UNDERSTANDING ESPRESSO EXTRACTION: Ultimate Guide on Pressure, Flow and Resistance

[@eduardofcgo]

We really need more of this type of video. KZbin is already filled with workflow videos and gear reviews. I am a proud patreon supporter, thanks Lance!

[@charliehampton7076]

Lance Hedrick is the real MVP! I've read a lot of coffee books, but I've never seen so much amazing information on coffee extraction. This kind of knowledge is almost priceless and we should be very grateful that is completely free and so easily understandable as well as in a nice video so such at this one.

[@Proton-m4y]

Man… thank god for this guy and his incredible amount of passion and enthusiasm. I’m new to making espresso. I started researching and found just how incredibly scientific the entire process is. I was hooked immediately. I am waiting for my new ECM Synchronika to come in, and his videos have given me more information than any other source out there so far. It’s only given me more excitement to experiment myself. I’m the type of person that loves to progress in how well I do everything in life. It seems with espresso, it’s almost endless in how far you can go in terms of perfecting your process. Having a guy like Lance that’s extremely passionate, not to mention very intelligent (he uses all the resources at his disposal to explain his theories/data), is what industries in today’s world need to continue to grow. The coffee industry owes him a great deal. Thanks Lance!

[@MuggsFJ]

This guy is bang on. People laugh when I tell them, but espresso extraction is a materials engineering problem through and through.

[@HauntedSheppard]

Hi Lance, I don't know about others, but I would really like some more in depth video's on the processing types (maybe the perfect oppertunity to invite people on). I know I can read it in cientific papers and stuff but I'm already seeing my fair share of those, and nothing beats a passionate person telling a story.

[@JonathanChen-kb5fr]

kzbin.info/www/bejne/imqpZKttnbpohZosi=i6sJBq-4V_UyOkb7

[@loganmontgomery1955]

I second this

[@julianpark93]

Coffee processing? I might check out Leaderboard’s playlist for that!😊

[@BrightMindsHub-h3j]

Three main processes. Seen them all on the farm in Colombia. If that’s what you are talking about.

[@zsvrljuga1]

This is most clear video on pressure, flow and profiles ever!

[@JLeverEspresso]

Greg from JLeverEspresso here, Awesome video Lance, I so appreciate all the youtubers breaking down and sharing all their extensive knowledge on espresso with the public so they can make better coffee, half of all I know on espresso theory, I Iearned on youtube :) Keep it up! I think your subscriber count should be way way higher, for the amount of effort you put into it.

[@asok15146]

Wow, a 25-minute video, but so deep and dense with new info that I could have watched it for two hours with much more detail. I truly appreciate that you experiment and measure everything instead of just repeating all the common "knowledge". Science FTW! :)

[@ThingsIdRatherBeDoing]

Dude this was great. Keep this kind of science and discussion of data in more videos. I have a good feel for what's happening and how it relates to practical technique.

[@howienordstrom1290]

You just verified something that I discovered by mistake. I'd been doing low pressure bloom to high pressure extractions but was never fully satisfied. Last week, while being a bit mindless, I mistakenly brewed an espresso with high pressure to low pressure. Bam! Much sweeter, full and balanced. Repeating the process has consistently provided a more pleasantly extracted espresso. 👍

[@Mustapha_El_Hamdaoui]

Could you please share your pressure/flow profile? at what point during the shot you start to decrease the flow and at what point you stop your shots?

[@BurnsRubber]

My shots are 1000% better! Thanks Lance! Just applied the knowledge in this video on my ECM E61 machine with flow control this morning. Starting the pull at full flow, then closing flow to bloom for around 10s then opening to near 9 bar and tapering flow down at the end. Extraction is hugely improved. Shots have great balance and complexity. Like candy! BTW: I find grind speed a great tool to control puck resistance. I am pulling 21g baskets at min RPM on a Lagom P64. The slower speed reduces fines overcome by the larger basket. Shots have clarity and body and this technique works well. Edit: Yes extraction is higher - wow the caffeine is hitting me right now after two 21g basket.

