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Thread: Espresso minutiae.

  1. #1
    Senior Member Yelta's Avatar
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    Espresso minutiae.

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    With so many debating the minutiae of espresso extraction at the moment I'm wondering how many have read
    The professional barista’s handbook – Scott Rao

    http://www.jimseven.com/2008/02/28/b...ook-scott-rao/

    or are even aware of its existence?

    In it he covers/discusses grinding, dosing,grooming,tamping, water temp as well as almost every other area of producing good espresso.

    After having read it I'm sure you will view the subject in an entirely different light, who knows, for a few the penny may even drop.

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    There's a penny test now? Gonna have to go raid my 2up kip for this. I was worried enough about the nickel a 5 cents is made of on my coffee but now I have to risk copper?

    Didn't know of the book before but will keep an eye out for it. Thanks.

  3. #3
    Senior Member Yelta's Avatar
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    Quote Originally Posted by Journeyman View Post
    There's a penny test now? Gonna have to go raid my 2up kip for this. I was worried enough about the nickel a 5 cents is made of on my coffee but now I have to risk copper?

    Didn't know of the book before but will keep an eye out for it. Thanks.
    They're talking about an American penny JM, similar in size to our 5 cent piece, umm, you don't leave the coin in place during extraction, the measuring process is carried out dry, when all looks ok the result (weight) is noted and the coin removed/

    Just following my link will lead you to the book.

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    Last edited by Steve82; 4th December 2013 at 09:15 PM. Reason: Reason: To much goopypoopy

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    Quote Originally Posted by Yelta View Post
    They're talking about an American penny JM, similar in size to our 5 cent piece, umm, you don't leave the coin in place during extraction, the measuring process is carried out dry, when all looks ok the result (weight) is noted and the coin removed/

    Just following my link will lead you to the book.
    Um... I was talking about your comment, the one that went, "who knows, for a few the penny may even drop" - le sigh...

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    Quote Originally Posted by Yelta View Post
    With so many debating the minutiae of espresso extraction at the moment I'm wondering how many have read
    The professional barista’s handbook – Scott Rao

    Book Review: The professional barista's handbook - Scott Rao « jimseven

    or are even aware of its existence?

    In it he covers/discusses grinding, dosing,grooming,tamping, water temp as well as almost every other area of producing good espresso.

    After having read it I'm sure you will view the subject in an entirely different light, who knows, for a few the penny may even drop.
    I think that it's an excellent book. He's just released an e-book about espresso extraction that is great as well. These books do focus on minutiae... I was uncertain as to whether the OP referencing the book was sarcastic or serious.

  7. #7
    Senior Member Yelta's Avatar
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    Quote Originally Posted by Steve82 View Post
    This is an interesting part that goes against the grain around these parts, funny enough the best tasting shots I have had are from the " single shaped " filter on BES900 and my old levers....WARNING this might be to technical and too many words!

    Basket Shape and Extraction
    A standard single basket is shaped like a truncated cone, while a standard double
    basket is cylindrical, or nearly so. Does basket shape affect extraction quality? The
    answer is a qualified yes.
    Earlier in this chapter it was noted that the upper layers of the coffee bed yield
    more solids than do the lower layers during extraction. Such uneven extraction is
    detrimental to flavor and brew strength: the upper layers overextract, yielding bitterness
    and astringency, and the lower layers underextract, resulting in less sweetness,
    less brew strength, and perhaps some underdeveloped flavors.
    The use of cylindrical baskets exacerbates this uneven extraction, whereas using
    truncated-cone baskets can balance some or all of it. To explain, consider a hypothetical
    set of well-prepared extractions, one in a cylindrical basket, and the other
    in a truncated-cone basket. For the moment let's assume fines do not migrate and
    no significant channels form in either extraction. Imagine you can see inside the
    coffee beds during the extractions. In your mind's eye cut each bed into a series of
    thin horizontal layers, or cross sections. (Visualize the layers as a stack of discs.)
    In a cylindrical double basket the volume of liquid flowing through each layer is
    equal. (Let's ignore the effect of water absorption for the moment.*) Also, the area
    of each layer is identical. Therefore the volume of liquid flow per unit area is the
    same in all layers.
    In a truncated-cone basket the volume of liquid flowing through each layer is
    also equal. However, the upper layers have larger areas, and the liquid encounters
    layers of less and less area as it descends the coffee bed. Therefore, during extraction
    the volume of liquid flow per unit area increases as the liquid descends. (Think
    of it as a road merging from two lanes into one; the same volume of cars flows
    down the road before and after the merge, but the volume per lane doubles after
    the merge.)
    In a single basket, the greater flow per unit area in the lower layers results in
    higher extraction yield from those layers. Therefore, in these hypothetical extractions,
    the shape of the single basket provides a more uniform extraction.
    '* In real life, grounds absorb water. This makes calculating the flow through each layer complicated,
    but it doesn't change the fact that there is greater liquid flow, and hence extraction, per unit area
    in the lower layers of a truncated-cone basket than in the lower layers of a cylindrical basket.
    Steve this thread was intended as a heads up re a book that could be of great assistance to many posting on this forum at the moment, not another bl00dy thread of gobbledygook that few here understand and even fewer care about.

