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Variation in shot time (newbie)

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  • Variation in shot time (newbie)

    Dear all,

    Lurking around for a few weeks and trying to make espresso at home for a while now with very mixed results. I've read numerous pages on dialing in, espresso making and machine maintenance in general but can't seem to get my shot times right. Below my equipment and data/observations:

    Machine: Rancilio Silvia with PID (warm up on timer 10-15 min before brewing)
    Grinder: Kompak K3 (bought second hand, taken apart and cleaned, burrs still felt sharp)
    Dosage: 17 grams in Silvia double basket (I pre grind maybe 8 grams of beans and discard that grind, after that I weigh out +/- 17.3 grams and take coffee out of portafilter till I hit 17 grams exactly)
    Scale: precision scale used for hops in my beer brewing ;-), check consistency with standard Aussie coin
    Beans: used different varieties, all fresh (within 1-2 week of roasting date)
    Distribution: WDT and OCD knockoff
    Tamp: Easytamp (calibrated)

    I've checked machine flowrate for consistency and it is fine.

    I know I'm new to this but would like to get more consistent, any tips for this newbie? Any information you're missing?

  • #2
    The information that's missing is what's inconsistent and by how much

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    • #3
      How do the shots taste?

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      • #4
        Yes, as Ninja says, what are you finding inconsistent about the times?

        You are consistent in weight. Good. The other 2 variables are the grind and the tanping pressure. Weight and pressure are two constants, so do your 17 or so grams and tamp to about 14 kg pressure.

        Having converted those two variables into constants only then turn to how fine or coarse you should grind to achieve the desired and consistent shot time.

        Discarding that much ground coffee seems an awful lot of expensive unnecessary waste. Can't you empty out as much retained grounds after each dose and take ut from there?

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        • #5
          I've never used a K3 but with one of my previous grinders I found that grind size/uniformity was terrible when I weighed out beans and just ground those. It seemed the like the popcorn effect and lack of weight pushing down on beans resulted in inconsistent output. So you might want to experiment with adding more beans in the hopper and weighing the grinds in PF (only). This is more work as you might need to remove excess beans out of the hopper (a pain) and then store them appropriately. You may already be doing this but it wasn't clear from your post.

          Comment


          • #6
            Thanks for the replies, below my response which hopefully captures what was missing:
            Shot times: vary between shots sometimes 10 seconds. So I brew a 1:2 ratio, making 34 grams espresso out. I'm always within 1 gram of yield. Example: last nights shot and this mornings (25.87 seconds versus 36.68 seconds with a difference in yield of 0.87 grams)
            Taste: when I'm in the 25 to 30 second range for a 34 gram yield taste is good, nice body and full flavours. Anywhere over or under it generally isn't really nice.
            Tamping pressure: I'm using a Eazytamp with calibrated spring so pressure should be fairly consistent
            Weighing: I weigh out around 17.6 grams off coffee going into the hopper, grinding in basket and then removing any excess by a small spoon. (figured because I do WDT it wouldn't matter too much if the spoon creates a disturbance.
            Purging: will look for different methods of getting the "old" coffee out. Only started doing this recently to see if it made a difference in consistency.
            Bean storage: I use one of those "air tight" lunch boxes, keep it stored in my cabinet (dark) and relatively cool

            Comment


            • #7
              Originally posted by Nevsmantis View Post
              Thanks for the replies, below my response which hopefully captures what was missing:
              Shot times: vary between shots sometimes 10 seconds. So I brew a 1:2 ratio, making 34 grams espresso out. I'm always within 1 gram of yield. Example: last nights shot and this mornings (25.87 seconds versus 36.68 seconds with a difference in yield of 0.87 grams)
              Taste: when I'm in the 25 to 30 second range for a 34 gram yield taste is good, nice body and full flavours. Anywhere over or under it generally isn't really nice.
              Tamping pressure: I'm using a Eazytamp with calibrated spring so pressure should be fairly consistent
              Weighing: I weigh out around 17.6 grams off coffee going into the hopper, grinding in basket and then removing any excess by a small spoon. (figured because I do WDT it wouldn't matter too much if the spoon creates a disturbance.
              Purging: will look for different methods of getting the "old" coffee out. Only started doing this recently to see if it made a difference in consistency.
              Bean storage: I use one of those "air tight" lunch boxes, keep it stored in my cabinet (dark) and relatively cool
              Just brewing my morning shot, 4 seconds difference between today and yesterday's with same 34.0 gr yield. Any more ideas?