[@Mustapha_El_Hamdaoui]

How long you kept the full flow before closing it for the 10 s bloom?

[@BurnsRubber]

@@Mustapha_El_Hamdaoui Typically 20s but I throttle down based on pressure drop and flow change.

[@Mustapha_El_Hamdaoui]

@@BurnsRubber Thanks for the prompt reply! I will definitely try that :)

[@coffeenerdaaron]

Another killer video man! You always go so deep into these topics and truly educate the coffee community. Can't wait for the next one!

[@dopplegangdave]

I literally just unboxed my Bianca V3 yesterday. This has really helped me conceptualize how to play with the machine and think about my results. Cheers!

[@maxierose564]

Beautiful machine, beautiful cups, beautiful espresso! Love the coffee nerdiness.

[@LanceHedrick]

thank you! Hope you find it helpful!

[@maxierose564]

@@LanceHedrick It was very helpful! An awesome video. :)

[@kashyapakshay]

Lance, this video was amazing. As a biochemist by study and pour over veteran who just got his first espresso machine, your explanation between technical details and takeaways was exactly what I was looking for. Great editing and lighting too.

[@colemangolf1]

Yes -Yes!... that’s how it’s done. Solid education, well presented and looking forward to hearing more from Lance. 👏👏👏👏

[@patrickpourreau4234]

Hey Lance, I love these kinds of videos! Dude, you’re so good at interpreting data and explaining it in a way that makes sense. It may be that my engineer brain is the only one that thinks this way, but when you’re talking about dead space and connection between the pump and the puck, I feel like something that could help people visualize that is the idea that air is a compressible fluid and water is incompressible. So air will absorb some of the force exerted by the pump like a spring until it’s displaced with water.

[@LanceHedrick]

Of course. It is a massive talking Point in lever espresso. But not as much in pump machines.

[@JesusRodriguezCisneros]

Love this explanation - very in-depth but now flow makes more sense to me. The way you explained how to save shots based on grind it’s what makes flow a so distinct process that for beginners greatly improves brewing experience. Thanks, Lance.

[@notDYLANCOWLEY]

Fantastic video. This has me rethinking about how I start my Flair shots, and why some of my 'preinfused' shots were not tasting great while some were - I had an inconsistent input flow, I wasn't understanding puck saturation and how pressure relates to it. This is so helpful, thanks for making this.

[@jerrykorten664]

Finally I find somebody talking sense about this stuff. You need to talk to folks at these machine vendors who flow profile thru an empty portafiler and then apply that data to pulling a shot. Total nonsense. I had given up on my P700 adjustable flow valve and am just pulling simple shots now. Maybe I try the variable flow valve again using your guidance. Well done! Thank you.

[@formlessuk]

Such a thought provoking and inspiring video. As an original 2002 Gaggia classic owner who recently fitted pid, pressure gauge and dimmer mods I would be really intrigued to see a video with this knowledge applied to show me manual flow profiles to improve the espresso I have been making. Now off to change my opv back down to read 10 bar on the additional portafilter mounted pressure gauge I have. Before watching your video I thought I was being clever by having it set to around 12 bar and then I would adjust the flow rate to achieve the pressure I wanted eg 2bar for what I thought was good pre infusion.

[@adrianplaysslots]

Lance, you’re the GOAT. Thank you for these videos. This video made me realize 3 things: my Bianca V2 was still flowing a couple G’s per second with the lever off; I always have tiger striping cause my grind is probably too fine; and I don’t need to be hitting 9 bar every time. This is gonna be a fun weekend filled with caffeine with the experimenting that’s about to take place.

[@ecsekiandras]

For me, this is the single most important video about the espresso

[@DanzilF]

This is somewhat overwhelming for me, but appreciate Lance's explaining in simple terms. The more I learn the more I find out I don't know enough :D Can't wait for more. Well done and thanks for this content. Lance deserves the 1M subs :)

[@AnimeKazuki]

Oh wow, TIL that particle distribution of grinder can have a huge effect on your espresso profile. I was always struggling with my Flair because the pressure couldn't maintain a straight 6/9 bars without flow rate getting very fast and messy. Thanks! Now experiment a little now that I understand it a little better.