    As a matter of interest when quoting from copyright material it's common courtesy (possibly a legal requirement) to acknowledge the author.
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    Senior Member Yelta's Avatar
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    Quote Originally Posted by kwantfm View Post
    I think that it's an excellent book. He's just released an e-book about espresso extraction that is great as well. These books do focus on minutiae... I was uncertain as to whether the OP referencing the book was sarcastic or serious.
    Evening Kwantfm, my original post was quite serious, its a well written book which as you say does focus on the minutiae, regardless, its can get technical but I'm sure most would gain something from reading it.

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by Journeyman View Post
    Um... I was talking about your comment, the one that went, "who knows, for a few the penny may even drop" - le sigh...
    Oh, that penny bit slow today.

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    Senior Member Journeyman's Avatar
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    Quote Originally Posted by Yelta View Post
    Oh, that penny bit slow today.
    Ah... the penny dropped...

  11. #11
    Senior Member Yelta's Avatar
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    Quote Originally Posted by Journeyman View Post
    Ah... the penny dropped...
    Walked right into that didn't I.

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    Quote Originally Posted by Yelta View Post
    With so many debating the minutiae of espresso extraction at the moment I'm wondering how many have read
    The professional barista’s handbook – Scott Rao

    Book Review: The professional barista's handbook - Scott Rao « jimseven

    or are even aware of its existence?

    In it he covers/discusses grinding, dosing,grooming,tamping, water temp as well as almost every other area of producing good espresso.

    After having read it I'm sure you will view the subject in an entirely different light, who knows, for a few the penny may even drop.
    Hi again Yelta

    Gotta laugh: http://www.scottrao.com/Espresso-Extraction.pdf has his strong recommendation for VST baskets.

    I love the wonderful world of coffee. Viva La Difference.

    BTW, it is a good read and, even better, the man can string together a decent sentence. That alone is worth support in these increasingly illiterate days.

    Enjoy your brew.

    TampIt

  13. #13
    Senior Member Yelta's Avatar
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    Quote Originally Posted by TampIt View Post
    Hi again Yelta

    Gotta laugh: http://www.scottrao.com/Espresso-Extraction.pdf has his strong recommendation for VST baskets.
    TampIt
    Evening Tampit, when I posted the original in this thread I knew someone would pick up on the VST thing.

    Knowing the world of publishing I imagine he was very nicely remunerated for his unembarrassed plug, do you really believe Al Pacino drinks Vittoria coffee? Vittoria Coffee commercial with Al Pacino (1of4) - YouTube

    When the original The professional barista's Handbook was published in 2008 VST were not even on the market and he had very little to say on the subject other than an explanation of differences between single and double baskets.

    Oh, did I mention, I much prefer Precision baskets, quite a bit cheaper, easier to use and produce better coffee with less effort.
    Dimal and TC like this.

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    Quote Originally Posted by Yelta View Post
    Walked right into that didn't I.
    Yep... sure did.

    Found the book online and have been doing some reading and I have a couple of puzzles...
    Quote Originally Posted by Scott Rao - The Professional Barista's Handbook
    ]After dosing and before tamping, a barista should groom the dose. Grooming involves redistributing the upper layers of the coffee bed (or, in the case of the Weiss Distribution Technique, the entire coffee bed), eliminating any extra grounds if the barista deems the dose too large, and then polishing the surface of the coffee bed before tamping.
    Polishing before tamping?

