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The Value of Flow-control & Pre-Infusion

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  • The Value of Flow-control & Pre-Infusion

    Hi Snobs,

    After a recent discussion on the matter, I've been pondering on the value of flow control, pressure profiling and pre-infusion and I would love to hear from others. To keep things simple, I am grouping these together as flow-control (FC). I would also add that this is aimed at Medium roasted beans typical to what you would get around Melbourne and Sydney and not Ultralight scandinavian 3rd wave hipster goodness.

    Simplistically put, I see 2 theories:

    1. FC provides shot quality improvements
    2. FC provides shot consistency improvements

    Shot quality improvements refer to the idea that with flow control, you can get a shot better than with a flat 9 bar all other things being equal. I do not believe a perfectly dialled in 9 bar shot would be substantially worse than a perfectly dialled in FC shot. The FC shot might be somewhat more clean due to maintaining better puck integrity as a result of pre-infusion and ramping the pressure down at the end of the shot as the buck breaks apart. In a blind taste test, a professional might score the FC shot 5% better than the 9b shot.

    Consistency improvements is the idea that your worst shot will have a higher likelihood of being good. Your shots would be more consistent from shot to shot. The ability to slowly pre-infuse to let the puck expand and the ability to reduce pressure at the end of the shot as the puck loses integrity means you can get a more even extraction. This increases your chances of having a good tasting cup. FC also allows you to bloom and work with fresher beans more easily.

    Somewhat contradictory to the above, one key challenge with manual FC like direct lever, LM GS3MP (not Decent) is that espresso is complex, and you are adding an additional complexity making it hard to be consistent.

    Anecdotally I can add that I have had plenty of amazing shots from both 9b and FC machines.

    Here are some opinions I would like to validate with others:
    1. Does flow control offer better shots than flat 9b? They can, but 9b shots can be just as good provided good puck prep and no channelling.
    2. How much better is the perfect flow controlled shot than the perfect 9b shot? Not much.
    3. Can FC shots be more consistent than 9b shots? Yes, FC shots can reduce channelling and help maintain puck integrity making your worst shot good.
    4. A well experienced barista would do better with a 9b machine than an amateur with FC? Yep.
    5. A well experienced barista would do better with a FC machine than another pro with a 9b machine? Most likely

    I would like to asnwer this question as I feel before I had access to FC, I was convinced that was the missing ingredient to god shots. In reality, I simply lacked tasting and brewing experience.

    Keen on hearing from others

    Happy Friday!

  • #2
    I have a flow control for my ECM Mechanika Profi. It was a Christmas present and I am still on the steep learning curve, however I can offer the following in response to your discussion points.

    1. No, not in my experience unless the beans are past their best.

    2. See 1.


    3. Yes, absolutely. My morning coffee today started a bit fast, so I dialed back the flow and ended up with a great shot.

    4. Not sure. I consider myself an experienced amateur, but I have been making espresso and milk based drinks for about 15 years and I get more bad coffee from cafes than I produce myself regardless of FC.

    5. Maybe.

    Comment


    • #3
      Weeellllll....
      This'll be a deep dive !
      Click image for larger version

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      Comment


      • Ronin
        Ronin commented
        Editing a comment
        How deep do you want to go?

      • EspressoAdventurer
        EspressoAdventurer commented
        Editing a comment
        As deep as you want to go Ron.
        I already do and have for some time 'practiced' flow control via barista inputs.
        And my beliefs that prior to adopting a machine's own form of machine induced 'flow' control the barista needs really to set parameters / taste the outcomes first without the machine first being manipulated.
        Like coffee itself really the parameters are huge!

        Earlier today I was far to preoccupied....so the reason for the gramatic!

    • #4
      yochiya before all of that, how do you drink you coffee? Black or white

      Comment


      • yochiya
        yochiya commented
        Editing a comment
        Great question,

        I drink my coffee in all ways, not kidding.

        Typically, 2 black and 1 white per day. The black is usually espresso or filter (v60). And the white would be a flat white 1/3 espresso, 2/3 milk.