[@LanceHedrick]

absolutely! Not a bad thing at all. could just be a pairing of a light roast (low puck integrity) and low fines

[@yousuckmorethanido]

@@LanceHedrick what is the solution for this? I have the same exact problem. grind finer and slowly decrease pressure to maintain flow? awesome video btw.

[@kerrycoyle8930]

Thanks Lance... not sure how much others enjoyed this video but I sure did. I believe I probably learned more from this single video then I have from multiple others. Please know that your time and efforts are appreciated. 🙂

[@pieterdendekker8018]

I Love this! As a water engineer I should've done my masters thesis on this subject ;) Instead I went for intermittent water supply in Africa - also had to do with pressure and flow profiles and how they change over time through consumption.

[@multioptipupiloptomy]

Many thanks for this great vid Lance! This year so far - this is the best vid I've seen :) (and as others mentioned already - I needed to watch it twice in order to be able to digest the information) excellent stuff.

[@jhwk1970]

Our Profitec 600 has Flo Control and it never really made sense how I should use it. Now I get it. The improvement in my coffee was absolutely startling. I explained it to my wife and she too was shocked how much better her coffee was. Anyway…….THANK YOU!

[@ycgycgycg]

Equipment reviews are good but these are the type of videos I am looking forward to

[@LanceHedrick]

good! I love making them, to be honest.

[@phildando5640]

Makes me glad I have a Flair58 and a pressensor 🎉🎉 With the flair I’ve never really thought about the significance (until now) of there literally being zero water gap between ‘pump’ and coffee puck as you’re filling the chamber directly above it. So once you pull on that lever you’re having an almost immediate impact.

[@Dotes111]

I have never thought about that either! I do wonder if low-flow "pre-infusion" on the Flair 58 has a different effect than what is described here on the Bianca (as in, you nearly immediately build up pressure when you pull the lever).

[@eda7875]

The flair has something no other machine has. And it is that you can literally feel the shot as you pull. It is a very simple yet very clever machine. You can feel the puck integrity as you pull the shot. I always wondered why the shots out of my flair pro tasted so good compared to when I pull from my modded Gaggia.

[@mescellaneous]

for some reason, i prefer an inclining pressure shot. i think it has to do with countering/challenging the idea that flow is responsible for pulling the solubles out? i am thinking perhaps drag is what im trying to get at as the reason for extraction, not flow. so drag is inevitably higher as there is more solubles diluting into the water, but as the shot goes on, there will be less drag. so an increasing flow rate with a relatively low starting flow rate is the profile i go for when focusing on drag. i looked a little more into this and searched for "highest amount of drag" and interestingly a stackexchange answer said a semi circle with the flat side facing the wind. and that looks similar to tapered baskets. of course there is a lot more to it, i am not sure how resistance and drag can relate if at all. but flow doesnt say much. you can have low flow but extract less per volume. because the drag is also low. and to reduce drag on the edge of the puck for edge extraction, maybe we can look at golf balls, and provide dimpled walls. some more reasons why we might want the "right amount" of flow is that when the flow is too high, it becomes turbulent, which causes unevenness. so an ugly shot is likely not just an aesthetic issue anymore. however, flow seems to correlate somewhat to increased drag forces, so my idea is that we do want to increase flow somewhat, but to the point that it still maintains a laminar flow and not a turbulent one. so starting at a lower flow rate (with finer grind) but eventually increasing it will yield a much tighter ratio, while maximizing drag forces. the finer grind will increase the viscosity or density, in whichever formula you want to use, drag coefficient or stokes law. whereas this idea of maintaining flow at a constant rate seems to be out of the idea of keeping that laminar flow, not taking into account drag forces and extracting solubles. ie if you use too fine a grind, flow will be all messed up and somewhere it will be turbulent as well depending on your machine/pump, causing uneven extraction and all that. and so you might associate the inconsistent flow towards the extraction, when it really is about it being turbulent.

