ESPRESSO ANATOMY - Exploring Brew Pressure

When it comes to brewing coffee a lot of variables come into play, but espresso is unique with its use of high pressures. For a long time baristas have agreed on 9 bar as the ideal, but with so many machines offering pressure control, there seems to be so much more to the story. So in this video I test the same coffee on a variety of pressures to see how they compare.

↓CHAPTERS↓
[0:00] INTRO
[1:03] STANDART AD
[1:48] TESTING PARAMETERS
[3:12] FLOW & TASTE TESTING
[5:36] FINAL THOUGHTS

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#brewpressure #espresso #sprometheus

[JuliusSP]

Big take away for me is that the 9 bar shot still had decent complexity and cup quality while having the most body. This is why it is always the standard for shops due to all the milk drinks they are churning out at 12 to 16 oz. For a specialty shop not exceeding a 10.5 oz beverage 7 bars might be worth trying out.

[stuipooey]

That was super interesting and turned out to be a game changer for me. For some time now I have preferred the sweeter taste of my Picopresso to my ECM Synchronika. Brew pressure was running 9.8 bar and after a quick youtube video on how to adjust (shout out to WLL), I brought it down in stages. Around 7bar gave me the sweet balanced taste that I really like and the best shots I have had from this machine.

[seanwolfe]

I swear I watched a video by you that swore that 9 bar was the sweet spot. As someone who has been doing this at home for a long time, but never feeling I’m where I could be, I really take the videos of people I think know what they are doing to heart. I guess I need to adjust *again*, now to 7 bar & see what the hype might be about.

[CommentTaire]

La Pavoni lever here. I've been doing 6 bars for years. Actually, my La Pavoni has a hard time rising to 8 or above, even 7 is hard. So I developed a protocole (weight and grind) that works well at 6 bars, and I am extremely happy with the results. Semi dark roast, Tanzania Peaberry.

[robertebob]

Ok. I finally got Standart Mag. I couldn’t resist any longer. Merry Christmas to me.

[Weeem]

I was forced into this experiment when my last espresso machine got a fault.
Not sure if it was the OPV opening too soon of my pump was failing, but either way it was making shots at low pressures... and they still tasted pretty good :)

[karlmansson]

I'm a little confused. Pressure is a result of flow and resistance. You have to increase either to increase pressure. I'm not familiar with the rotary pump in the machine you are using but it's likely an OPV you are adjusting right? So adjusting that for a lower pressure just means you are diverting the flow through the pump into the OPV instead of through the puck. Grinding finer will bump the pressure up again for the same flow rate. But then again there are factors like the "water hammer". A high initial flow or onset of pressure will compress the puck and increase the resistance of it. A low flow shot with either OPV or paddle set to restrict will allow the puck to expand more, almost like a blooming espresso or Slayer shot.

What I'm saying is I don't think you are changing pressure on its own, you are changing the flow of water that is directed through the puck at a given pressure. When the puck "pushes back" with 6 bars, all water above that is in surplus to the water actually going through the puck is going through the OPV. Not sure if it matters in practice but it might be good to consider for people wanting to experiment. Pressure is resulting force of two other factors.

[Markusableitinger]

Like your experiments, conclusions, open questions, guesses. Add to the complexity different roast degrees. Would be great to explore the respective taste profiles and compare different roast degrees with same bar levels with each other.

[michaelt]

If 6 bars allows you to grind finer, will adding filter paper at the bottom of basket allows you to grind even finer and get a higher extraction?

[oscarzanette]

Extremely interesting video!
Would be interesting to explore past 9 bar.
Appreciate the good work

[阳明子]

Love single variable tests, thanks! Great video

[myname-mzlo]

i think that doing all these tests with the same basket is only a starting point . but with new baskets having all kinds of hole sizes and resistance, there needs to be tests that take that into account . seing if a 10 bar shot with a basket that has alot of resistance vs low resistance tastes better, since the grind size will have to change with both of those examples .

[mrhoborz]

I have an older gaggia where the OPV can be adjusted with an allen wrench... have it at about 8 bar, gonna have to try these lower pressures

[Monte]

Inspirational yes. Informative maybe. Suggestions include multiple shots at each pressure and blind tasting.

[eddieliao]

Very interering test. I reduced the pressure down to 7 bar (I usually used 9.5 bar). Taste is much more smooth.
Regarding to the test procedure, may I ask if you only adjust the pressure while keep other figure (grind setting, temperature..etc) the same? Thanks.

[caffeinated_slacker]

In my non-scientific exploration of this topic on a Cafelat Robot, I found that lower pressure shots (roughly 6-7 Bar) were sweeter and generally tastier than 9-bar shots.I’m looking forward to exploring this further on a Odyssey Argos lever machine, which can switch between 8 and 6 bar springs, or full manual.

[peterelliott]

Yeah I found that 6.5 bars (on my VBM) was great for a coffee I used to buy, but when I changed cities (and beans) 8.5 is better now. Also the old bean used to like a longer pull. So as you say get experimenting! Every bean is different.

[jorrit]

Thanks! Genius idea! The 7 bar shot taste a lot better than the 9 bar shot.

I have two questions: how many bars is the difference between the pressure indicated on the standard pump pressure gauge and the pressure in the brew group?
My second question is: is the rotary pump actually better than the vibration pump when it comes to the final result (especially the taste)?

I have a EMC Classika PID. And it has a vibration pump. I hope it is good enough for quality espresso.

[DuBstep]

you need to do this but with high pressure, since more is better.
9-15 bar :DD

[GadgetsGearCoffee]

Did I miss something? Is there no pre infusion in this test?