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Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment

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  • Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment

    Grab your favourite brew and be amazed .........


  • #2
    Originally posted by SanderP View Post
    Grab your favourite brew and be amazed .........

    Amazing. Turns the whole extraction conundrum on its head. Wonder how the coffee community will respond to this?


    • #3
      Where is Lyrebird when you need him, to summarise the article into 30 words? I felt like I needed my HP calc to read that.


      • #4
        Haha, 338, me too.

        I read it earlier on Fairfax on line and SBS online as a news story:

        Basically says the scientists working with baristas at St Ali cafe in Melbourne have determined that you should grind coarser, use less water pressure.

        When Stephen Hawking was writing A brief History of Time, his publisher warned him not to use a lot of scientific formulas because they are a turn off for readers and would cost book sales.

        He was right.


        • #5
          A case of my formula is bigger than your perhaps


          • #6
            This is one of the few times that I'm glad I'm a physicist as I read Coffee Snobs :-)


            • #7
              Ugh. I saw Prof Hendon present these results last year and his emphasis was totally different to what has been picked up everywhere.

              The paper says that for a standard 20g/40g yield extraction recipe, it's hard to get extraction yield repeatability of greater than a 1% extraction yield window. It then goes on to suggest that if you grind coarser and extract much faster you can reduce the EY repeatability to produce shots of the target EY with almost no EY variability, but the shots are very fast. It also says that if you grind a little coarser and stop your shots shorter, you can also get the target extraction yield with very little variability, but your shots end up very short.

              What the paper doesn't say is that the alternate ways of getting the same EY result in a better tasting shot, or a shot that tastes the same. In fact, it acknowledges that it will taste different. But I'd bet a lot of money that most of the reporting of this paper will imply that the paper says that the EY equivalent shots all taste the same, or that the fast shots taste better.

              Whether or not one likes the resultant shots is a matter of taste, and one that I'd encourage people to try for themselves and make up their own mind on. If you like the shots, great - you have a good chance of being able to create them repeatably! If you don't like the shots and prefer 20g dose 40g yield, then also great - you have a good data set that shows that it's hard to repeatably get the exact same extraction yield, so you can stop beating yourself up about the occasional sucky shot that you pull!
              Last edited by luca; 23 January 2020, 04:24 PM. Reason: Added more conclusion


              • #8
                Also, if you do try the super fast shots and want to post to tell us about them, please give a little bit more information than good or bad. Please describe how they are different and why you like them or don't. Please also describe what coffee, settings, basket, grind, etc, you used. A pile on of "shot sucks, emperor has no clothes" responses will be entertaining, but we're not going to learn much.


                • #9
                  I put this to the test, I used almost 2kgs and made an absolute mess of my sink and bin.

                  I tried all variations of coarse grinding and 5-7 bar pressure.

                  The result was always coffee, but nothing close to espresso and nothing close to what is consider worthy of drinking, but taste is subjective and someone may want to consume the dirty water I produced.

                  I was upset with myself for believing I was about to save cash and make coffee more quickly and coffee that was better tasting

                  Back to 10.5 bar and 25 seconds for me.


                  • #10
                    Lol; BobSac, I love it how I specifically requested that people describe the things about the coffee that they didn't like rather than just giving their subjective opinion and your response in the very next post was just to give your subjective opinion.

                    To save others who hate the same things that you hate from all of the work, frustration and disappointment that you have gone through, could you describe what sucked about it? Reading between the lines, I'm guessing lower in body, maybe crema too?

                    For what it's worth, I pulled a 45.7g shot from a 15.0g dose at 6 bar in 14s and ended up with an extraction yield of 20.7%, which is in the ballpark of what I was otherwise getting as an EY from this particular coffee. It was obviously much lower in strength, it was pretty sweet, less body, but sort of just tasted a bit washed out, less flavoursome. Also super clean; super low in bitterness. This was just a single shot, not dialled in or anything.