[@Litwinel]

SO INFORMATIVE and can already explain some results with my blooming shots I didn't understand.

[@0whitestone]

Thanks for the awesome video. Your content is always amazing and educational, you're a very good communicator. Before watching, I thought "I know all this, I've seen all of Lance's videos already," but still learned a lot! I just got my first espresso machine, a Flair Neo Flex, and I can use this to experiment and try different profiles with more knowledge going into it. I've been doing 12sec bloom with declining pressure and getting good results, but this definitely helps with more insight into what is happening. Obviously I can't pull as long of shots, and it doesn't have flow rate in the same was as a pump machine, but I can still use this information to help my shots. Thanks for all that you do, you're got to be so busy!

[@omni96]

This is the kind of knowledge I look for when I buy coffee books, but for the first time I'm starting to understand. Just threw away most of my knowledge...this is gold.

[@SKG-d2t]

Best explanation of the saturation rate advantage of a lever machine. I may not go there, but I appreciate it.

[@FreeYourMind12345]

Super helpful and interesting! Based on your advice, I've started using full flow to fill the head space early in the shot, then ramping down with the paddle as needed, depending on the profile. Also, digging the funky music, keep it up!

[@BobertRads]

I don't even drink espresso, but I love watching your espresso videos lol

[@LanceHedrick]

hahaha! Thank you! Hopefully you can apply some of this to your understanding of flow in filter!

[@BobertRads]

@@LanceHedrick absolutely! went from drinking coffee as a necessary evil to get through my day, to looking forward to it every morning thanks to creators like you! So thanks for helping me enjoy coffee :)

[@LanceHedrick]

I love reading that! Thanks for sharing!

[@anthonyzouki]

Hi, i absolutely loved this video, please i want more on this! Thanks lance!

[@rossbrown6649]

I found this video to be a great addition to my (limited) experience using a pressure gauge on an e61 group head. I also have a pump speed controller on my Gaggia Classic Pro, but no realtime pressure info. The best I can do with that is measure the 0 resistance flow rate at the variable pressures the pump produces, and extrapolate from there. But seeing the actual shot pressure is a real aid in dialing in a shot and understanding the shot dynamics. I have reached my endgame equipment setup, so this deep dive into shot dynamics is much more interesting than endless equipment reviews.

[@fabilemusic9992]

Super helpful! These are the videos I am looking for and are so rare to find. Thank you!

[@LanceHedrick]

fantastic! hope you enjoy it!

[@Athrix94]

Lance. Thank you, this was awesome. More of this louder please 🙏

[@xyzzy12345]

I think i spent so much time zoning out thinking about the new things i learned during this video, that i missed a bunch of other things that i could have learned. The knowledge is thick and dense and this one. Syrupy, even.

[@timothysweet6791]

Great video regards to the importance of impact re pressure profiling. With out getting into the nitty gritty of picking apart some of the details. There also were a lot of points I did agree with as well but I’m confident still the argument still stands for controlling pressure monitoring flow and the better consistency of volumetric machinery with digital pressure profiling over that of manual flow control with the combination of human error and flow being a secondary guide to achieving pressure, one that is far less predictable n much more reactive n dependent on the typical variable. I very much enjoyed this video n I have heard the counter claim in full thanks to the quality n detail you go into in this video however. Great production quality n great discussion 😊 still in my opinion one of the best content creators on you tube 👏👏👏

[@LanceHedrick]

You're arguing from a place of a Cafe and consistency. The more control and at a fraction of the cost is manual flow control, which is definitely more cost effective and practical for the majority. Without even getting into which is superior.

