Page 1 of 2 1 2 LastLast
Results 1 to 50 of 53
Like Tree52Likes

Thread: Underextraction vs Overextraction!

  1. #1
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494

    Underextraction vs Overextraction!

    Hey guys, just moved this topic to a thread of its own. I've researched around a bit and found differing descriptions.. So moreso a varied semantics thing (which term for what type of extraction), and also varied end result (flavours/acids/bitters etc). Included Barry's response (hope that was ok!).

    And yeah I may have moreso described 'signs of', and mixing it with 'causes of', but hopefully it's understood what I'm getting at.


    [quote name="simonsk8r" post=612545]Speaking of vocab, was actually going to start a thread regarding underextraction vs overextraction, but fitting to put it in here! (Thanks Otago, but sorry for hijacking :S..)

    Cannot for the life of me find a definitive answer anywhere...
    I keep seeing these terms being interchanged. I know what each is (if I stick with one understanding relatively speaking!).
    It's moreso the terms themselves I've seen:

    Underextraction= too fast a flow/extraction, not extracting the coffee properly as the water-coffee contact time is too short. Contradictory flavour indicators too: will result in too flat, sour, bitter (I've also seen a faster flow being described as flat in some places, sour on others, and bitter in others.....which I'd love if someone clarified? Experience-wise I've found all three to occur... an Ethiopian bean I've had alot of sourness from a fast flow/larger yield, alot of bitterness from Indian, and flatness from others...)

    Overextraction= far too slow a flow/extraction, too high contact time, have seen descriptions of harsh, sour, acrid/astringent, also seen bitter described for these shots...

    To me this makes sense (the flow rate moreso, not flavour descriptions..), but I've seen the opposite said. That underextraction is that the flow is too slow hence coffee being 'underextracted', and overextraction having too much water flow through the coffee hence overdoing it, which also sort of makes sense..

    Just trying to get clarification on the terms, but also the end result (which I'm feeling may be more dependent on the bean characteristics than generic flavour outcomes for all coffee...). Even after all these these of coffee-ing I'm still confused haha..

    Thanks so much guys!

    Simon[/QUOTE]

    Quote Originally Posted by Barry O'Speedwagon View Post
    Probably better starting a separate thread. You seem to be confusing factors that may cause under/over extraction, with what under/over extraction is. As I understand it, under/over extraction refers to the extent to which the solubles in the ground coffee are extracted in the brewing process and land in your cup. Under-extracted coffee is more acidic as the those flavours are extracted more easily. Yes, that may result from too quick a pour (or too coarse a grind or......). The best indicator of whether coffee is over or under extracted is the taste.
    degaulle likes this.

  2. #2
    Member
    Join Date
    Dec 2016
    Location
    Netherlands
    Posts
    77
    As I have understood it, both over-and underextraction are characterized by an unbalanced taste profile. When a shot is underextracted, the intense flavors from a bean (which may be fruity/acid and/or bitter/nutty) are insufficiently balanced by sweetness obtained by the extraction of caramels. Depending on the variety/origin/roast the overall impression of such a shot can be either sour or bitter. Too coarse a grind setting may be the root cause, but also channeling or too cool a grouphead.
    At overextraction, the dry distillates (the least-wanted from the bean) become more prominent and overextracted shots I had on occasion I would describe as dull-bitter or ashy. The darker the roast, the more ashy an overextracted shot tastes. My impression is that with machines that allow you to control / extend the amount of low pressure pre-infusion, you can run slower shots overall before they become overextracted. With fixed speed pump machines that do not offer such controlled LP preinfusion other than an inherent pressure ramp-up, the sweet spot lies with somewhat faster flowing shots.
    simonsk8r likes this.

  3. #3
    Senior Member Yelta's Avatar
    Join Date
    Jun 2009
    Location
    Moonta SA.
    Posts
    5,189
    Over/under extraction is subjective, one persons over/under may well be a god shot to others.

    30 ml in 25/30 seconds is a guide only, it should get you well and truly into the ball park, from there its all about experimentation, use some beans and vary extraction times using your standard dose, the flavours you enjoy/dislike will quickly become evident.

    We can discuss the terms ad infinitum on the forum, these terms will still remain a mystery to many, taste and experience are by far the best teachers.
    simonsk8r likes this.

  4. #4
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600

    Underextraction vs Overextraction!

