        Flavour was much different than the normally dosed shot. With the normally dosed shot, there was a lot more brightness in the cup. With the downdosed shot, the brightness was subdued.

        I believe there are merits in downdosing, especially when coupled with Gregs findings with tamp force/puck compression. In the case of downdosing, 3kg extra of tamp force turns a soggy puck into a firm one.


        dsc: Is the difference in grind only one step on the grinder? If so, you may have to adjust your tamp slightly firmer. Theres nothing wrong with the restricted second shot. Probably a bit more intense flavour.

        Comment


        • #5
          Re: overdose/underdose and how it affects taste

          Ola nunu!

          The thing is that the Classic likes to get more coffee in the basket. If I dose less I always get channeling, spiting and other wierd things happening. I guess more coffee makes the puck lock between the shower screen and the basket, so water cant do much damage to it.

          I did some experiments and found out that 18g and a pretty fine grind makes things good. Altough I still get twisted cones and swirls on my NPF.

          One question: should the puck have the same color everywhere? I mean for example dark brown all around or can it have darker places? I ask because Ive read a new topic on channeling somewhere in these forums and the person (Kiwi_Jonno) said that:

          "I carefully knocked the pluck out and noticed it was a lot darker (wetter) around the edges. Although it was clearly wet in the middle, and all the way thru the pluck, the edges were a lot darker as if channelling down the side had occured. "

          So dark edges are a sign of channeling?

          Cheers,
          dsc.

          Comment


          • #6
            Re: overdose/underdose and how it affects taste

            Hi dsc

            I guess your problems with downdosing could be related to the rather high factory setting of the OPV (approx. 11bar). At least with my classic it helped me a lot. at first i wanted to post it in here but then it seemed like hijacking the thread; so I made a new topic on pressure modifications for a gaggia classic here.

            What conderns the adjustment of the grind for downdosing: for my current beans and my MDF I had to adjust the grind 0.4 steps per gram.


            This video is from a 13.8g shot (weighed post distribution with the basket out of the pf method). Altough there are signs of channeling (the bubbles which appear on the cone between 12 and 22 sec into the pour) the shot tasted good.


            saluti

            marco

            Comment


            • #7
              Re: overdose/underdose and how it affects taste

              dsc, I always use 19-20g of coffee in the basket on my classic. I also have found that tamping twice, as you do also gives great results.

              Make sure that before you put the filled pf back on the machine that you give a quick flush of hot water - this stops overheating and burning. I also have found that I have may grinder on 4 for all coffee, I know that individual grinders are different but I think Hazbean has his set on the same setting too. I actually have never had to adjust my grinder up or down from this, thoough it may depend obn the beans you are sourcing and how fresh they are.

              Comment


              • #8
                Re: overdose/underdose and how it affects taste

                Hello,

                Marco: I already reduced the OPV setting, so the problem probably lies some place else. Will do a double check in the following days and report back.

                Lucy: today I tried splitting my 18g dose in half. Used the first 9 grams, tamped only with the weigh of the tamper, poured the rest and tamped again but this time more seriously. Works pretty well, but I often get a canted tamp and the cone is not centered. Because of that one half of the coffee cake gets extracted faster and after around 15s the cone moves to the other side. This causes channeling and swirling of the strips. Will try to catch it on video and show it to you

                Cheers,
                dsc.

                Comment


                • #9
                  Re: overdose/underdose and how it affects taste

                  Okay - try upping again to 20g. I am not sure of your tamping method, though if your tamper is a bit too small for your basket you may have to use the N S E W method and when you do tamp make sure your arm is pushing straight down onto the coffee/tamper, this should keep the coffee even across the top.

                  The gaggia does not like underdosing I have found, so overdosing is the best way.

                  Have a try of these and see what you come up with.

                  Comment


                  • #10
                    Re: overdose/underdose and how it affects taste

                    So many pros and cons on this issue.
                    Equipment
                    Blends
                    Roast
                    weather
                    Underdosing will not work as well under hot weather and really fresh coffee. Also with milk drinks how how much milk is there? Commercial use in the Australian market 18grams is going to taste better with milk than 14grams. I think its a matter of what you like.

                    I currently mix the 2 theories together. We use 24 gram baskets and dose it at 18-19 grams. We get expansion of the puck which doesnt smash onto the shower screen. Shots are cleaner and its so much faster to make coffee. Pre infusion is a second or so longer and coffee is so sweet. Pucks are great, and with these triple baskets they have an even extraction under the naked portafilter. Even drop nearly every time.

                    Andrew

                    Comment


                    • #11
                      Re: overdose/underdose and how it affects taste

                      Overdose, underdose, Wombling free,
                      too much of the coffee is not good for me,
                      But upping the dose gives the shot that is right,
                      How do I choose between healthy and like. . .

                      Comment


                      • #12
                        Re: overdose/underdose and how it affects taste

                        Originally posted by grendel link=1174665207/0#10 date=1175491489
                        Overdose, underdose, Wombling free,
                        too much of the coffee is not good for me,
                        But upping the dose gives the shot that is right,
                        How do I choose between healthy and like. . .

                        [smiley=grin.gif] [smiley=grin.gif] [smiley=grin.gif] [smiley=grin.gif] [smiley=grin.gif]

                        Comment


                        • #13
                          Re: overdose/underdose and how it affects taste

                          Originally posted by grendel link=1174665207/0#10 date=1175491489
                          Overdose, underdose, Wombling free,
                          too much of the coffee is not good for me,
                          But upping the dose gives the shot that is right,
                          How do I choose between healthy and like. . .


                          I dont like to say this...but grendel you may have had too much coffee.

                          Comment


                          • #14
                            Re: overdose/underdose and how it affects taste

                            Hello,

                            Overdose, underdose, Wombling free,
                            too much of the coffee is not good for me,
                            But upping the dose gives the shot that is right,
                            How do I choose between healthy and like. . .
                            Thats a good one mate!!

                            As for the dose Im currently working with 18grams and it works pretty well. My tamper is 57,9mm and the basket is said to be 58mm, but its in fact a lot wider on top and measures 58,8mm. Im using the NSWE method, because without it I get side channeling.

                            Im currently waiting for a new batch of fresh coffee. Will post some results at the end of the week.

                            Cheers,
                            dsc.

                            Comment

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