        Milk based hides the nuances you could achieve with FC I'd say.

      • Ronin
        Ronin commented
        Editing a comment
        Ok so for your milk drinks a short pre wet (eg one second) before a normal shot will be enough. You won’t really taste the difference or perhaps will make it washed out

        But you can manipulate the espresso for black coffee better. You can adjust the body, acid content, bitter/sourness and length of shot with flow control.

        This of course will not effect your v60 but the principles of extraction do transfer to alt brewing methods

    • #5
      All of these questions have just one answer….. it depends. And that’s because even though you’ve raised lots of questions and ideas you’re still over simplifying it and leaving out a whole heap of variable. I’m not trying to poo-poo the discussion I’m just saying that it’s the sort of discussion that could just go round and round as there really is no ‘better’ or definitive answer in my opinion.

      Comment


      • Ronin
        Ronin commented
        Editing a comment
        Completely agree

      • Budgiesmuggler
        Budgiesmuggler commented
        Editing a comment
        I actually don’t think this is the case as there are some general principles that apply.

        Light roasted beans are more dense, so need more water contact to extract. They also channel more easily. So if you start from that viewpoint you land on a different answer for control than if you talk about dark roast that will give up its material more easily.

    • #6
      The value of pre-infusion and profiling depends on an individual: if one likes experiment with coffee making & science and art then pre-infusion and profiling have a great value to that individual as both will alter a coffee, but one that wants traditional coffee will see no value in neither.

      Comment


      • #7
        Dialing espresso 101
        Try it of you want but really is just the basics of espresso and how to ageist flavours.
        you are obviously limited by the beans you are using first, type, roast style and solubility.

        Body - adjusted by pressure in the basket, more pressure equals more body
        ​​​​​​ This is in relation to both pump and basket vs coffee mass ratio, and basket type
        Acid - this can be adjusted by temperature, higher temp equals more acid and vice versa. Temp is also relative to flow rate, faster shots equals less temp in
        the basked, slow shots equals more retained heat. Also consider the solubility, more solubility equals faster shots or risk over extraction and vice versa
        Bitter - adjust be temp, too hot or contact time
        Sour - adjust be temp, too cold or contact time

        dry or chalky equals too much temp, adjusted by temp or contact time
        sour or mineraly equals not enough temp, adjusted by temp or contact time

        remember that changing one thing hangers other things.
        happy brewing

        Comment


        • #8
          Another aspect to consider is the difference achievable of a machine equipped with flow control via a temperature controllable boiler and output, vs a standard e61 hx machine with flow control.

          Could some aspects be disguised by body produced by flow and curves getting better bang for buck out of the e61 standard format vs the upper bracket of machines that handles temperature setting eg: decent, Bianca etc

          Comment


          • #9
            Originally posted by Ronin View Post
            Dialing espresso 101 Try it of you want but really is just the basics of espresso and how to ageist flavours. you are obviously limited by the beans you are using first, type, roast style and solubility. Body - adjusted by pressure in the basket, more pressure equals more body ​​​​​​ This is in relation to both pump and basket vs coffee mass ratio, and basket type Acid - this can be adjusted by temperature, higher temp equals more acid and vice versa. Temp is also relative to flow rate, faster shots equals less temp in the basked, slow shots equals more retained heat. Also consider the solubility, more solubility equals faster shots or risk over extraction and vice versa Bitter - adjust be temp, too hot or contact time Sour - adjust be temp, too cold or contact time dry or chalky equals too much temp, adjusted by temp or contact time sour or mineraly equals not enough temp, adjusted by temp or contact time remember that changing one thing hangers other things. happy brewing
            Sometimes. But mostly, it depends.

