Announcement

Collapse
No announcement yet.

Large extraction variances day to day

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Large extraction variances day to day

    Hi guys,

    I'm really scratching (banging more like it) my head on this one, and am hoping someone can help.

    I had a Sunbeam em7000 for around 8 years, it was matched with a Compak K3 grinder.

    A few months ago I started noticing some large variances in extraction times from day to day and sometimes even shot to shot.
    I'm talking about single shot extraction times varying as much as 10s or more. And I also found small changes to grind pushing extraction times in the other extreme.

    Figuring it was probably my technique I started weighing my dose, using a distribution tool, paying particular attention to how I tamp... This did not seem to help.

    I then bought a new machine (ECM Technika V) and changed the burrs in my grinder. While I seemed to get some consistency for a week, inconsistencies have since returned.
    I then bought a naked filter... Extractions are not perfect (with a couple of dead spots) but they are by no means bad; there is also no spraying from the extraction.

    I have no idea what could be causing the large variances in extraction since the only thing I haven't changed is me (but I'm confident it's not my technique anymore).
    The only other thing I can think of is that I moved house about 5 months ago and this house can get quite hot (and I assume humidity varies a lot too)..

    I'll start monitoring humidity, but are there any other suggestions from you guys?

    Thanks for your help!

  • #2
    Just a bit more info.
    I'm using a VST 18gm basket and a 58.3mm tamper. When I'm tamping I'm very careful to not create a vacuum and suck the puck out.

    I'm also finding generally (not always) the puck will knock out cleanly.

    I generally only make 2 drinks a day: morning and afternoon.
    If I have friends over I might make 5 drinks a day. I've found at times I can pull 3 back to back shots and they can be wildly different, or they could be really consistent.

    I purge the grinder on the first shot of the day.
    And while I do change beans every so often, I don't chop and change on a daily basis, generally I use the same batch of beans 500gms at a time .

    Essentially I've done everything I can think of to ensure consistency, and even if there were variances in extraction (which is to be expected as coffee is a natural product) I don't think there should be variances of this magnitude.

    Or do I have unrealistic expectations? How much do your extractions vary from day to day or intra day?

    Comment


    • #3
      Just a few thoughts, however I'm sure some more storied colleagues will have better advice than me.

      Firstly, do you notice a difference in taste? That should be the most important factor. However consistency is always a good thing so I can understand your frustration.

      Otherwise, can you factor in other potential sources of variation? For example group head and/or portafilter temperature - e.g. these could possibly be a bit warmer after the first shot when going back-to-back. Are you warming up the handle to the same temp as the group for your first shot? Also with the grinder, are you single dosing or do you fill the hopper? Depending on how many beans are in the hopper, this could reduce the pressure of the beans being fed into the burrs and therefore affecting the consistency of the particle size distribution.

      Hopefully you'll get some better advice from others. The main thing is to think about all potential variation factors - coffee extraction is a complex process and there are may considerations!

      Comment


      • #4
        Hi coffee hack, thanks for the reply.

        if an extraction is very over or very underextracted I will toss it and won't drink it at all (trying to limit my coffee intake).

        But if it is the general vicinity of 20 - 35s for a 36gm extraction I will drink it.

        The extractions while they taste reasonably similar, I can tell it's suboptimal. I'm also drinking it with a picollo latte / flat white amount of milk so there is a buffer there for poor extraction.

        I will generally heat the machine for at least 30 mins with the filter in the group head, so everything is definitely warmed.

        ​​​​​​While the Technika is a HX, i don't do a pre flush, as it has a PID.

        I also generally single dose my grinder which I understood could be a problem in itself as there not enough pressure from beans in the hopper, however I have a friend with the same grinder who also single doses without the same problems I'm experiencing.

        Comment


        • CoffeeHack
          CoffeeHack commented
          Editing a comment
          Sounds like you're addressing the variables there, so I can appreciate your troubleshooting frustration! If you're single-dosing for each individual shot then at least that process is consistent. Before I got my Niche Zero I would typically load enough beans for two coffees and grind based on the grinder's timer. I did notice the second coffee would pour just slightly faster, and assumed this was because of the inconsistent hopper pressure for the two different extractions.

          Anyway, good luck with nailing down this issue!

      • #5
        I’d try going back to the factory basket if you still have it.
        I have played with an 18g VST with my new machine and find it much more finicky than the stock Lelit one.
        It might not be your issue but is an easy one to check.

        Comment


        • #6
          Originally posted by amberale View Post
          I’d try going back to the factory basket if you still have it.
          I have played with an 18g VST with my new machine and find it much more finicky than the stock Lelit one.
          It might not be your issue but is an easy one to check.
          Hi amberale,
          ​​​​​
          I've been using the VST basket for around 7 years and while I knew about it's reputation for being tricky I never thought to go back to the stock basket when my extractions started becoming noticeably inconsistent.