    Yes extraction is actually a measurable outcome (with the correct equipment) as it's the amount of dissolvable coffee solids that end up in the cup. It's a result of the level of contact the coffee has had with water while brewing which is determined by time and/or the volume of water used.
    Obviously we're not going to check every coffee we make with a refractometer so whether a drink is under or over extracted is usually decided by taste. I get what Yelta is saying that this is somewhat subjective, although I'd add that this is within an acceptable range (which I'm sure is what Yelta meant). Seriously under or over extracted coffee isn't going to be enjoyable to anyone, no matter what your preferences. The biggest mistake people make is that they confuse sourness and bitterness. This is common and isn't only related to tasting coffee. So to be clear under extracted coffee can be sour, but never bitter and over extracted coffee can be bitter but never sour. Work out the difference between these two flavour traits and you'll be able to detect under or over extracted coffee much more easily.

  5. #5
    Senior Member
    Join Date
    Feb 2011
    Posts
    296
    As Leroy said, it is determined by how much coffee solids are extracted. Coffee has ~30% soluble solids by mass. We want to extract 18-22% of those into our cup. Above 18-22% =over extraction, and under 18-22% =underextraction.

    In espresso, flow rate and total extracted volume go hand in hand. So you can't just look at how fast or how slow the flow is, independent from how much total water is through. The trend is : high flow rate = lower extraction rate = less extracted solids per ml water, and vice versa. Water is the solvent, so the more water is through the puck, the more you extracted.

    Under-extraction : Not enough solids was extracted. Scenarios : (i) flow rate is slow/ok but not enough water through. ie. only 10ml water flow through puck in 30s, or 10ml in 10s. (ii) flow rate too high (very low extraction rate per ml water). ie. 80ml water flow through coffee in 10s (iii) puck channelling : flow rate is ok, 30ml in 30s. But some portion of the puck is dry/not extracted, thus not extracted properly.

    Note that if you grind too fine, the flow rate can get too slow (supposedly higher solids extracted per ml) but channelling starts happening (you see more dead/dry spot with a bottomless portafilter) so you end up with underextraction.

    Over extraction : Too much solids was extracted. Scenario : (i) flow rate was ok/slow, but too much water was drawn. 30ml water flow through coffee in 60s, or 80ml water through coffee in 40s.

    Note that the numbers are approximate/chosen randomly just to deliver the point.


    Typically it is much harder to over extract and underextraction is more common place.

    To identify extraction via bitter/sour can be a bit more murky. Typically sour=underextracted,bitter=overextracted. But with coffee roasted so light nowadays, the coffee may taste extremely sour to some even if it is overextracted. Some improperly roasted coffee (too light or too dark) can also taste bitter if under extracted.
    Dimal, Magic_Matt and simonsk8r like this.

  6. #6
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    @degaulle: Ah that makes sense, that's what made sense to me, underextracted will show up AS water flowing too fast through (from either too coarse, channeling, low temp etc), and flavour will be too sour OR bitter depending on bean.

    I'd say sourness would be more prominent, would you say too much bitterness comes through only when a shot is left pouring for far too long (that is, it may be a normal good flow, but cut off too late as opposed to a gusher/underextracted shot)? Pieces coming together now haha...

    And overextracted being far too slow and somewhat too harsh and the bitter component being emphasised.

    This is what I've trying to understand (and I've been at this for an odd 8 years now...), just the proper definition and the outcome. I've seen the definitions reversed (underextr resulting from too slow etc), and also the flavour outcomes reversed (too fast equals bitterness or sourness, too slow equals bitterness or sourness...).
    But I'm thinking people may be referring to when shots are cut off also and using some terms a bit willynilly...

    @Yelta: Good points, and definitely appreciate your thoughts. But I guess I'm not aiming at defining what people like as such subjectively, but the definite outcomes of under/overextraction, and the definitions that are used. Like baking a cake for faaaar too long will definitely have certain flavour results, even if people may like that or not.
    But true in that the end result is what matter and what one prefers, I've enjoyed shots that have lasted a minute, and also ones that lasted 15 seconds haha. Just flavour outcomes and proper definitions as to exactly what under/overextraction means not only the signs of it, but the flavour result.

