CoyoteOldMan have fun in France!

This sounds probably the cause. I recently home made a WDT tool with wine cork and sewing needles. I stir in small circular motions from bottom (really touching and scratching the bottom of the PF) to top because I learnt the importance of even distribution.

Re the clumps, I kept thinking why I had quite a bit of clumps maybe because I tap the sides of the grinder and also tap the bottoms and the bottom corners of the collecting cup attaching to the grinder to the table pretty strongly to try to get the last big out from the burrs. Because I saw some particles between the burrs. I did it for 15-20 times depending on mood. I developed this habit gradually and maybe this slowly impact my puck condition.

    Knluk I would stick with the bottomless basket as the spouted PF will reduce the temperature of your shots unless you preheat it. You can also get a better idea of what’s happening with a bottomless, especially with preinfusion (as the basket slowly starts dripping), even though you shouldn’t let some channeling make you think that the grind is incorrect!

    I also think your shots seem messier because it’s a lighter roasted coffee and so is harder to extract as easily. With a very dark roast this may look nicer to the eye and extract easier because its more soluble, but a lighter coffee can cause more issues to fully extract. I don’t think your preparation will necessarily be getting worse. It takes time and patience so just try to stay consistent with everything you do and change one setting (grind) for the time being.

    With the shot you grinded finest but there were channels, did you taste bitterness like with the last coffee beans?

        FadedFrontiers thanks. Good point on the temp.

        Yes. It is mainly the striking bitterness we cannot get rid of. And yes- from the colour, it is a pretty lighter roast compared to the oily bean I had before

        I think one of the tricky part confused me before was the relationship between grind size/ pressure/ time. Eg when I could get close to acceptable pressure (day 5-6 bar) and time (eg 30s), but the taste is bitter, should I use to coarser grind. But when i continued to move to the grinder size, either or both of the pressure and time will change to a funny level. But I got it now that I should ignore the pressure and time first. Still not sure what will happen next but the beautify of this forum is I can restart and report back the progress step by step for advice. I will restart from 1.7.0 grind today.

          Continue working on the Brazil beans today. I kind of doing some unlearn and relearn here and try to do simpler puck prep for better extraction. However, I still find quite significant clumps most of the time even after tapping the grind collector lightly and tapping the sides of the PF 3-4 times. And up and down tapping the bottom of the bottom of the PF to the table mat. So I lightly use WDT to break down the whole surface section to get rid of the clumps.

          I tried to give it a bit more patience this time and changed grind size really marginally. So not much more observable indication can be drawn. But at least I improved my reporting skills :)))

          (Texture: 10 is thickness, 5 is medium, and I prefer 6-7)

          During the pull, I did not pay any attention on channelling , brew time and pressure. But I watched the filter bottom video afterwards and report anyway (10/10 means channeling free)

          Any comments will be highly appreciated

          • MWJB replied to this.

            Knluk How do you propose to influence the “thickness”? This would normally be achieved by grinding finer (which increases bitterness) and/or pulling shorter. (It’s not something I would personally aim for as short, thick shots can get in the way of the flavour, but everyone has different preferences).

            The shot that channelled more tasted better (or at least no worse), so ignore what you think is channeling (it probably isn’t).

            Isn’t your pressure in pounds, not bar?

                MWJB Thanks! Make a lot of sense regarding thickness.

                I re-examine the video of the last shot today. I think the flow is not as full compared to the dark roast. And weaker in some of the hole but you are right that there is no channeling. Not sure how I made that remark :) . I probably just prefer the beauty of the full of crema flow. But that’s not as key as the taste.

                Yes. Should be in pound. But I just take it by feel. Don’t want to overcomplicate it as advised by you before.

                Does it make sense to go coarse? Appreciate that.

                • LMSC replied to this.

                    Knluk It’s a good shot, although the beading starts on the top and left to right on the video. This suggests a potential weaker spot on the top and left as per the video. But, I will be happy with that and won’t worry about your WDT. This just leaves one doubt if you are actually confusing the natural bitterness in the espresso with medicinal bitterness. Is it medicine or a paracetamol bitter?

                        LMSC cool. That means I just not familiar with the relatively light roast beading only.

                        Hm… honestly I am not good at describing taste. But I think it lean more toward to the medicine like bitterness and the after taste bitterness leaves there long. Compared to the expresso I had in cafe (where I prefer slightly more bitterness than sourness), it is different but not hugely different by nature. But the bitterness in my shot Is definitively striking and not pleasant. Sorry I cannot describe it better. But I appreciate your help.

                        If my beading is okay, I will then move to coarser to try until the shot got problem such as very watery and extremely short brew time. And at that time if I still have this Brazil beans left, I will go another direction to try something coarser than the start point, ie 1.7.0. Make sense?