    Also...
    Quote Originally Posted by Scott Rao - The Professional Barista's Handbook
    Contrary to popular belief, the difference in flow resistance caused by lighter and harder tamping is minimal...

    ...Contrary to popular belief, the difference in flow resistance caused by lighter and harder tamping is minimal.9 Once the coffee has been tamped with enough pressure to eliminate any large void spaces in the bed, additional tamping pressure will not have much effect on extraction quality or flow rate....

    ...Very firm tamping does not seem to offer any benefits, but there are at least two reasons to tamp lightly: it causes less stress on the barista's wrist and shoulder, and it makes it easier for the barista to achieve a perfectly level tamp. Keeping the tamper level, squeeze it gently onto the grounds. That's it. There is no need for a twist or a second tamp.
    While this has been my experience (the 2nd of the benefits) as mentioned in My New Machine thread, he does seem to be making the point for lighter than 30kg tamping (he mentioned 50lbs)

    I'm also wondering about part of Steve's quote - that cylindrical filters exacerbate the uneven extraction between the surface and lower areas of the puck. It seems to me, although it is not mentioned, this might be why progressive tamping gives a fuller flavour profile - with pressure more evenly distributed throughout the puck, the extraction might be more consistent through the whole of the depth rather than just part.

    Also his comment about harder tamping might also apply to what TampIt has said in other threads about the 300lb tamp - maybe the reason harder tamping doesn't have much effect is because of the pressure distribution issue? Think of a pile of sand - hit it with a heavy weight and only the top compresses or moves from under the weight - if the pressure applied all the way down as is apparently thought by most people on CS, most of the sand would disappear from under the weight, but that isn't what happens - the sand squashes out sideways leaving a solid 'puck' under the weight.

    In a filter, the sideways movement is constrained, but the same physics of the grains is still happening. i.e. the vertical force is being transferred sideways.

    *grins* Regretting telling me about this book, aren't you?

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    Quote Originally Posted by Yelta View Post
    Evening Tampit, when I posted the original in this thread I knew someone would pick up on the VST thing.

    Knowing the world of publishing I imagine he was very nicely remunerated for his unembarrassed plug, do you really believe Al Pacino drinks Vittoria coffee? Vittoria Coffee commercial with Al Pacino (1of4) - YouTube

    When the original The professional barista's Handbook was published in 2008 VST were not even on the market and he had very little to say on the subject other than an explanation of differences between single and double baskets.

    Oh, did I mention, I much prefer Precision baskets, quite a bit cheaper, easier to use and produce better coffee with less effort.
    Evening Yelta. Hope all is well.

    You have previously mentioned Precision baskets. My only "second hand" knowledge of them is a Sydney coffee fiend who reckoned they were a rough equivalent to Synesso's (a good "old school" tough basket) and then went to VST's. He will never go back. Looking them up online, the photos show nowhere near the flow rate potential of VST's: possibly why they are an easy "drop in and forget" replacement. Different strokes.

    If I can source them in Perth, I may try a single and 15-ish double: otherwise the freight is more than the baskets. At worst, they can join the 50+ collection in my shed (including a few of my old Synessos, my previous fave).

    Your comments on "nicely remunerated for his unembarrassed plug": you may be correct, however it seems to be the only plug in the online sample. They are also the only product I know of other than naked p/f's that rewrite the whole coffee body of knowledge. Ever read Machiavelli's paragraph on the resistance to change? Advantage | There is Nothing More Difficult has the link. Not bad for 1493ish. Still too true.

    Rao: I am interested enough in his approach to see if my local bookshop (think CS fiends / bloodhounds in paperback guise) can get them.

    Have fun.

    TampIt

    PS added after refresh: loaded about 4 hours ago, before the frenetic activity...
    Last edited by TampIt; 5th December 2013 at 12:17 AM. Reason: PS added.

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    Quote Originally Posted by Steve82 View Post
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    Hi Steve82

    I waded through the post via Yelta's comment. FWIW, easy to follow & I suspect he (anon author) is at least partially correct (so does Jim Schulman in a 2011 post on singles).

