THE TRUTH ABOUT ESPRESSO: Understanding Espresso Flow

I take a deep dive on profiling espresso and look at terms like water debit and puck resistance. If you enjoy learning about or drinking espresso, I suggest you watch!
NOTE- The Decent Espresso Machine is not 100% on knowing input flow. It estimates the flow based off a complex algorithm. Supposedly, it has a 20% bias, which is quite impressive.
ANOTHER NOTE- Parts of the video sound like I am saying water debit is a constant throughout the duration of the shot. Please know that is NOT what I mean. The OPV not only shunts flow to bring pressure down, but the pump itself lowers the flow rate once pressure rises, hence my equating espresso flow with input flow.
Don't forget to like and subscribe if you enjoyed the video! Cheers!
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FREE Smart Espresso Profiler App referenced:
Google Play- play.google.com/store/apps/de...
Apple Store- apps.apple.com/us/app/smart-e...
Resource on Profiling:
espressoaf.com/guides/profili...

[@cheekster777]

Lance: Yo yo yo,

[@patrickcasper7487]

Aww yes, what you describe here is the outcome of fluid mechanics which so few videos explain. Liquid flow through a packed bed, which is typically modeled with the Ergun equation. You can set the flow, the pressure drop and the characteristics of the coffee bed, but if you fix two of the three then the third is fixed as well. Grind parameters and bed characteristics effectively change the void fraction, sphericity and particle diameter which are the inputs to the equation besides flow velocity and bed pressure drop. Really great video!

[@matthewjulius5401]

My sense is that we'll look back in 5 years to how we've thought about pressure the same way we look back at obsessing over shot times. Yes pressure (and shot times) are helpful indicators, but they're only a way of getting insight into the main variables we actually care about. In the case of pressure, an indicator for flow and resistance. For time, an indicator of dose:yield, temperature, and flow/pressure.

[@AndreGomes1987]

I'm not a barista, just someone who bought an espresso machine and decided to make good espressos and simple latte art. I was not able to come close to making shapes, not even getting the foam down at all until I found your channel. Now I can make hearts and I don't have many practice cups in. Your style of teaching is perfect for me and I'm so happy I found you. Thank you for all your work, the information is so valuable!

[@andreionutnegulescu1]

Hey Vsauce, Lance here!

[@olivierbinet6960]

What an amazing video… I never understood why everyone was crazy about setting OPV to 9 bars and where often on very geeky forums they would say that doesn’t matter, the grind size does. Now I understand: if the OPV kicks in at 9 bars or higher, well that means your flow will just not be right. So whether it hits 9 bars or not does not matter. THANK YOU. It was so good I’ll subscribe to your channel, it is my first subscription ever.

[@philmeyers9647]

If only all of the teachers of the world presented with passion and knowledge like this.

[@prika58]

Thanks man...nice workflow. There are differences in design of machines. OPV valve is a security mesure in commertial machines. They have a main water supply plugged directly to coffe boilers. Pumps are set to 9bars and OPV valve is set to 12-15 bar. If the pressure reach 12-15 bar,OPV will open and relase the pressure to the drain. Machines with vibration pumps and water tanks...the pump delivers 15bar. And OPV is set to 9bar. So it is constantly returning water to the tank. Hx machines also have restrictions in thermosyphon pipes to control the flow.. We had good and bad espresso 40 years ago and with all the new technology we still have good and bad espresso. Just enjoy and have fun. Thanks again for your point of wiew.

[@dailyhomebarista]

I was always struggling to dial-in espresso, and this video was so helpful to make me understand what is my machine is actually doing when we say it brews coffee with pressure haha. Thanks for this great video again Lance! It was super understandable and helpful! Hope you have a nice day, and cheers!

[@christianshobbies9292]

Wow. I just posted a homebarista post about water debit and this is by far the most comprehensive and thorough explanation on the topic I've found

[@fjaviergl99]

after years of using a LMLM i just got a Lelit Bianca to play with... this video was exactly what i needed!... keep up the good work

[@tobyr21]

Lance, I saw your video on turbot shots, and I found this new video to be ALSO very clear and easy to follow. Thanks! I have a Rancilio Silvia V6, which means that I cannot control either the water debit or the pressure limit, but it really helps to understand clearly that when I am adjusting (1) the grind and (2) the degree of tamping provided by y Distribution Tool and (3) the number of grams of coffee in the basket, that I am adjusting all these things to manage, not the pressure, but the water flow. - Toby (a subscriber)

[@EricMacam]

Awesome video! I finally decided to download the se profiler app. On the first go I decided to record the flow profile of my usual manual pull on my Flair Pro 2, which is essentially a slow decline in pressure after a preinfusion and ramp up to 8 bar. It was affirming to see I pretty much followed a constant flow rate after I reached the initial peak pressure. Excited to now use the app as a guide.

[@davidcheung9979]

Wow, that was super good and informative! Thank you Lance!

[@Mikey___]

Great video Lance, thank you - both the delivery of the content and the quality of the editing are awesome

[@axel.lessio]

Just applied some of this, had the best shot from a Barista Express yet, with slight but pleasant acidity, great sweetness, chocolate aftertaste that is lasting half an hour after the shot. You're a saviour! 😂

[@arch-rival5477]

I absolutely appreciate this video! Your summary at the end is fantastic. Thank you Lance!

[@yousifaldawas1005]

the only reason that make this easy to understand is you , I love the way you explain things really thank you bro!

[@yannicke5678]

Brilliant video! I’ve been playing around with my Bianca, trying to replicate some of the Decent profiles, too. Thanks to your explanation, I don’t need to worry anymore about not having understood the concept. You really break it down very well 😊

[@SanMartan]

Very good video Lance.. When you start playing around with pressure profiling and flow control it opens your world up..if you can use this on your machine the whole 25/30 second shot gets blown out the window