[@timothysweet6791]

@@LanceHedrick no in general , yes flow is more cost effective ✅ but definitely not more accurate or consistent. That’s not to say it isn’t effective as in it causes a change that’s 100% true but in terms the ability to control n replicate. I think at this stage it’s ok to disagree I have tested both principle methods so many times over it’s not even funny at this point but yeah there would need to be a way that a human could not only pre predict the tiny variables and perform the exactly appropriate physical action required also in combination with the volumetric stage of that extraction. It’s just not realistic, but I will say this I genuinely enjoy your videos n the respect you offer to engineers of lever machines the feeling is mutual infact I’m willing to hedge my bets there’s probably over a 100 things in this video we probably agree on in contrast to the things we disagree on. I’m open minded I’d just need to see the evidence of a manual flow control trying to compete at the same level of consistency as a digital volumetric pressure profile machine.

[@justinbouchard]

awesome video. it's hard to describe how to attain the "magic" that experience combined with intuition and observation create. you're awesome.

[@chuckburtchify]

This is my favorite video of yours! Great job! I measured an average water debit of 13.2 grams on my ECM Technika IV. I just ordered a flow control kit for it, so will see how things work out with that. Really looking forward to trying out some of the methods you used.

[@bluejumpsweater]

Great video! Please more of these technical vids! 😊

[@LanceHedrick]

I love making these! Just hard to think of topics to be exhaustive on that are conceptual like this haha

[@quaxie]

love this. I have my popcorn ready.

[@TheSimonSDJ]

That transition to the sponsor had me laugh out loud! Also great video Lance! Keep it up☕

[@richardosborne8570]

Oh man I've been doing it all wrong again. I've been saturating at low flow with my dimmer modded machine with a ramp up to max after first drip followed by a slow tail off in flow till reached 3:1 ratio. Will try full flow saturation tomorrow with some Guatemalan. Thank you Lance for the excellent content once again. 👍 From France

[@jdrobison1967]

Same. Like you, I do let the puck fully saturate at low flow before full flow but now curious about reversing the process - full flow then back off at first drip. How did it go for you?

[@richardosborne8570]

@@jdrobison1967 hello. Quite interesting results - had to grind coarser to avoid choking but works really well. Seems to reduce astringency . Needs more experimentation but I wonder about reducing the ratio a little. As always Lance makes you rethink your coffee routine!

[@John-ku7mj]

Nice! I will take some exception to the equation. Quite simply, flow is a result of pressure applied over a resistance. Think of pressure like power, and resistance as weight. If I’m more powerful, I can lift more weight. The beautiful thing about espresso pucks is that the resistance across the puck is a function of the puck history - now think pressure profile. As we know, if we apply max pressure at the group head right away, the puck compresses and offers more resistance. So later on in the shot, the flow would LOWER than if we applied low pressure at the beginning of the shot. Crazy! That’s so many people love flow profiling, but it’s really pressure profiling. 😎

[@tunblimbli]

Got my lelit Elizabeth two weeks ago and you just helped me understand many details. Going for my 6th shot of the day. you know, for science 😂😂. Thanks for all the information.

[@LanceHedrick]

Always for science! Don't let anyone tell you otherwise hahsha

[@AlanArmzzz]

Greatest segue of all time! ⬛️

[@marckirschbaum]

Chapeau Lance! Great video and excellent explanation. In one of your reactions to the video you are saying that Slayer shots are not ideal. I think there are people outside who agree and disagree with this statement. I think it would help to visualise water flow during the different phases of espresso extraction. From these observations, more conclusions can be drawn. There are tracers available which enable this kind of experimental setup and I have used some of them as molecular biology scientist

[@gro967]

The poor scale 😂 Great video as always Lance!

[@hodexter]

Thanks for the video Lance! Would like to see a discussion over changing pump pressure too! I do use a LB too and pull at 6.5 bar pump pressure.

[@PhillipLangenkamp]

As a chemical engineer, I absolutely love all this talk of pressure, follow, and resistance! And it's going to help make even more delicious espresso?!?! 😊

[@petarrusev1259]

Dear Lance, after 9 years of reading different articles, your video opened my eyes about the relation between flowrate and pressure!And not only that, but also about the way to strive about homogenious extraction! Thank you very much! Please, share which is yoru application measuring flowrate and pressure and if it is compatible with Acaia Lunar 2021? Thank you!