    @LeroyC: Yeah great points there.. Definitely sour and bitter get mixed up, and has to do with not only sensation and flavour, but positioning on the tongue huh. Time to pull some 4 minute long 20ml shots, and some 15s 200ml shots and get tasting 😄

    @samuellaw178: Thanks for that, great point about not only flow rate being important, but total water volume put through (for sure cutting a fastflowing shot at 15s as opposed to cutting it at 40s is going to be to fairly different drinks...)

    Yeah that's made me think...
    So we can ballpark it as such:

    Both under and over extraction is dependent not only on flow rate, but also volume of water put through.

    So

    -fast flowing shot or stopping shot too short (even if it's a slowflowing shot) are both underextracted (BECAUSE in both cases we've achieved less than 18% solubles dissolved)
    =generally too sour, flat

    -slowflowing shot or stopping a shot far too late is overextracted (BECAUSE in both cases we've achieved more than 22% solubles dissolved)
    =generally too harsh, bitter

    Would that be fair to say? Wow, am blown away thanks so much for your answers guys, in a way I knew this but it didn't really click fully until it was explained in that way... (not to mention many years of seeing different terms thrown around and different things described, and my lack of wrapping my head around it moreso haha)

  7. #7
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600

    Underextraction vs Overextraction!

    Quote Originally Posted by simonsk8r View Post
    @degaulle: Ah that makes sense, that's what made sense to me, underextracted will show up AS water flowing too fast through (from either too coarse, channeling, low temp etc), and flavour will be too sour OR bitter depending on bean.

    I'd say sourness would be more prominent, would you say too much bitterness comes through only when a shot is left pouring for far too long (that is, it may be a normal good flow, but cut off too late as opposed to a gusher/underextracted shot)? Pieces coming together now haha...

    And overextracted being far too slow and somewhat too harsh and the bitter component being emphasised.

    This is what I've trying to understand (and I've been at this for an odd 8 years now...), just the proper definition and the outcome. I've seen the definitions reversed (underextr resulting from too slow etc), and also the flavour outcomes reversed (too fast equals bitterness or sourness, too slow equals bitterness or sourness...).
    But I'm thinking people may be referring to when shots are cut off also and using some terms a bit willynilly...

    @Yelta: Good points, and definitely appreciate your thoughts. But I guess I'm not aiming at defining what people like as such subjectively, but the definite outcomes of under/overextraction, and the definitions that are used. Like baking a cake for faaaar too long will definitely have certain flavour results, even if people may like that or not.
    But true in that the end result is what matter and what one prefers, I've enjoyed shots that have lasted a minute, and also ones that lasted 15 seconds haha. Just flavour outcomes and proper definitions as to exactly what under/overextraction means not only the signs of it, but the flavour result.

    @LeroyC: Yeah great points there.. Definitely sour and bitter get mixed up, and has to do with not only sensation and flavour, but positioning on the tongue huh. Time to pull some 4 minute long 20ml shots, and some 15s 200ml shots and get tasting

    @samuellaw178: Thanks for that, great point about not only flow rate being important, but total water volume put through (for sure cutting a fastflowing shot at 15s as opposed to cutting it at 40s is going to be to fairly different drinks...)

    Yeah that's made me think...
    So we can ballpark it as such:

    Both under and over extraction is dependent not only on flow rate, but also volume of water put through.

    So

    -fast flowing shot or stopping shot too short (even if it's a slowflowing shot) are both underextracted (BECAUSE in both cases we've achieved less than 18% solubles dissolved)
    =generally too sour, flat

    -slowflowing shot or stopping a shot far too late is overextracted (BECAUSE in both cases we've achieved more than 22% solubles dissolved)
    =generally too harsh, bitter

    Would that be fair to say? Wow, am blown away thanks so much for your answers guys, in a way I knew this but it didn't really click fully until it was explained in that way... (not to mention many years of seeing different terms thrown around and different things described, and my lack of wrapping my head around it moreso haha)
    Simon I have a really good book that you're welcome to borrow if you like that explains all this stuff really well (photo of cover shown below). In the past I'd read plenty of stuff online by the likes of Hoffmann, Perger etc and had a basic understanding but had never quite wrapped my head around how something could be under extracted and strong or over extracted and weak.
    The way it's explained in this book is much the same, but for some reason it's done in a way that worked for me so it might do for you too. Like you I've been doing this coffee thing for 8-10 years and I'm still learning. I read this whole book front to back and while a lot of it was stuff I already knew it was an easy and enjoyable read.
    The author is a true coffee snob and pulls no punches in this area. He is always very clear about when things he's expressing are his personal opinion though, so he doesn't come off as being 'holier than though'. It's a nice book that's well presented, the only thing that lets it down is a few too many typos which is a shame. Anyway if you're interested send me a PM with your address and I'll send it your way.