          As my ECM is new, it will be the first time I've used the ECM basket, I'll give it a go.. thanks!

          Comment


          • #7
            How old are your beans and how do you store them? I suspect they may be stale.
            If you are making 2 coffees a day, 500 grams is going to last you a fair time and could be past their prime as you near the end of the packet.
            Where do you get your beans from, if from a supermarket the quality and age could vary widely.
            You have changed your Espresso machine and the problem continued so it is unlikely to be the machine.

            Maurice

            Comment


            • #8
              I have the IV Profi and have trick that I think helps consistency. If you lift the lever just past the half way mark ( just before the spot which activates the pump), the value will open and the residule pressure in the HX boiler will let a bit of water onto the grinds (with little to no pressure). I only leave it about 5 seconds before going to the full up position and activating the pump. I find the pre-wetting helps with consistency; especially if the bean requires a finer grind.

              That said if I were to bet I'd say your issue is temperature variation ( temperature can effect shot time). I'd guess your first shot is likely hot ( as you don't flush) and your following shots are cooler. I'd try a short flush before the first shot to see if that improves the consistency
              .
              While I don't have a PID; I understand it sets the steam boiler temp; and your group temp is also effected by its environment. ( ie in a breasy cool house or and ACed store the group will be cooler then in a hot kitchen); and the time since the last shot; so just because the PID readout is stable doesn't mean the group temp is stable.

              Comment


              • #9
                Thanks guys.. (email notifications aren't working for me on this forum for some reason).

                Birkin, I buy beans from small roasters (depending on who's running a special at the time); they usually roast to order to ensure freshness.
                Yes you're right, 500gm can last 2-3 weeks, but I would expect the extraction to drop off progressively as the beans aged.

                Maltur, is a cooling flush required for a HX PID? I've read on forums that it is still required, but I saw a YouTube video from Whole Latte Love where they measured brew head temps and said flushing is not required.
                121c is what I set the boiler temp to, and that equates to around 94 at the brew head. What's the general consensus with this? (Cooling flushes on HX PID)

                I've starting keeping a log (only two days old so far).
                I'm not changing anything with my technique or setup for now and seeing what the data shows... So far have had two really short extractions in two days.
                Although I only have two days of data so far, I'm seeing a lot more now that I'm using a naked PF.

                The really short extractions seem to have spritzing, and all the extractions have some degree of channelling (dead spots on the basket).

                I'm starting to think it's a combination of my technique and grinder (the compak K3 has a reputation for clumping). Once i have a few days of data I will change one aspect of my technique to try and address clumping and see whether that helps.
                Last edited by Kit666; 13 February 2021, 09:21 AM.

                Comment


                • #10
                  I would still do a very quick and short flush before the shot regardless of the PID. It’s not necessarily a ‘cooling’ flush and in fact might actually be a ‘warming’ and is really just about ensuring a stable temp and a clean group head. I also wouldn’t take advice from WLL. Some of the stuff I’ve seen on their YouTube channel over the years has been truly awful.

                  Comment


                  • #11
                    What is your puck prep?
                    Do you use a WDT?
                    Do you use a leveller?
                    I have stopped using my leveller for a while and I believe I am getting better, more even extractions.

                    Comment


                    • #12
                      Originally posted by amberale View Post
                      What is your puck prep?
                      Do you use a WDT?
                      Do you use a leveller?
                      I have stopped using my leveller for a while and I believe I am getting better, more even extractions.
                      I'm assuming wdt is the "stir the grinds" method. I have tried that in the past with mixed results (probably didnt do it very well).
                      Yes I use a leveler.

                      A Problem is that I've tried many different methods (and combinations of methods) so much in the past 6 months it was hard to keep track; and only making 2/day its difficult to determine what works.

                      Anyway, now that I'm logging and taking a more methodical approach to testing (only change one variable at a time and run it for a few days to gather results.), I hope to get some more useful troubleshooting info.

                      So far... Humidity does not appear to be a (significant) factor.

                      Comment


                      • #13
                        I got inconsistencies with my M2M Grinder when it was new. I always thought it was just because the burrs are new and it did eventually solve itself. The only other time I get inconsistencies is when I try to single dose causing popcorning in the hopper.

                        Comment


                        • #14
                          Originally posted by yldlj View Post
                          I got inconsistencies with my M2M Grinder when it was new. I always thought it was just because the burrs are new and it did eventually solve itself. The only other time I get inconsistencies is when I try to single dose causing popcorning in the hopper.
                          I've also read that grinder burrs take some time to break in.

                          ​​​​​​POtentially my burrs were worn, creating inconsistency, now that I've changed burrs, it's still inconsistent due to breaking in.. I'll keep on monitoring / keeping my logs!

                          Comment


                          • #15
                            You said you have a friend with same grinder that doesn't have same problems.
                            Ask if you can swap grinders for a week

                            Comment

                            Working...
                            X