[@molina.unofficial]

Hey Lance, great content. Had to watch it twice and brew multiple shots so I was able to understand it correctly but got great results now. I noticed your Bianca is set to 90 degrees. Isn't that super low considering the offset and the temperature that you'll lose at the group head? Or did you change the advanced settings of your machine so that the offset is applied to the boiler in the background? If so, do you mind sharing your settings?

[@wild-radio7373]

No script, no bullshit, love it 👍

[@SecurityDivision]

Perfect 9 bar education pressure to my brains for best information extraction :)

[@caffeineicide]

Very interesting points here - I think what newer baristas should keep in mind that a lot of what’s in this video is specific to needle-valve machines. I work on a San Remo Cafe Racer everyday and it has pre-infusion time setting but no post so it was interesting to see your machine style of espresso.

[@LanceHedrick]

True but the lessons can be applied when dialing in on even flat 9s!

[@porsche911GT3RS40]

Insane video, great work!

[@kieranda3718]

This is brilliant, Lance. I was really excited to see some measurements that explain lots of things I've experienced with manual pressure control on the Cafelat Robot - particularly that shots are much better when you reach high pressure first, before backing off for preinfusion (etc.). I hadn't thought about puck saturation (I assumed this was more to do with the speed and evenness of piston engagement), but it's obvious now that's what's going on!

[@Dan155]

Thanks for thos lovely and informative video. I hope to see a follow up recipe video of the different pressiure profiles/recipes and which coffeea yoid ise each recipe best on❤

[@arbousiersles7381]

packed with great info... thanks for sharing!

[@rafaelrocha8046]

Now that I've finished watching the video, it's time to watch it again.

[@gosman949]

I fell asleep. I will need watch it if I ever get a flow control. Otherwise it is zzzzzzzzzzzz

[@bysk2u]

Thank you!!!! this is so valuable!

[@bentan3579]

Finally someone clearly explained the relationship between flow and pressure in espresso…

[@OhDearBabajan]

I saw a video on your Instagram where you were at an expo or something and you did a bunch of flow profiling tests and talked about flow and pressure. I was waiting for a more formal video like this one. Would’ve been nice if you used the BDB to do it (since I just bought one lol), but I think these concepts and applications are universally applicable so long as your machine as flow profiling capability. Thank you as always.

[@bohsonca]

Are you doing the Slayer mod? I just bought one as well, to replace my Flair 58 which gets really old really quickly if you have to do more than one shot at a time. I'm planning to do the Slayer mod and I'm wondering if closing the needle valve will actuate the OPV as I like my blooming shots. I assume it won't.

[@LanceHedrick]

the slayer mod will do nothing to the OPV, but that doesn't matter. If the puck has degraded, it won't go up to the 9 bar. it will peak elsewhere, unless you go super fine. The OPV acts liike a ceiling. you don't need to hit the ceiling.

[@OhDearBabajan]

@@LanceHedrick I want to also slayer mod my BDB. I find 6-7 bar shots with preinfusion are what I tend to like the most. A few of my favorite coffee shops use a lower baseline pressure with several seconds of lower pressure preinfusion. I want to be able to do this at home but Slayer mod is the only way right? Running the entire shot in preinfusion won’t give me several seconds of 3 bar followed by the rest of the shot in way 7 bar? I’m only asking as I seek more of an automated workflow outside of R and D

[@LanceHedrick]

you can change the OPV of the machine if you want a top pressure of 6-7 bar. not hard. on my first BDB video, I have a "bible" of sorts with all the mods detailed on forums. I would first do that and then use the built in pre infusion option to control the pressure of preinfusion. Shuold be able to get this style of shot with out modding it at all- just changing OPV

[@OhDearBabajan]

@@LanceHedrick thank you Lance! I think slayer mod will be fun especially for lighter roasts…or just to leverage manual control over flow to have fun with a shot regardless of roast

[@rolandkovacs7339]

Really interesting what you say about pre-infusion. I found to get the best result on my Sage Dual Boiler by going manual pre-infusion until around 4-5 grams and then allowing full flow for a 1-2, 1-2.5 ratio with lightly roasted Ethiopian beans. I get very close to the result how my favorite cafe shop makes the espresso from the same beans and I'm very happy with it.