    Last edited by LeroyC; 23rd July 2017 at 06:51 PM.
    Crema_Lad and Magic_Matt like this.

  8. #8
    Senior Member Crema_Lad's Avatar
    Join Date
    Dec 2008
    Location
    Melbourne, Victoria, Australia, Australia
    Posts
    174
    Quote Originally Posted by LeroyC View Post
    The way it's explained in this book is much the same, but for some reason it's done in a way that worked for me so it might do for you too. Like you I've been doing this coffee thing for 8-10 years and I'm still learning. I read this whole book front to back and while a lot of it was stuff I already knew it was an easy and enjoyable read.
    The author is a true coffee snob and pulls no punches in this area. He is always very clear about when things he's expressing are his personal opinion though, so he doesn't come off as being 'holier than though'. It's a nice book that's well presented, the only thing that lets it down is a few too many typos which is a shame. Anyway if you're interested send me a PM with your address and I'll send it your way.
    Ha might need to become a bit of a chain mail thing, sounds like a good read!

    Some good questions Simon, and great input on something I too have been but trying to fully appreciate yet also I fear mistaking sour/bitterness as one and the same. Every 'bad' shot I've tasted this far i would describe as 'sour' vs bitter - but sure I've encountered a few of the latter

    Heck I've even been offered a shot from experienced coffee snobs Only to exclaim 'ugh, it's sour' yet they've been shocked when having a shot from the same pour and thinking its spot on. It's left me thinking my taste buds are pretty mixed up if I don't know a 'good' shot when I'm tasting one

  9. #9
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Ah thanks so much Leroy that's very kind of you I'll let you know if am keen, what was the title of the book? May just end up buying it as a good reference to have if it's stuff with a good knowledge base!

    Ahh Crema_Lad I know what you mean hey, and the thing is, no one will EVER know what another person is subjectively tasting, I think I brought that up as a topic when I was studying philosophy at uni, that we could be tasting (even seeing etc) completely different things but be arbitrarily describing something based on our reference point only. We use the same term, and could be experiencing something completely different, but we're using our perceptive reference point, and still be in agreeance. (Of course some loopholes could be explored haha).

    I might work more on palette refinement, cupping was never a strong point for me. I might research and buy one of each: the most bitter food possible, sour, sweet etc etc, just to REALLY drill it in haha

    And I actually don't think sourness is an unpleasant as such, it's when it's overbalanced and overdone in that direction when it's overkill I reckon. The delightful sourness of lemon water as opposed to straight biting into a lemon haha
    Crema_Lad likes this.

  10. #10
    Senior Member level3ninja's Avatar
    Join Date
    Nov 2013
    Location
    Casula, NSW
    Posts
    526
    The punch of straight espresso is easy to mistake for sourness if you aren't regularly drinking straight espresso
    Crema_Lad, shewey and 338 like this.

  11. #11
    Senior Member Crema_Lad's Avatar
    Join Date
    Dec 2008
    Location
    Melbourne, Victoria, Australia, Australia
    Posts
    174
    Thanks, that's making sense level3ninja!! I am normally a milk based drinker, but getting to know my new machine I've been tasting the shots and I think that initial 'always sour' impression is dissipating somewhat as I'm getting a little more accustomed to the taste of a straight shot. Just today I tried one which was a little sour-ish but I could taste other notes beyond that. I've also had some shots where sour doesn't come into the descriptive, even had one where I could taste distinct marzipan notes and another berries.

    Exciting progress, sadly not consistently replicating the experience which is what I continue to work on!

    @Simon, yes I agree it's s good idea to fine tune the tastebuds of sour vs bitterness to apply back to our espresso quest! I actually quite like sour and could easily suck away on a raw lemon, but not so keen on my coffee tasting that way!
    Last edited by Crema_Lad; 23rd July 2017 at 08:13 PM.
    level3ninja likes this.