            Comment


            • Ronin
              Ronin commented
              Editing a comment
              So true

          • #10
            I suggest you read the article I posted the other day - what decent has learnt from lever machines - it deals With this issue. Also some of the decent YouTube videos go deep
            on this. Here is the post: https://coffeesnobs.com.au/forum/cof...lever-machines

            it also depends on what beans you are extracting. It is less of an issue for medium/dark as being less dense they absorb the water more quickly.

            light roasted beans are harder and require more water contact time. Flow control allows good pre- infusion, evenly wet grounds, which means less channeling (taste). Flow control also allows blooming, which increases water contract time and improves extraction (taste). And then also the decreasing pressure holds puck together.

            i would add as a decent owner who can pressure and flow control, is that a small increase in flow has a massive increase on pressure at the puck (it’s something like pressure squared). So if you have manual flow control it’s almost impossible to be repeatably consistent. And it’s to the point where most decent profiles are pressure profile during the extration phase. If you get it wrong it’s very easy to get secondary puck compression which will ruin taste.



            with good control you can evenly extract beans roaster for filter - I exclusively use filter roasts for espresso.

            Last edited by Budgiesmuggler; 19 February 2022, 07:58 PM.

            Comment


            • #11
              I'd be interested in learning more about pressure profiling.

              I've ordered a La Pavoni Specialty Guru which has a Brew Pressure Profile Control. I have found little to nothing online on how to effectively use the La Pavoni brew paddle. However, I'm sure the La Pavoni control mechanism is similar to other models with brew paddles.

              For those with similar brew pressure controls on your coffee machines, what does your workflow look like? For example, in a 21g puck, are you opening up the paddle to 3 bars of pressure for pre infusion until you get your first drops of coffee falling in the cup, before moving the paddle to 9 bars of pressure until you have 35g of output before bringing it back down to 6 bars until you have about 40-42g of output?

              Would love to hear your different approaches and also any useful youtube videos (beyond the Slayer demonstration ones I have found).

              Comment


              • Budgiesmuggler
                Budgiesmuggler commented
                Editing a comment
                Can you shut off all pressure with the paddle?

            • #12
              Originally posted by ElGranEspresso View Post
              I'd be interested in learning more about pressure profiling.

              I've ordered a La Pavoni Specialty Guru which has a Brew Pressure Profile Control. I have found little to nothing online on how to effectively use the La Pavoni brew paddle. However, I'm sure the La Pavoni control mechanism is similar to other models with brew paddles.

              For those with similar brew pressure controls on your coffee machines, what does your workflow look like? For example, in a 21g puck, are you opening up the paddle to 3 bars of pressure for pre infusion until you get your first drops of coffee falling in the cup, before moving the paddle to 9 bars of pressure until you have 35g of output before bringing it back down to 6 bars until you have about 40-42g of output?

              Would love to hear your different approaches and also any useful youtube videos (beyond the Slayer demonstration ones I have found).
              It's still waiting for it in the post! But from what I can see in the few videos online, yes you can shut off the pressure with the paddle: https://www.youtube.com/watch?v=eOc1shF10qE

              Comment


              • #13
                The La Pavoni looks to be the same sort of device as the ECM that I have.

                You can shut off the flow easily. I have been experimenting with the flow control and I can get better consistency (fewer sink shots) by using it to pre-infuse and then slow the shot towards the end, but there are too many variables to have rock solid repeatability.

                Comment


                • #14
                  Originally posted by Dipendente View Post
                  The La Pavoni looks to be the same sort of device as the ECM that I have.

                  You can shut off the flow easily. I have been experimenting with the flow control and I can get better consistency (fewer sink shots) by using it to pre-infuse and then slow the shot towards the end, but there are too many variables to have rock solid repeatability.
                  How are you finding it to use? I saw an interesting video from a Whole Latte Love where they compare a 9 bar pressure shot (with no pre infusion) to a pre infused shot which they only took up to 6 bars to pull the shot. Have you tried this method of not actually hitting the 9 bars? Would be interested in hearing about different experiences using flow control. There doesn’t seem to be much out there…

                  Comment


                  • #15
                    As a decent user I’d try this -

                    start with the paddle 3/4 open for about 5 seconds then shut shut the flow off until you see drips coming from the bottom
                    of the puck - this indicates it’s evenly wet, and the high start flow rate gets it even quickly. Then pull at whatever bar you want.

                    Comment

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