    What is the reference? I was writing my own two posts earlier and missed all on this thread since post three.

    Cheers

    TampIt

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    It's a quote from the book, page 49. Section is Basket Shape and Extraction.

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    Quote Originally Posted by Journeyman View Post
    It's a quote from the book, page 49. Section is Basket Shape and Extraction.
    Thx. Even more reason to get it.

    TampIt

  19. #19
    Senior Member Yelta's Avatar
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    Quote Originally Posted by Journeyman View Post
    Yep... sure did.
    Morning Journeyman, I have no problem at all with anyone quoting me, as long as the quote is kept in context, the above was plucked from the middle of another exchange and used dishonestly in an attempt to give credence to a subject I had not even mentioned.

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    Ah, I see. I thought your response was a bit prickly to Steve82, but then all I saw was he was quoting from the book. Didn't make sense you'd react that way to something from a book you recommended.

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    Quote Originally Posted by Journeyman View Post
    I'm also wondering about part of Steve's quote - that cylindrical filters exacerbate the uneven extraction between the surface and lower areas of the puck. It seems to me, although it is not mentioned, this might be why progressive tamping gives a fuller flavour profile - with pressure more evenly distributed throughout the puck, the extraction might be more consistent through the whole of the depth rather than just part.
    I actually found the explanation lacking. Espresso extraction is not a steady state process, so flow is just one of many key variables and as a result you can't draw any firm conclusions about why a single could be better than a double from the very very simple model proposed in the quoted extract.
    Important to consider is the rate of mass transfer (i.e. extraction from the puck) will also depend on factors such as concentration in the water and viscosity. Both of which will vary through the puck.

    It doesn't even seem to have been firmly established that the composition of the espresso is different from a single to a double, without which, the whole argument is invalid!
    Whenever you model a system, you should always identify and interrogate your inherent assumptions.


    Espresso extraction is complex to model, but is not mystical or particularly unique. All of the processes involved in espresso are examples of more general, well studied concepts which make up the field of Chemical Engineering.
    Expert baristas trying to explain the mostly subjective or anecdotal observations, based on a limited understanding (or complete lack of awareness of) the fundamentals or heat and mass transfer, fluid mechanics and chemistry, is probably why there is so much dogma and misinformation surrounding coffee in the first place. Such explanations would thus merely be hypotheses which deserve further exploration.


    Of couse, even if they can't explain 'why' convincingly, I'm sure the expert baristii can demonstrate HOW to make a nice coffee.
    Last edited by MrJack; 5th December 2013 at 12:17 PM.

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    Senior Member mwcalder05's Avatar
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    When I make coffee, I can honestly say that I don't really think too much about the chemistry. I think about what tastes good and what my taste buds like. To me, that's what coffee is about. Not all this fancy talk, just make the coffee and if it tastes good, fantastic! If it doesn't, change one variable at a time.

    Michael

    PS: Although, tbh, I do get a little interested in all the chemistry stuff when the refractometer comes out :P But this isn't during a rush, this is just some spare time fiddling. When I'm on shift, I trust my tongue.

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    I'm on board with trusting the senses. I ignore Use-By dates - I trust my nose implicitly. It's good enough to get suss about an oyster in the split second as it approaches my mouth and I've never had salmonella or other food poisoning because I won't eat anything that smells 'off' to me.

    And I have eaten some very strange things over the years...

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    Quote Originally Posted by Yelta View Post
    Morning Journeyman, I have no problem at all with anyone quoting me, as long as the quote is kept in context, the above was plucked from the middle of another exchange and used dishonestly in an attempt to give credence to a subject I had not even mentioned.
    Hi Yelta,

    I fully agree via the Steve82.

    I trust you saw my VST post as a gentle dig, not an attempt to discredit or attack (it absolutely wasn't). Just my warped sense of humour coming out to play.

    Be a really boring world if we all agreed on everything all the time.

    Enjoy your brew.

    TampIt

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    Thought this might be better suited to this thread than the one-way valve thread. Just a few thoughts on discussing the "unimportant" details vs espousing expert opinion, when responding to enquiries from people who's experience is contradictory to ones own...

    From the hypothetical perspective of someone asking a question (to a hypothetical 'expert'):
    If your observations and experiences (as the 'expert') appear to be at odds with my own, and you offer nothing in explanation except "I know 'x' because I have seen it, and my experience is more extensive than yours", then why should I believe you?