[@LanceHedrick]

That's great! And I didn't say anything a out preinfusion being less than ideal but low flow bring less than ideal. You can have preinfusion coming with a decent flow rate. There is no such thing as a static PI. They differ machine to machine. Your machine could have a fast PI with low pressure

[@ElFlipo1337]

Will compare a turbo shot to a 35 second shot with my bluetooth scale. Really instrested in what makes a turbo sweeter. @@LanceHedrick

[@Ab-ye8wp]

Uncle Lance hit another banger 😊

[@LanceHedrick]

stoked you enjoyed it!

[@coffeewitharthur426]

Lance. This has been my favorite video of yours for a long time. It’s on par with the espresso basics video series you made when I started my journey. I recently got a decent and until then didn’t think much in terms of flow rate. This video really opened my eyes to the world of pump machines and how they work And also showed me why lever machines are the best 😂

[@WD-sr8qz]

Great video!

[@jolonf]

Hi Lance, what are your thoughts on pressurized baskets to control flow? If most 9 bar pump machines are going to push out 9 bars to the end after the puck has lost a bit of resistance, would it be better to have some sort of additional resistance through a pressurized basket (or paper filters)? It seems pressurized baskets are generally a bad thing would be interested in this context why that is.

[@aussieguiri8502]

Hi Lance, have you looked at the literature around hydrogeology? The coffee puck is essentially analogous to a compressed sediment or gravel fill. I would recommend looking at Darcys Law (Q=kAh) as the simplest analogy for the transfer across the puck assuming a 9 bar pressure differential across the thickness.

[@LanceHedrick]

Yes I have and I know Darcy's Law. My friend is a physicist and wrote a book on espresso extraction from that POV. I consistently check in on modern theory with him and a chemist who focuses on coffee.

[@aussieguiri8502]

@@LanceHedrick can you pass on the name of the book please?

[@LanceHedrick]

He hasn't released his book on espresso yet. I'm just privy to advanced copies. He does have one on filter coffee where he discusses darcys law in depth. That book is called the physics of filter coffee

[@AleX-je2sw]

Oh damn, Jonathan is releasing a book on espresso as well? That's good to know

[@intervallum]

If you wrote a book (even though I am sure this info is in someone's book) I would buy it. I definitely think you could create something that people could follow in book form with the knowledge you have.

[@TH-tl8hy]

Thank you Lance for this insightful and assumption-challenging talk! Constructive criticism for the editing: please add in a tiny audio crossfade between cuts to avoid the slight popping that happens when you edit out breaths or silence between sentences. It will give an extra coat of professionalism to the production!

[@brentroman]

Very clever transition into your ad sponsor. For a sec I thought I was gonna learn about some new SCA golden ratio square for espresso! Hahaha

[@LanceHedrick]

hahaha I always try to make them somewhat entertaining

[@brentroman]

👏

[@cheekster777]

Thanks, Lance.

[@LanceHedrick]

absolutely, friend!

[@cheekster777]

@@LanceHedrick 👊🏻

[@db7069]

Very well done, thank you.

[@flipy_]

TY Prof Hedrick

[@cedricrochat6920]

Hi Lance. Did you ever try manipulating flow/pressure after the puck and see how it affects extraction, with a valve installed below the portafilter, like you have on a portafilter equipped with thermometer or manometer. If the resistance could come from after the puck, the ground could be left totally loose, fully soaking in water, like in a French press, but still get extracted under pressure to dissolve gases and get a nice crema when they get back to micro bubble gaseous state under atmospheric pressure. This could maybe get us closer to an even extraction, while keeping the crema. I imagine a shot in which you mix the desired ratio of water and coffee, extract under sufficient pressure to dissolve gases, then release the brewed coffee through the filter. Maybe this is feasible with 5-9g of coffee in much larger basket.