  12. #12
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote Originally Posted by simonsk8r View Post
    Ah thanks so much Leroy that's very kind of you I'll let you know if am keen, what was the title of the book? May just end up buying it as a good reference to have if it's stuff with a good knowledge base!
    Sorry, I forgot to insert the cover shot in my post. I've added it now - it's called 'The Curious Barista's Guide to Coffee'.
    Crema_Lad likes this.

  13. #13
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Ah thanks for that mate I'll look into it

  14. #14
    Senior Member Crema_Lad's Avatar
    Join Date
    Dec 2008
    Location
    Melbourne, Victoria, Australia, Australia
    Posts
    174
    Quote Originally Posted by LeroyC View Post
    Sorry, I forgot to insert the cover shot in my post. I've added it now - it's called 'The Curious Barista's Guide to Coffee'.
    Quote Originally Posted by simonsk8r View Post
    Ah thanks for that mate I'll look into it
    If you search for it on Amazon.com, it has a 'look inside' feature that lets you preview some sections, maybe enough to give you a feel for its overall content.

  15. #15
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Cheers yeah it looks like it'd be quite a read. Never read any official coffee books, only online stuff, might be an idea
    LeroyC likes this.

  16. #16
    Site Sponsor SpiceBean's Avatar
    Join Date
    Nov 2015
    Location
    Wentworth Falls
    Posts
    44
    In my training and experience in cafes, over extracted means the grind is to fine so the yield is low and the flow is overly slow, the flavours associated with this is in general bitter. Under extracted is the opposite, so too coarse a grind and flow too watery and fast, flavour profile being sour.

    Of Course these are generalisations. Its best to start with your 30seconds/22grams for 60mls as a starter, then adjust grinder and yield after experimentation.

    Mike
    Crema_Lad, simonsk8r and degaulle like this.

  17. #17
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Thanks Mike, yeah that was definitely my initial understanding, but kept reading opposite usage of the terms (which also did make sense in a way), much was clarified in this thread (and hopefully for others too!)
    SpiceBean likes this.

  18. #18
    Member
    Join Date
    Jul 2014
    Posts
    95
    There's often a marked saltiness with under extracted coffee too. The old learning technique of divided a shot time wise into 3 or 4 can be enlightening.
    Crema_Lad, simonsk8r and LeroyC like this.

  19. #19
    Member
    Join Date
    Jul 2014
    Posts
    95

    Underextraction vs Overextraction!

    (Although the total subjectively isn't quite the same as the sum of the parts)
    LeroyC likes this.

  20. #20
    Member
    Join Date
    Dec 2016
    Location
    Netherlands
    Posts
    77
    The test of thirds (or quarters If you like) always intrigues me: the general concept too slow = bitter, too fast = sour would make you think the first third of a normally pulled shot of espresso is predominantly acidic, the last predominantly bitter and the middle balanced between the two. That isn't necessarily the case. I agree taste is subjective, but I tend to think of the first third to be intense, the second less so, but similarly balanced and the last third thin and dull. Slowing a shot down emphasizes the first third, speeding up shifts it towards the last third with (agreed) a tip of the sour / bitter balance.
    Crema_Lad and LeroyC like this.

  21. #21
    Site Sponsor Leaf_Bean_Machine's Avatar
    Join Date
    Jul 2017
    Location
    Perth, WA
    Posts
    9
    Some interesting thoughts on this topic from Matt Perger available at the following links:

    https://baristahustle.com/blogs/bari...ow-to-taste-it

    https://baristahustle.com/blogs/bari...action-tasting
    Crema_Lad and greenman like this.

  22. #22
    Senior Member Crema_Lad's Avatar
    Join Date
    Dec 2008
    Location
    Melbourne, Victoria, Australia, Australia
    Posts
    174
    Interesting articles and tasting experiments above ^^^

    I was just looking at something similar in another thread about the 'salami shot' method https://youtu.be/2aD33p4_fJo
    It shows splitting a single shot into a new cup every 5 seconds of the pour, then tasting each. Is this essentially doing the same or achieving something quite different again regarding taste of the shot?

  23. #23
    Site Sponsor Leaf_Bean_Machine's Avatar
    Join Date
    Jul 2017
    Location
    Perth, WA
    Posts
    9
    Hi Crema_Lad. The experience suggested in Chris' video there is also a great exercise - it's more about tasting which compounds are extracted at different points of the shot, as opposed to tasting the overall extraction %, which is what Matt Perger's dilution test does.