                            Knluk I would try pulling this grind setting again but with less preinfusion time, see how that tastes. If it’s still bitter try lowering temp by a degree or two (temp may also be worth adding to your chart too to keep track of).

                            I also recommend you up the dose from 15g to 16 or 17g of coffee. The Robot is capable of doing doses as small as 12-14g but I’ve always found those harder to get the most out of. It’s far more forgiving with larger doses which I imagine is down to the depth of the basket.

                                FadedFrontiers sure thing. Do as instructed :)

                                1. The first shot was similar to yesterday’s. Temp was reduced from 95c to 93c and increase dosage from 15g to 16g. Also, preinfusion was shortened to 5s.
                                2. The second shot - I further increase dosage to 18g. This showed observable improvement. Still bitter but less striking and less long lasting. But LMSC i paid attention to it. Yes- I am pretty sure that it is me medicine like bitterness. But this shot is marginally drinkable. I don’t enjoy it much. But I will drink it when I crave for coffee. Also, notice some floral smell and after taste. But lack of sweetness.
                                3. Third shot - I kept everything the same but with some confidence built up(?) I decided to coarse up the grinder by one click and pretty confident that it will show slightly improvement. But it returned to the level of yesterdays. Pretty frustrating for this :( Below is the video of the last shot.

                                With my fast speed wasting bean (but I appreciate all the learning), I will use up my Brazil bean in a day or two. Plan to stick to the best shot today and try to pull a shorter shot. My thinking is to get rid of the last part of the shot which is bitter. Does it make sense to all fellow members here?

                                      Knluk My thinking is to get rid of the last part of the shot which is bitter. Does it make sense to all fellow members here?

                                      You are free to do whatever works for you, but no, discarding the last part of the shot makes no sense. Just pull a shorter shot if that is what want.

                                      In a balanced shot, even if the last part of the output is weaker & bitter, the shot will still be good, because the early part will be under-extracted & sour, even if you kill the shot when the last drops taste good on their own (this is something I have explored in the past - discarding 1st drips, discarding last part).

                                      Why not just make 3 more shots at 1.7.3, 18.2gin, 37.1g out and ensure that they are consistent?

                                      I’m a bit confused by your scoring and analysis, you are scoring out of 10, so 5.5 would be neutral, neither like nor dislike, 6.5 would then be a positive score in that it was likeable, but you have had better & know there is room for improvement, yet you say, “But this shot is marginally drinkable. I don’t enjoy it much”? 6.5 might be a score I’d give to representative shot of mass market espresso blend, where I’d be perfectly happy with it in context and I wouldn’t ever expect a 9 from it.

                                      The scores of 5.4 to 5.6 are all essentially the same thing, differences of +/-2%, which are inseparable from noise. Try and simplify the scoring & make a call to keep to whole digits, or 0.5 intervals.

                                          MWJB yeah see how consistent the shots are at the same setting for the next few attempts. Different tamping pressures could cause different results for example, you could always try to record the pressure you tamp with.

                                          My next step is a counterintuitive based on the bitterness but I’d actually grind a little finer and see how that affects the taste (try one click at a time). I say that because the higher dose at the same grind (which resulted in higher pressure) was the best shot so far.

                                              Knluk your beans are super dark roasted judging by the pic - they look almost black and oily, I think the bitterness you describe is not fixable for these beans. I suggest getting a medium roast - these in my experience respond better and more predictible at changes in recipe.

                                                  MWJB thank you! Always appreciate all the useful suggestions. And I shall try three more shots for the best shots.

                                                  Re the scoring, i was using a school examination, 60% pass score, and maybe 80% very good and 90%+ excellent. I have to admit that I think about it systematically in the first place 😂

                                                    90% coffees (in terms of cupping potential) are extremely rare.

                                                    My brews average about 84% a mix mostly of 7 & 8’s (out of nine).

                                                      Petre the thread May be confusing.

                                                      I am now using this beans which I think is medium dark roasted. see pic below.

                                                      Below is the last bag of beans I used:

                                                          MWJB what is your score for drinkable?

                                                          I may have a different scale. If I drink a nice coffee from a random speciality cafe, I give it a 8.5 or 9.0.

                                                          • MWJB replied to this.

                                                              Knluk oh alright then, the first ones look more like medium indeed.

                                                                Knluk when you’re ready to tamp, just put the filled basket on top of a bathroom scale and see what sort of pressure you register as you push down normally with the tamper. 20-30lb of pressure is always mentioned for standard espresso machines but it shouldn’t matter too much provided you’re consistent (I’ve found a light fingertip tamp to be fine for the robot, just try to keep it the same each time and most importantly keep the level with the tamper handle in the middle as much as possible).

                                                                I only suggested it because I imagined you’d been using a bathroom scale for measuring the pressure with the robot arms, it shouldn’t be a huge factor but just something to keep in mind.