Announcement

Collapse
No announcement yet.

Underextraction vs Overextraction!

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

  • #31
    Originally posted by simonsk8r View Post
    Ah right that's interesting... see I never understood that, and I've seen it written around, but it doesn't make sense to me that plunger-made coffee automatically stops extracting just because it's on the bottom (after one has "plunged" it)... it's still in contact with the water so surely extraction is still occurring... (I know, this is for another thread I'm sure haha but still related to extraction )
    Yeah it's interesting. There's enough people out there now that have experimented with this that it seems to hold water. There's plenty of stuff online about, but for a very easy to understand and follow plunger method see James Hoffmann's 'French Press Updated' video on his YouTube channel.

    Comment


    • #32
      +1 for the James Hoffman video above. Produces consistent results and can be easily fine tuned to produce excellent coffee with a good punch. I set up a recipe for my wife when she was in hospital for a week a couple of months ago, and even her "I'll use less pre-ground coffee today because I only want a weak coffee" mother could use the little container of ground coffee and scale I sent along to make decent coffee in the hospital kitchenette. I won't be doing plunger any other way now!

      Comment


      • #33
        Ah awesome, I'll look into that vid for sure. Havent had plunger in awhile, i might whip it out!

        Still can't comprehend how it stops extracting haha but I'll do some research first. Thanks dudes

        Comment


        • #34
          I'm with you, but that video has me intrigued enough to go pull out the plunger and give it a shot (pardon the pun!), as if not enjoying an espresso drink I’m normally using my Brazen for a scrumptious drip coffee!

          If I understood the video correctly, he has the coffee extracting for a good 9 Mins, a lot longer than I ever let a pot brew for. I’ve been missing out

          Comment


          • #35
            Yeah, so simple to use and makes a tasty brew... wow 9 minutes.. yeah that's wild! XD

            I spent alot of time with the Aeropress in between the time period of my old and new machine, experimented with time left brewing, and there definitely feels like there's a limit with some beans.. [emoji14]

            Comment


            • #36
              Originally posted by simonsk8r View Post
              Yeah exactly, well put! How long the water has been in contact with the coffee.

              That's why a slow flow results in over extraction AND so does a normal shot that has been left too long. Both have been in contact for far too long and extracted too much out of the coffee.

              And why a fast flowing shot results in underextraction AND so does a shot that may be normal flow but was cut off too early. Both have not extracted enough solids.

              (Sorry, am moreso writing this as a summary for myself to fully understand XD)

              Like you said before:
              Yes, that's exactly right.

              Use the following rules of thumb for espresso:

              under extraction - shot is sour - flow too fast (and/or channelling), yield (shot volume) too low, bad tamper, water too cold
              over extraction - shot is bitter/astringent - flow too slow, yield too high, water too hot

              As it says, strength and extraction are related but not the same - you can have strong coffee that is under extracted and weak coffee that is over extracted - see the universal brewing control chart example here with these areas labelled.

              Comment


              • #37
                Ah that's brilliant, thanks so much for that, will study that like crazy.

                Hmm, I can understand how something can be underextracted and strong (stopping a shot really short, much less diluted), and overextracted but weak (a shot left going far too long), but the chart doesn't seem to be displaying that...

                The green diagonal line seems to suggest that the longer you leave a shot the stronger it gets ad infinitum...

                Also I've never quite understood the difference between TDS and extraction...

                Total Dissolved Solids sounds like it should be what you're "extracting" from coffee (between the ideal 18-22%), yet it seems to be a different figure/equation altogether...

                According to the graph, TDS seems to describe weak--->strong, whereas extraction seems to describe amount of flavour components in coffee as the shot progresses...

                Am I on the right track in any sense at all? Haha...

                Comment


                • #38
                  Originally posted by simonsk8r View Post
                  Ah that's brilliant, thanks so much for that, will study that like crazy.

                  Hmm, I can understand how something can be underextracted and strong (stopping a shot really short, much less diluted), and overextracted but weak (a shot left going far too long), but the chart doesn't seem to be displaying that...

                  The green diagonal line seems to suggest that the longer you leave a shot the stronger it gets ad infinitum...

                  Also I've never quite understood the difference between TDS and extraction...

                  Total Dissolved Solids sounds like it should be what you're "extracting" from coffee (between the ideal 18-22%), yet it seems to be a different figure/equation altogether...

                  According to the graph, TDS seems to describe weak--->strong, whereas extraction seems to describe amount of flavour components in coffee as the shot progresses...

                  Am I on the right track in any sense at all? Haha...
                  You need that book I mentioned Simon. It's explained really simply and clearly in it. I'm still happy to lend it to you if you're interested.
                  Otherwise you'll find all the same info in this section of the Batista Hustle archives - https://baristahustle.com/blogs/bari...ged/extraction

                  The only real issue with the BH stuff is that it's kind of conversational and therefore a bit wordy and harder to follow. But if you read each of the sections carefully from oldest to newest you'll get the picture.