              Comment


              • #8
                It could be a few things. I would suggest not using the OCD knock off, especially after doing WDT. Also beans should be stored in a container with a one-way valve (e.g. the bag they come in) not just in an air tight container. If you want them in the container leave them in the bag and squash all the air out, took the bag up and then put that in the container.

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                • #9
                  Originally posted by level3ninja View Post
                  It could be a few things. I would suggest not using the OCD knock off, especially after doing WDT. Also beans should be stored in a container with a one-way valve (e.g. the bag they come in) not just in an air tight container. If you want them in the container leave them in the bag and squash all the air out, took the bag up and then put that in the container.
                  Will test both (one at a time). Just for me to understand why would keeping beans in an airtight container (without) a one way valve create variation in shots?

                  Comment


                  • #10
                    Have a read here: https://coffeesnobs.com.au/roasted-b...ted-beans.html


                    Java "Little things matter more than you may think" phile
                    Toys! I must have new toys!!!

                    Comment


                    • #11
                      This may not help you, but just an observation: if the beans are still too fresh, and in an airtight container, they cannot degass their carbon dioxide. The gas does interfere with water absorption during extraction. Hence the need for storage in one-way valve containets at least in the week after roasting.

                      You are weighing out 17.6 grams of beans to extract 34 grams of coffee. A few of those grams would be retained in the grinder. So you are really getting that amount of brew from...I don't know...13 or 14 grams or less?

                      That would be way too thin I would guess. Best to pop about 20 grams or so in the hopper, and weigh the 18 or so resultant grounds after they are in the loaded portafilter.

                      I have never gone for fancy distribution methods in the basket. Just load it, flatten the mound with a finger and tamp.

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                      • #12
                        I do 250g in the Hottop roaster at a time yielding probably 200g and I keep three airtight containers of beans and use them in rotation. I keep them by the machine at room temperature.

                        No issues with shot variation time. I don't single dose either on the Robur...just keep beans filling the neck(bottom) of the hopper to be consistent then dose volumetrically (to the top), smooth with finger and tamp. I don't purge ever as I use it daily.

                        Whatever you do, just be consistent.

                        I have done it this way for years. I guess if I had a problem I'd ask for advice or experiment and change the way I do things. Now the Robur is a conical and they are very forgiving of variation. I adjusted it yesterday for the first time in two weeks, about 1mm movement finer on the dial.

                        It might be a matter of managing your expectations too. A few seconds either way is not going to make a good shot bad. Perfectionism can ruin a good experience if the expectations are not reasonable.
                        Last edited by wattgn; 22 October 2019, 10:18 PM.

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                        • #13
                          Originally posted by wattgn View Post
                          Perfectionism can ruin a good experience if the expectations are not reasonable.
                          This!! the most important measure is taste in the cup. If you like it, all is good

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                          • #14
                            I've been taught the "palm taps" method for settling the coffee grind bed. It's simple enough and just works.

                            https://www.fivesenses.com.au/blog/l...-distribution/

                            With a nice fitting 58mm dosing cup, I tip it over and give it a nice whirl(?? ) and then do the palm tap.

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                            • #15
                              Hi guys, been a while and have taken your advise to heart. Have started to not do the OCD knockoff and keep the beans in the original bag (new 500gr EspressoWow from CS).

                              Unfortunately not relief, shots differ significantly, beans were roasted 30 Oct. I'm a bit taken back by this and need to go back to the drawing board.

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