                    • #11
                      Luca so you are not a fan based on the first result?


                      • #12
                        Originally posted by 338 View Post
                        Luca so you are not a fan based on the first result?
                        No, I think my first result was not dialled in, so it's pretty inconclusive, but the important part is this: even at something that you'd think was an absolute and total gusher ... 45 ml in like 15 s ... you actually still end up extracting a pretty similar amount to what you extract in a more orthodox shot. That's actually pretty mindblowing, given that you'd think that if you went that coarse you'd extract far less.

                        If you demand strength in your espresso, then you need look no further. A typical espresso might be 9% strength; this thing was only like 7%. It's dramatically weaker. End of story, but that isn't a surprise - it's exactly what the Matter article says will happen.

                        So it's a question of taste preferences. Here, really the best test would be not as espresso, but to dilute the shots to make long blacks of the same strength. Then you are comparing flavour with flavour.

                        I've been using 15g and trying to pull shots closer to 2.5:1 for a while now; the lower dose was a thing that Jim Schulman pointed out years and years ago and the reason why I bought my latest grinder was largely to enable me to grind fine enough for such shots with very light roasts. I've also successfully pulled Allonge type shots; like 150g in like 50s or something. But what I've never really tried before is 2.5:1 in such a fast extraction time.

                        Damned coffee. I've been making espresso for 20+ years, yet still there's always some entirely new rabbit hole to go down. The super annoying thing, though, is that once you change one thing, you have to reconsider everything else, since it's all interdependent. Eg. is your roast level still good under the new conditions? Eg. that didn't taste good, but would it have been better with a different temperature?


                        • #13
                          I don't know how to describe my shots other than undrinkable or dirty water.

                          It took a while to dial in a grind and grind time to output anything at 6 bar, about 10-12 shots, then I tweaked to improve taste but couldn't anything remotely espresso like.

                          Now that's not a bad thing if you like coffee that is closer to tea than espresso, but I couldn't achieve crema or any body/texture like an espresso.

                          This type of extraction may be best suited to people who like American coffee, Nescafe, cheap pod coffee that gushes, pour over etc. where you have essentially coffee flavoured water.

                          I'm not one to yuk someone's yum, I'm just saying I couldn't achieve anything that resembled an espresso using 6 bar with my setup (HX + Macap M7D).

                          I'm admittedly not a fan of anything that doesn't taste like the traditional Italian espresso, full body, rich, slightly bitter with substantial crema.

                          I'm only one guy with one setup that used one batch of coffee, a lot more testing could be done, I'd like to try a coffee made with this method of it does indeed taste like espresso and I'd be keen to know how it was achieved because saving money and improving taste? Who doesn't want that


                          • #14
                            Originally posted by 338 View Post
                            Where is Lyrebird when you need him, to summarise the article into 30 words? I felt like I needed my HP calc to read that.

                            There ya go! Clear as mud!

                            Admittedly I skimmed through, fascinating... don't know if I can adjust pressure of group head on my machine, but that would be fun to play with..

                            Always love a good research project in coffee!


                            • #15
                              The Short Shot: New Study Challenges Espresso as We Know It

                              This from Roast magazine.

                              "A study that dropped today suggests that coffee purveyors seeking to maximize good taste and consistency have generally been using way too much coffee.

                              The research — led by a 10-member international team performing mathematical modeling and pulling hundreds of espresso shots — suggests that the key to making consistently good espresso is using far less coffee at a coarser grind, with less water and a faster brew time than found in established methods.
                              The recommendations of the study — which boil down to about 15 grams of coffee with shot times from seven to 15 seconds — run contrary to nearly all published standards related to espresso preparation and extraction, including the classic Italian espresso methods and more newfangled approaches from groups like the Specialty Coffee Association."

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                              Sounds like it was written by a bean counter, not a coffee lover, wonder what others thing? cant see myself trying to duplicate their results.