                  Comment


                  • #39
                    The analysis at Home Barista in the link below is also very well explained:

                    https://www.home-barista.com/espress...tractions.html

                    Comment


                    • #40
                      Thanks heaps Leroy, yeah I plan on buying that one for sure. Yeah BH I've found is great, yeah can get sometimes a little wordy, but overall I love everything it's about. Perger pulls no punches and isn't afraid of getting in there and experimenting and exploring all things coffee. I haven't seen many getting so involved and even his recent distribution tool project is awesome

                      Comment


                      • #41
                        Originally posted by Barry O'Speedwagon View Post
                        The analysis at Home Barista in the link below is also very well explained:

                        https://www.home-barista.com/espress...tractions.html
                        Thanks Barry I've read that but will read through again, cheers

                        Comment


                        • #42
                          Originally posted by Leaf_Bean_Machine View Post
                          Yes, that's exactly right.

                          Use the following rules of thumb for espresso:

                          under extraction - shot is sour - flow too fast (and/or channelling), yield (shot volume) too low, bad tamper, water too cold
                          over extraction - shot is bitter/astringent - flow too slow, yield too high, water too hot

                          As it says, strength and extraction are related but not the same - you can have strong coffee that is under extracted and weak coffee that is over extracted - see the universal brewing control chart example here with these areas labelled.
                          FYI - Espresso is WAAAY off the scale of that chart.

                          18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
                          3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS

                          -----

                          In my opinion, extraction is one of the most misunderstood concepts in specialty coffee (second perhaps to the relationship between pressure and flow).


                          I think it is important to distinguish the extraction rate from the espresso flowrate:
                          • extraction rate is the rate mass is transferred from the coffee to the water in the basket.
                          • espresso flowrate is, rather obviously, the rate that mass is leaving the basket (water + coffee)



                          Why is this useful?


                          The ratio of extraction rate / espresso flowrate determines the concentration of the liquid leaving the basket at any given time. The average of this over the duration of the shot is equal to the mass extracted / espresso mass - which is the espresso concentration (i.e. TDS), as the calculation above demonstrates.


                          All else being equal, the extraction rate slows as the amount of soluble material left in the puck decreases (i.e. as the shot progresses). Meanwhile, the espresso flowrate increases at the same time. The net result is seemingly obvious - the concentration of the liquid leaving the basket decreases during the shot and the espresso concentration must decrease along with it.


                          But that isn't the whole story. We can't just dilute a ristretto to make an espresso, right?


                          Well, as I mentioned above, the extraction rate slows as the amount of soluble material in the puck is depleted. But not all components extract at the same rate. The dissolution rate of a given component likely depends its solubility and how much of it there is. Highly soluble components would therefore dissolve fastest (possibly completely) and would make up a greater part of the composition at the beginning of the shot. The less soluble compounds would dissolve at a slower rate but may make up a greater fraction of dissolved solids later in the shot.

                          Comment


                          • #43
                            Originally posted by MrJack View Post
                            FYI - Espresso is WAAAY off the scale of that chart.

                            18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
                            3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS
                            I would have thought 18g is a double meaning the espresso shot will be closer to 60g hence the TDS is ballpark correct

                            Comment


                            • #44
                              Originally posted by saeco_user View Post
                              I would have thought 18g is a double meaning the espresso shot will be closer to 60g hence the TDS is ballpark correct
                              12% is the upper limit really of well made espresso. The range is along the lines of 8-12%. There would be a few exceptions. Let's pick one:

                              Sensory Lab for example recommend a brew ratio of 3:1 for espresso for some of their coffees. So in cases like this you're looking at -

                              20% extraction yield from 20g of coffee = 4g

                              4g in a 60g espresso = 6.6%.

                              To me that's about as low as you can go and still call it espresso. A good lungo extraction will be lower, but lungos are a fine art and aren't really true espresso so I won't include them.

                              Comment


                              • #45
                                Originally posted by MrJack View Post
                                FYI - Espresso is WAAAY off the scale of that chart.

                                18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
                                3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS

                                -----

                                In my opinion, extraction is one of the most misunderstood concepts in specialty coffee (second perhaps to the relationship between pressure and flow).


                                I think it is important to distinguish the extraction rate from the espresso flowrate:
                                • extraction rate is the rate mass is transferred from the coffee to the water in the basket.
                                • espresso flowrate is, rather obviously, the rate that mass is leaving the basket (water + coffee)



                                Why is this useful?


                                The ratio of extraction rate / espresso flowrate determines the concentration of the liquid leaving the basket at any given time. The average of this over the duration of the shot is equal to the mass extracted / espresso mass - which is the espresso concentration (i.e. TDS), as the calculation above demonstrates.


                                All else being equal, the extraction rate slows as the amount of soluble material left in the puck decreases (i.e. as the shot progresses). Meanwhile, the espresso flowrate increases at the same time. The net result is seemingly obvious - the concentration of the liquid leaving the basket decreases during the shot and the espresso concentration must decrease along with it.


                                But that isn't the whole story. We can't just dilute a ristretto to make an espresso, right?


                                Well, as I mentioned above, the extraction rate slows as the amount of soluble material in the puck is depleted. But not all components extract at the same rate. The dissolution rate of a given component likely depends its solubility and how much of it there is. Highly soluble components would therefore dissolve fastest (possibly completely) and would make up a greater part of the composition at the beginning of the shot. The less soluble compounds would dissolve at a slower rate but may make up a greater fraction of dissolved solids later in the shot.
                                Spot on. Gee I wish I was able to explain things as well as that. I understand all that, but certainly couldn't put it into words like you have. This is all the stuff that the DE machine is delving into which is what makes it kind of exciting.

                                Comment

                                Working...
                                X