[@loganmontgomery1955]

What an interesting idea

[@pablosanmartinvarela1773]

I watch Lance at 1.5 speed. It's better than drinking coffee.

[@markedis5902]

Lance, please could you do a video on ‘upgrading from your breville/sage grinder that came with your dual boiler to get the best from the dual boiler’

[@Powerwashincrocs]

Very good and nerdy video, love it. Does anyone know what cup that is at the 11:19 mark? It’s beautiful

[@ondrejmitas3325]

I love this video so much. I thought that my pavonis initial burst of water was bad; the crumbly puck demonstrated otherwise. Thank you so much. Can we have a similar video that continues with light(er) roasts but shorter ratios (1:2.5 or so)?

[@tuliominto]

Fantastic video, Lance. Congratulations! When the Gaggiuino video will come?

[@jensencastro6989]

👏👏👏 Christmas came early for people using manual and flow profiling machines 😬

[@StefanLatt-z6v]

Hey Lance, thanks a lot for constantly shedding light on these super interesting yet quite complex topics around espresso! Your videos are helping me out a lot & I really appreciate the effort you're putting into them. You definitely motivated me to start playing with the flow control on my Bianca first thing tomorrow morning (which I haven't touched in a while, since I first wanted to make sure that my puck prep is on point with the new grinder I got 😬) Speaking of the Bianca - am I correct in assuming that you wouldn't recommend using the Bianca's 'Low Flow' Mode without saturating the puck via pre-infusion first? And since you're so adamant about the quick puck saturation - would you recommend to start the Allongé shot with full flow for quicker puck saturation & dial it down to the ~4ml/s once the first drops are hitting the cup?

[@JusBThankful]

Thanks Lance. Looking forward to this one

[@LanceHedrick]

love that! love it when people are excited about video drops

[@rngreenejr]

Can't wait to see your review of the Unica Pro!

[@danielryan4488]

Lance, you are always super awesome about answering questions and I appreciate it. I have a bianca V3 and after watching this... I think you said low flow start isn't good, do you recommend a short preinfusion? I would love to know what is optimal. Thanks

[@mikloscsanady3955]

Profiling Masterclass ❤

[@LanceHedrick]

hope you enjoyed, friend!

[@JakubTarnawski]

Thank you for the video! So, to be clear, are you saying that the electronic low flow function on the Bianca V3 should not be used (as it goes full flow for only the first 3 seconds, which is not yet enough to build pressure, at least if I don't fill the basket to the max)?

[@adammacfarland6415]

Is this going to be a series? I thought this was a great introduction to mechanics, but I think the next step would be to discuss the impact of flow on the taste. If that is even possible to explain…😊

[@paukanadell]

Nice video, quality info as always Lance! A question about PI/ low fill comes to mind though: if you say that a quick fill to saturate the puck is ideal, then the slayer shots are the exact opposite of that right? Because they give the puck a slow fill for almost half a minute

[@andrew.chinery]

I’m interested in this too - how do we know slow fill is bad? Is the explanation of it creating channels based on tests? I could easily imagine an explanation that goes “a sudden 9 bars of pressure disrupts the bed and creates channels, you want a slow flow that lets the puck expand gently”.

[@IanLandesman]

Thanks. I will experiment with quick flow beginning of shot for saturation purposes. I would like more info about this as watched that bit multiple times and am confused. Get pressure up, lever halfway down, when pressure gets low, lever up and gradually lower flow?

[@VivaLaKnox]

Hahhaaa, your squarespace transition made me laugh out loud in the subway 😅😂

[@LanceHedrick]

hahaha had to throw you for a loop!

[@AleX-je2sw]

Alright, might be a lame question, but I have one about low-flow pack saturation you discuss at about 14:00 mark. You've talked about how full saturation affects consistency and helps to avoid channeling. I'm interested in whether it affects the flow rate of the rest of the shot. The thing is, I've tried a similar sort of thing on my Flair Pro 2, and the water was noticeably harder to press through the puck after the preinfusion. I wonder if anyone noticed something similar, and, if so, why it happens.