    Both are extremely useful and interesting so worth doing both when you have some quiet time alone with your machine.
    Crema_Lad likes this.

  24. #24
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Quote Originally Posted by Leaf_Bean_Machine View Post
    Some interesting thoughts on this topic from Matt Perger available at the following links:

    https://baristahustle.com/blogs/bari...ow-to-taste-it

    https://baristahustle.com/blogs/bari...action-tasting
    Ah thanks for those links!

    Awesome info in there, but in that first article, again I'm not too sure, but I think once again the terms have been used in the opposite way I talked about earlier... so am confused again haha.

    He's saying underextraction occurs with too slow a flow (ristretto), sour, lacking sweetness etc

    And that over extraction occurs with too long a shot, bitter etc etc

    Whereas we seemed to conclude


    "-fast flowing shot or stopping shot too short (even if it's a slowflowing shot) are both underextracted (BECAUSE in both cases we've achieved less than 18% solubles dissolved)
    =generally too sour, flat

    -slowflowing shot or stopping a shot far too late is overextracted (BECAUSE in both cases we've achieved more than 22% solubles dissolved)
    =generally too harsh, bitter"

    Ah unless he was only really addressing volume of shot (as opposed to flow rate), actually I think that's it... underextr he was more talking about cutting a shot too short (even though he did mention ristretto which would be slower flow, I think THIS is what confused me haha), as opposed to too slow a flow rate (which would then result in overextraction)


    Just piecing it together in my head... think I've got it

    P.S. oh and loved that second article experiment, that would be really cool to do, would have to get my home workflow a bit faster though for 7 espresso to not cool down too much

  25. #25
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote Originally Posted by simonsk8r View Post
    Ah thanks for those links!

    Awesome info in there, but in that first article, again I'm not too sure, but I think once again the terms have been used in the opposite way I talked about earlier... so am confused again haha.

    He's saying underextraction occurs with too slow a flow (ristretto), sour, lacking sweetness etc

    And that over extraction occurs with too long a shot, bitter etc etc

    Whereas we seemed to conclude


    "-fast flowing shot or stopping shot too short (even if it's a slowflowing shot) are both underextracted (BECAUSE in both cases we've achieved less than 18% solubles dissolved)
    =generally too sour, flat

    -slowflowing shot or stopping a shot far too late is overextracted (BECAUSE in both cases we've achieved more than 22% solubles dissolved)
    =generally too harsh, bitter"

    Ah unless he was only really addressing volume of shot (as opposed to flow rate), actually I think that's it... underextr he was more talking about cutting a shot too short (even though he did mention ristretto which would be slower flow, I think THIS is what confused me haha), as opposed to too slow a flow rate (which would then result in overextraction)


    Just piecing it together in my head... think I've got it

    P.S. oh and loved that second article experiment, that would be really cool to do, would have to get my home workflow a bit faster though for 7 espresso to not cool down too much
    That's it Simon, that was the final piece of the puzzle for me too. I just couldn't understand how something could be both under extracted and strong, or vice versa over extracted and weak. What it comes down to is the volume of water that the coffee is exposed to. So flow rate is only part of the equation as you have to factor in time as well to get the whole picture.
    shewey likes this.

  26. #26
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Quote Originally Posted by LeroyC View Post
    That's it Simon, that was the final piece of the puzzle for me too. I just couldn't understand how something could be both under extracted and strong, or vice versa over extracted and weak. What it comes down to is the volume of water that the coffee is exposed to. So flow rate is only part of the equation as you have to factor in time as well to get the whole picture.
    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:

    Quote Originally Posted by LeroyC View Post
    Yes extraction is actually a measurable outcome (with the correct equipment) as it's the amount of dissolvable coffee solids that end up in the cup. It's a result of the level of contact the coffee has had with water while brewing which is determined by time and/or the volume of water used.
    shewey and LeroyC like this.

  27. #27
    Member
    Join Date
    Jul 2014
    Posts
    95
    If you think about it, you can have under- and over-extracted plunger coffee too and there's no flow :-)

  28. #28
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Haha great point

  29. #29
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote Originally Posted by kbilleter View Post
    If you think about it, you can have under- and over-extracted plunger coffee too and there's no flow :-)
    Actually it looks like it's almost impossible to over extract plunger coffee if it's well made. As long as you stop agitating the coffee once all the water is added the grounds eventually all sink to the bottom and stop extracting. You can definitely have under extracted plunger coffee. Over extracted plunger coffee is just badly made plunger coffee.