    If, on the contrary, you were to offer possible explanations for the differences in observations, then I might come to accept your observations as an extension of my own, as opposed to an enforced substitution. Knowledge and wisdom are more than just 'facts'.

    Of course, that would be more a difficult and involved response, and require more of your time than you think justified.

    Alternatively, if you don't have the insights yourself, it would be nothing but a case of the blind leading the blind anyway (which only perpetuates misinformation). In which case politely indicating that you can't offer an explanation as to why your experience differs to mine (which incidentally Greg Pullman did this morning), might be more effective.

    I consider it one of the strengths (and weaknesses) of forums that there is such a variety of different backgrounds and perspectives; there always seems to be something new to learn from someone, or someone to ask the silly question I won't or hadn't thought of.

    Maybe there would be some merit in s "minutae" forum section, where people might ask the apparently unpopular questions, and where those who need to know the 'how and why' in addition to the 'what, where and when', can attempt to find it?
    ASchecter likes this.

  26. #26
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    I really dont give too much thought to the individual variables on a day to day basis - but I do think its important to understand the mechanisms at play when extracting a coffee, and to be able to adjust on the fly if necessary

    I use VST baskets and laser cut shower screens at work, and to me at least there's a discernable difference in shot quality. My only qualm if you would call it that is that the baskets need to be rinsed more frequently, as they tend to become clogged with oils, but the shower screen is effectively self-cleaning and lower maintenance, as the uniform holes are so small that coffee solids cant travel back up and block the screen, so they require less frequent maintenance, and are IMHO at least, more reliable when there's more than one person working the machine

    Constant monitoring of flow rates and crema volume are a given in my book, as is the ability to rapidly identify any potential deterioration in shot quality, and to be able to fix it quickly and easily

    And Im afraid Im going to have to disagree about tamp pressure, as I get much better and more consistent results using an hydraulic tamper, which works better for me in maintaining a firm to hard tamp consistently, and I make sure that I always use the hydraulic tamper for doubles, espresso, and long blacks, as I consistently get better results than would otherwise be the case!

    My five cents worth!

    ACg
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  27. #27
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    Quote Originally Posted by Yelta View Post
    when I posted the original in this thread I knew someone would pick up on the VST thing.Knowing the world of publishing I imagine he was very nicely remunerated for his unembarrassed plug
    You can imagine all you want, but you are wrong. Scott was not and is not "remunerated" for praising VST baskets. If you read what he's written about them you'll find he goes into detail why (in his opinion) VSTs are superior to the others: more consistent from basket to basket, better in taste balance, more efficient when the extractions are objectively measured.

    Quote Originally Posted by Yelta View Post
    Oh, did I mention, I much prefer Precision baskets, quite a bit cheaper, easier to use and produce better coffee with less effort.
    Since you repeatedly go out of your way to mention that you prefer the Precisions to VSTs, it would be easy to "imagine" that you are "very nicely remunerated" for doing so. But I have not said that and would not say that, because I have absolutely no evidence that it is so.

    IMHO, NOT casually slandering someone is simply (to use your expression) "common courtesy."
    mwcalder05 and Dragunov21 like this.

  28. #28
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    Quote Originally Posted by Journeyman View Post
    I'm also wondering about part of Steve's quote - that cylindrical filters exacerbate the uneven extraction between the surface and lower areas of the puck.
    Scott and I had an email conversation about that very subject a couple months ago. We both agreed that it's an interesting theory, but it hasn't been thoroughly tested.

    I pointed out that various "truncated cone" designs have in my experience yielded inferior results (either poor taste balance or low extraction yields or both). Scott countered that I hadn't tested filters that taper steeply enough for a fair test of his concept. But he also conceded (in good humor) that it was simply a theory, without (so far) any supporting evidence.

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    Quote Originally Posted by askthecoffeeguy View Post
    I use VST baskets and laser cut shower screens at work, and to me at least there's a discernable difference in shot quality.
    Are laser cut shower screens available for E61? Where can I buy them?

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    Behmor Brazen - $249 - Free Freight
    I got mine from Talk Coffee
    Shower screen IMS competition



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