  30. #30
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Quote Originally Posted by LeroyC View Post
    Actually it looks like it's almost impossible to over extract plunger coffee if it's well made. As long as you stop agitating the coffee once all the water is added the grounds eventually all sink to the bottom and stop extracting. You can definitely have under extracted plunger coffee. Over extracted plunger coffee is just badly made plunger coffee.
    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 )

  31. #31
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote 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.
    Crema_Lad likes this.

  32. #32
    Senior Member level3ninja's Avatar
    Join Date
    Nov 2013
    Location
    Casula, NSW
    Posts
    526
    +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!
    Crema_Lad likes this.

  33. #33
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    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
    Crema_Lad likes this.

  34. #34
    Senior Member Crema_Lad's Avatar
    Join Date
    Dec 2008
    Location
    Melbourne, Victoria, Australia, Australia
    Posts
    174
    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
    simonsk8r likes this.

  35. #35
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    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..
    Crema_Lad likes this.

  36. #36
    Site Sponsor Leaf_Bean_Machine's Avatar
    Join Date
    Jul 2017
    Location
    Perth, WA
    Posts
    9
    Quote 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.
    simonsk8r and level3ninja like this.

  37. #37
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    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...

  38. #38
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote 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.
    simonsk8r likes this.

  39. #39
    Senior Member Barry O'Speedwagon's Avatar
    Join Date
    Dec 2011
    Location
    PRL
    Posts
    2,209
    The analysis at Home Barista in the link below is also very well explained:

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

  40. #40
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    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

  41. #41
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Quote 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

  42. #42
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,331
    Quote 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.

  43. #43
    Senior Member
    Join Date
    Aug 2007
    Location
    Melbourne
    Posts
    155
    Quote 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

  44. #44
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote 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.
    MrJack likes this.

  45. #45
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Quote 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.

  46. #46
    Senior Member
    Join Date
    Aug 2007
    Location
    Melbourne
    Posts
    155
    Quote Originally Posted by LeroyC View Post
    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.
    Yes, agreed, my maths was backwards.

  47. #47
    Senior Member LeroyC's Avatar
    Join Date
    Sep 2013
    Location
    Woodend, New Zealand
    Posts
    1,600
    Is it starting to make sense Simon? I've been sifting through old BH and Jimseven posts to see if there's anything that could help you. The only one that really stuck out was this BH blog post - https://baristahustle.com/blogs/bari...cipes-strength The last section in particular, called "'The Perfect Strength' could be useful.
    Quote 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...

  48. #48
    Member
    Join Date
    Dec 2016
    Location
    Netherlands
    Posts
    77
    Quote 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
    In the classic definition, a double espresso would measure 60 ml volume. Because this includes crema, which has a far lower density than the actual liquid, this would be way less than 60 grams already. Since different coffees produce different amounts of crema, it makes more sense to define a shot by mass rather than volume. 18 grams of ground coffee "should" produce a 36 grams shot, but plenty of people gravitate towards a more concentrated version of espresso.

  49. #49
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,331
    As I understand it, the brewing control chart was created based on experiments with brewed coffee - it's relevance to espresso taste preferences is questionable.
    LeroyC likes this.

  50. #50
    Senior Member simonsk8r's Avatar
    Join Date
    Oct 2009
    Location
    Geelong
    Posts
    494
    Behmor Brazen - $249 - Free Freight
    Ahhh a little bit... have read these posts a few times over and I think I get it maybe haha.. I did understand bits of it, I'll have a look at the article, thanks so much for looking for me I do appreciate it.

    So TDS is a ratio expressed as a percentage of espresso solubles (that which can be dissolved and taken away by the water) divided by the espresso mass itself, to get a percentage of all the dissolved solids within the beverage, ie the percentage in an espresso of the total dissolved solids relative to the total espresso mass extracted (ideally 8-12%?)?

    Whereas extraction percentage is just the percentage of solubles extracted from the grounds (but leaving total espresso mass beverage out of it)....? )(ideally between 18-22%)?

    Thanks everyone for all your help, I'm sure it'll click haha, whether it's something that will help me in espresso extractions or not I'm too not sure unless I had a refractometer... it is fascinating nevertheless!

Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •