What is the best pressure for espresso?

[@bwilliams915]

On my Quick Mill Anita I found that 9.5 bars got rid of my channeling problem and produced a better cup. I went higher and lower over several months to come to this so for my skill level 9.5 has worked well for me. Great video. Thanks!

[@Biomechan]

For the pulsating pump machines, there's usually an overpressure valve which balances the pressure to a desired Bar level by returning part of the flow to the water canister. It works!

[@Gk2003m]

And as they age, their output pressure drops. This actually has ramifications for those seeking good espresso on the cheap. Locate virtually any ‘quality’ consumer espresso machine from a decade or two ago, and guess what? Your pressure at the brew head will be somewhere around 9 bar! Which is the Goldilocks Zone for espresso pressure. From there, add an unpressurized basket and you can control the flow merely by changing grind size. Just like with a $1500 machine.

[@Bloodysugar]

@@Gk2003m It is possible to use high quality OPV (which are not expensive) that wont ware off faster than professional machines, as they are the same used by these machines. Also such OPVs will allow to change springs, and as long as you got spare springs and clean the OPV once in a while it will work just fine for decades. When it comes to the pump the power loss isn't that much of a problem as the most basic ones will provide about 11 bars, giving 2 bars to lose without causing any pressure drop at 9 bars. It's really not an issue that will bug you as soon as it will start to ware. And if you're worrying about the flowrate diminishing, well that's in fact something to hope as vibratory pumps usually shoot around 200 cc/mn while a perfect espresso flowrate is around 67 cc/mn. You can lose half of the flowrate of a vibratory pump and still need a dimmer mod to slow it down (by losing some pressure by the way, more than pump's ware off will lose during years...). Changing puck's density will help but it's more of a micro adjustment that is useful to adapt to coffee types than a solution to correct big flowrate deltas. And if you really want to keep the pump at its best (for what it is and not what you need) you can keep the basic Ulka pump and change time to time it's internal gaskets (an o-ring and a ball) that endure most ware. Or you can swap it for a professional grade vibratory pump, like the ones Fluid-O-Tech produces, that will last way longer without as much maintenance. And of course if you take a 20 bars pump (which in reality is more about 16 to 18) you'll have even more room for ware to happen without any impact on coffee's quality. By the way I still don't know why most brands don't use Ulka E4 by default as it provides 20 bars and a bit slower flowrate for the same price as the E5 they put in almost every machine. Trouble with vibratory pumps is their fast flowrate, not their ware, their noise level (it can be hugely tamed) etc.

[@robertusga]

On the Decent DE1, it is very easy to dial in pressure at pretty much any increment you want and change during shot, lever profile style. Love it! Very easy to set favorites for all types of beans.

[@kraptor11]

Avoid all of these variations to the variables by using the Decent Espresso Machine. Do a 10s per-infusion, followed by increasing to 9-bar and then reducing the pressure to match the flow. I think if you want to expand your experimentation - that machine will give you a lot more understanding of coffee extraction than any of the commercial machines you are using. I watch your videos regularly so thank you for the good content.

[@HauntedSheppard]

I'll send you payment details so you can share your wealth and I can buy a Decent Espresso Machine. That way I can avoid these variations to the variables.

[@itsm3th3b33]

"... Increasing to 9 bars..." Why 9 bars?

[@kraptor11]

@@itsm3th3b33 below 9 bars the pressure isn’t strong enough to extract the best of the flavour. Beyond 9 bars the probability of the puck breaking up is very high, which leads to channelling, and then very harsh tasting coffee. The important thing is how flow of water through the puck is a better indicator of extraction. It needs to be even, and consistent across the puck. That’s why the lever shots taste better mostly. They are able to maintain the constant flow rate of water as the integrity of the puck changes through the shot.

[@charstar386]

@@kraptor11 Thanks for the useful information.

[@itsm3th3b33]

@@kraptor11 9 bar is what you say. But you provide no evidence. He did. In a very scientific and reproducible way. His video has value. Your comment is just your opinion based on hear say.

[@brekel42]

I'd be interested in seeing the results for 9 bar ±0.5, or ±1 rather than ±3. Also do you know, with your test machine, what the difference is between the pressure in the group head vs the machine gauge pressure at the normal flow rate? In my experience, the drop from the gauge to the group is different for different models, and at the end of the day it's the pressure at the puck that is the relevant factor.

[@SevenMilesCoffeeRoasters]

For this test's purpose we focused on what a Barista can see by the dial, but to be sure for exact referencing, a Scace tool is definitely useful/recommended in determining exacts!!

[@POLARISMAN81]

Please do more videos like this! Maybe a little more in-depth on the lower pressure and higher pressure to different temps an grind size with dose. Thanks these videos help a lot!

[@SevenMilesCoffeeRoasters]

Much more planned yet!! :) We're happy to share what we find! :)

[@tonymitchell1461]

Great experiment overall however the tasty results were undermined by not blind testing. It’s undeniable that preconceptions effect perceptions. Still really informative and worthwhile. Thanks

[@BosHK]

Very interesting. I just pulled a double (37g) from 18g of light roast beans I got using 6 bars, shot wise, noticed less channeling for sure, those subtle hints of berries did come through even with a small amount of milk added.

[@haberdashery314]

I really appreciate this kind of research. I'd also be interested if you can repeat this with the flair, which lets you measure pressure in the basket, the actual pressure applied to the coffee.

[@SevenMilesCoffeeRoasters]

We're definitely looking at the Flair 58. It's a great piece of kit!! But harder to control the pressure variables with a manual lever machine. You'll see it again on the channel! :)

[@HaveAGoodHeart]

@@SevenMilesCoffeeRoasters Hi I would be looking forward to that, as it is always tempting to buy a manual level machine like Flair 58 or Robot as it is so easy to maintian and the much shorter waiting time, though not really value for money, especially for the Flair 58... but i always wonder if manual level machine can produce consistent shots. On the other hand, it seems that even for semi auto machines without E61 groupheads will have challenges maintaining consistent temperature.

[@tommckenna5664]

Super interesting video guys, I love seeing these deep dives!

[@SevenMilesCoffeeRoasters]

More to come!

[@davidhayman9330]

Thankyou this was quite helpful, well thought through!

[@CommentTaire]

La Pavoni lever here (with pressure gauge on group head). I've been pulling at 6 bars for years. Actually, my La Pavoni has a hard time going above 7-8-9 bars. It can, but it's hard. I found a protocol (grind and weight) that makes a sweet dose every time. I also use a puck screen. Finally, pressure at the group head is always a bit lower than the pressure at the pump. So if my group head gauge says 6 (my sweet spot), a pump reading (that's my arm) must be a bit higher.

[@akquicksilver]

Great video! I've been dabbling quite a bit with my flow controlled Profitec Pro 600 and different roast profiles (home roaster). It has been fascinating to observe the differences that the roast, grind, and brew pressures make, not to mention temp variations. I believe one could spend years looking for the "grail". My set up has the OEM brew pressure gage which came from the factory with the pressure set at 10 bars. I dialed that back immediately to 9 bars. The flow control is an after market device that uses a gage installed directly into the brew group so I can monitor both pressures. I am slowly coming up with a feel for roast profiles, grind, and flow profiles. I primarily have learned to just observe the color and texture of the flow out of the portafilter as I watch the rate of flow and I've become pretty efficient a pulling consistent shots. It is fascinating and fun. Please keep these types of videos coming!

[@andreasbaglamopektis3584]

Appreciate the controlled study. My Rocket Giotto V reaches 8 bar pressure. How do I adjust to reach 9 bar? Do I need to open device and get into the guts of the machine?

[@telurkucing5006]

I found my cheap vibrating machine works good from 9-11 bar lower than that it flows quicker taste very sour and above that taste little bit harsh still drinkable but channeling worsen it literally spray around the bottomless portafilter like parfume

[@dsmpampis]

Great video. I have a Rocket Appartamento and from the factory the pressure it is around 12bars. I was making espresso for the last year with 12bars and before some months ago a changed it to 9bars. The extraction time was almost the same but the taste was better, especially with milk(flatwhite, cortado etc) and also the espresso is not so acidic.

[@jdpst20]

Hey I've been hunting around for info on this and recently came across some Videos and some upgrades... I too have the Appartamento and have had it since 2017 and never knew any better even that it was set to 12 from factory... I recently upgraded my grinder to a Silencio and I have it set really low and still 20g in yielding 40g out brews pretty quickly "timing started at 1st drip" You are saying extraction times are relatively the same... Should I grind finer or just tamp harder? I am waiting on my pressure gauge and water temp gauge to get here and I also ordered a IMS screen. In my mind lowering the brew pressure will "slow" down the extraction but this video is showing the opposite and what you are saying... I just don't get that slow drippy extraction that you see in so many naked basket videos. I'm trying to shoot for that 30 second extraction but to get a 1:2 brew ratio it's almost impossible I'm more like 1:3 or even 1:4.

[@jamesfletcher474]

It's unlikely the factory settings were at 12bar, more likely the internal (or external) pump is set a little too high and wasn't setup right when first installed

[@mrbr1dges]

Appartamentos are factory set to 12bar. Make sure you’re using good coffee. Like fresh 7ish days off roast. Devocion from NY is my goto. Wild Forest. Work on consistency. Use one of the palm tamp/distributor combo. Removes the variables. I’m having good luck with a cheap Amazon puck screen too. Pucks come out dry with 18g on the standard basket and bottomless PF. Get a temp gauge for the GH. Mostly likely pulling way too hot. Hang in there. I was pulling consistently even at 12 bar - like it better at 9. Now working on temp consistency.

[@cpg8000]

Wonderful content. Thank you very much for the education. Cheers!

[@SevenMilesCoffeeRoasters]

Our pleasure!

[@Thatdadbodreal]

Great video Josh! Killing it brother

[@SevenMilesCoffeeRoasters]

Cheers bro!! :D

[@Squilliam-Fancyson]

Pressure typically not ajustable with vibratory pump machines? As far as I know that at least most 1200$+ vibra. machines got an expansions valve with return line. Depending on the manufacturer these expansion valves can be set easily without disassembling anything(like on ECM machines). Good expansionsvalves are able to hold max. dialed in pressure perfectly without any pressure spikes or drops. Of course vibra. pumps still got the noise disadvantage as well as the delay until back pressure is build up(somehow of a pre infusion viewed positively), but otherwise they do not make lesser espresso compared to rotary pumps.

[@Glormpo]

Adds a layer of complexity, but I’d be interested to hear about how playing with ratio changes all this. Most people seem to have good results with low pressure plus longer ratios

[@SevenMilesCoffeeRoasters]

Yes, agree. so many things that could be tested.

[@pureno1z]

@@SevenMilesCoffeeRoasters mainy people believe, incorrectly that you can only change one variable at a time. This is not true, in my experimental design course at University, we looked at a process called split-plot design. This allows you to estimate the effect of each treatment in your design, without having to run every possible combination. They reduce costs but allow you model the setup. It is fairly common approach when you have many different levels to a each factor in a design.

[@Gk2003m]

If I bring is ideal, then the ideal ‘entry’ machine for an aspiring barista is an inexpensive, used vibration-pump espresso maker from 15-20 years ago. As the internal seals wear with age, the output pressure drops. No longer at 15-16 bar, they are now around 9 bar at the brew head.

[@450gmo]

Great vid. OK... logically the next video will be about pressure profiling for manual machines (e.g. my Cafelat Robot matched with a Niche Zero).

[@skatcat31]

I wonder what would happen if you measured the flow rate through the dose itself? I remember reading somewhere that the average pressure drop over a 58mm group head is pretty consistent and that setting it to 9 or so at the pump would lead to a different pressure at the dose itself, and going much high would inhibit flow. Probably could test this with a flow meter basket. For some reason, I remember 6 bars through the dose was what usually happens through a 58mm at 9 bars gauge?

[@pierrelouismarketing]

Guys, I love your videos. Could we get one about manual espresso machines? I have a ROK and I am struggling to get consistent shots…after watching ALL the videos about the ROK on KZbin lol thanks!

[@SevenMilesCoffeeRoasters]

Great suggestion! We will definitely look into it :)

[@wakeawaken430]

My vibe pump'd Rancilio epoca St1 needs opv to set with blind filter to 12.5 bar, if not the espresso is disgusting It would be nice if you make the same test with a vibe pump machine

[@vicjsch]

That was great! Thank you.

[@michaelmott3083]

It looks like the extraction times are not linear with the dose size. As with 9-bars, 20-30 seconds is the canonical brew time for a good extraction. Your charts suggest there may be an optimal interplay between pressure, dose size, and extraction time. Have you thought of looking into that?

[@SevenMilesCoffeeRoasters]

Certainly, all things can be adjusted, to create different experiences. I've had plenty of cracking good espresso's at 9bar with a 60second extraction. whilst 9bar for 20-30 is most common indeed. There's many things we're looking to at the moment, but as a 3D experiment as you've suggested above, we haven't started that one yet :)

[@kitsatya7801]

I used De’Longhi EC9355 and so how can I adjust pressure ?

[@fahadara]

So what pressure we should aim in a vibrating pump machine? 9 or slightly more?

[@jadoei13]

Usually 10 bars against a blind basket, giving you 9 at the normal flow rate of espresso. That would vary a little bit depending on what your desired output is and from machine to machine so just see what works best for you

[@fahadara]

@@jadoei13 🙏🏻many thanks

[@Ahmad_faf]

what to do with grind seeting to lower the bar pressure, i got like clos to 15 bar pressure

[@kwfown]

I adjust pressure on my machine through dialing in using a mixture of grind size and volume. It’s a set and forget as long as I’m using fresh beans, however if I were to change brand, then I might have to tinker with it a bit. Question though, does the course/fineness of the grind have an impact on the taste?? Mine is unusually low/fine, around 2

[@CTULProject]

Excellent

[@healthamongstus710]

The area you said click right here to see the other videos, aren't showing videos. Nowhere on the screen do they show.

[@williaml2579]

what should the pressure be on the "Flair" to be similar to 9 bars on a La Marzocco?

[@TimidTuna]

Well made and interesting video! Does anyone drink straight espresso down under?

[@SevenMilesCoffeeRoasters]

yep, sure do 👌

[@ddiesel1836]

is espresso extracted at 4 bars still safe to drink?

[@MagnusWurzer]

OK, but what about 8.5bar or 9.5bar? Going up/down for a whole 3bars seems extreme.

[@SevenMilesCoffeeRoasters]

Yes, there's aways more we could test - and it is difficult to pack everything into a short summary like this. The initial goal was to see if we could determine any difference at all at higher/lower pressures, hence the larger increments. So a next step might be to look closer at smaller increments and how they might benefit specific types of coffee / roast colours.

[@NashvilleFanatic]

Yeah! The even slight mixed results seem like good reason for more testing between 9 and 11.

[@robwatumd]

@@SevenMilesCoffeeRoasterscan you do another really dialing in between 8, 8.5, 9, 9.5, 10?

[@BensCoffeeRants]

Could have just used a cheaper E61 group machine with a pressure gauge mod for the brew group!

[@Hello-itsme9]

10 bar for rancilio silvia works for me

[@danizanzibar4344]

The intro tune sounds somewhat like Oneus - Valkyrie, thank me whenever

[@kennypark2101]

No, when i decrease my pressure in machine from 9bar to 6bar, the velocity drops down, so the shot time was longer. This is opposites to what you have explain in this video. Why that?

[@toddredlin5634]

My Mara X came set at 10 bars and when I watch other videos on this machine it seems they all are set at 10 bars being fairly new don’t want to void warranty by changing So question is would one bar make a difference in shot?

[@SevenMilesCoffeeRoasters]

Every variable does produce a difference in your shot, even 1 bar of pressure, let alone a single gram in of coffee or espresso out, even temperature a degree up or down will create a different experience, and that is where the beauty and endless fun of espresso lies. But all things to your preference, what I may enjoy and you enjoy are different, and that is OKAY!! :D

[@gplusmpaper7123]

It seems that its 10 bar of pressure at the pump level. At the group head drops 1 bar so becomes 9. I sow that in a lelit insider video when testing their machine.

[@Tthug_93]

I git 13 bar in my machine café expresso Is that normal ?

[@MrFloris]

I saw this video, and now i want to see all your videos, there goes my thursday night i guess ( TO THE IPAD .. dun dun dun)

[@joellindsten424]

I'm having 9 bars on the machine but higher in the group head, like 11 bar. Should it be like that or is there something wrong with the machine? It's on a ecm technika.

[@SevenMilesCoffeeRoasters]

Pressure quite often can be different depending if it's being choked by a restrictor setup to control flow rate & such. IF your coffee tastes weird you can adjust the pressure, but if the flavour is excellent, then don't fix what isn't broken! :)

[@tonylawlor8833]

This has been done time and time again over the years. Don't you think machine manufacturers have done this, yes they have with the best of tools.Plus home espresso machines have been testing this for over 30 years.

[@superduperultraben]

how about turbo shot? which normally around 5-6 bars only?

[@SevenMilesCoffeeRoasters]

Everything is variable, so dialled in, it can definitely be tasty, but this was pressure test only :)

[@paoloteves2462]

How about 15 bar? Can you make a good espresso with that?

[@wolframluchner5316]

Interesting. I found this on Reddit: „Vibration pumps are set to more than 10 bars because it works better his way. "Its like a toy, so you have to increase - a little bit - the pressure" Source: Luca Bezzerra. kzbin.info/www/bejne/e2XcZWB7Z8Z_abc edit: thats the great-grandson of the guy who invented the espresso machine“

[@ericpmoss]

I think your logic of gas restricting flow doesn't make sense. Liquid flows right through a gas. What might be happening is that the stale coffee is less oily (or has oxidised oils) that don't seal spaces in between particles, and/or don't let the puck compact as much. Higher pressure might simply be compacting the puck more.

[@SevenMilesCoffeeRoasters]

Stay tuned, as we explore this theory more in a different video :) But definitely an interesting point you raise!! :)

[@vegahimsa3057]

Less gas or more brittle charcoal fines?

[@SevenMilesCoffeeRoasters]

Not sure, what particular context you're referring to :)

[@vegahimsa3057]

4:45 ish: "our theory ... CO2 gas is responsible for pressure" as opposed to liquid more easily flowing through brittle (charcoal like) old coffee grinds

[@PhaTs00p]

It's the same music as Leon the Lobster!

[@temmie-shop]

Why home espresso machines works with like 19, 20bars?

[@blizzbee]

I prefer around 10 - 10.5 bars and I decided purely by the taste in the cup from months of experiments, tests, repetitions, beans, etc. 9 bars, to me, doesn't goes well with light roast coffee while 10.5 can makes any roasts delicious.

[@gbf5972]

Interesting! What machine are you using?

[@blizzbee]

@@gbf5972 bezzera crema

[@Sunshrine2]

Hold on. 4:42, you claim the extractions behaved the way "we would expect", which is higher the pressure, lower the time. But then the graph shows exact opposite - both linear interpolations show that both fresh and stale coffee extract slower the more pressure is applied. (Both graphs have positive slope, although the "stale" function 'derivative' is 1/3 of the "fresh" one. But the progression is the same!)

[@ericpmoss]

Do you think that Italian roasters dialed in their bean choices and roast profiles to work best with the levers that dominated the industry for the first 50+ years?

[@wakeawaken430]

With the pressure profile of a lever machine, I mean with the spring (bezzera strega), not la pavoni, the Italian (dark) roast comes out more sweet and balanced

[@SevenMilesCoffeeRoasters]

Highly possible! :)

[@roslishirlinshoots5846]

Me watching this while making coffee with my budget coffee machine that has 19bar written on the box

[@Dejan_23Unlimited]

Controlling pressure is extremely crucial for the Amazing Espresso * Slayer anyone 👍🏼 Set up and having the same pressure for the shot is just ok, but not great espresso. Think again why super expensive specialty Coffee is not make on La Marzocco 😉

[@SevenMilesCoffeeRoasters]

I'd counter, expensive specialty coffee can be made on almost any machine, but having extra variables means yes, I agree, you can definitely create a unique experience!

[@Dejan_23Unlimited]

@@SevenMilesCoffeeRoasters 👍🏼☕️🙏🏻

[@1945sas]

errr...my Giotto Rocket runs perfectly on 1 ...get it...1bar. Why do you need 9-15 bar?

[@80goal]

I'm not sure why you need to adjust your pump. To have more pressure, you need to increase the resistance the pump will see at its downstream this means go finer grind and the pressure on the coffee will increase. The question will be, is your pump capable or not to go to 12 bar? And the flow will be reduced, so you will need to increase your shot time to have a cup of espresso. To reduce the pressure, it's extremely easy, go coarser grind, the pump will see less resistance at its downstream, and the pressure applied on the coffee will be less than 9 bar and the extraction speed will be faster

[@mcfly6161]

Better video would’ve been to adjust your grind with different pressure to get the same extraction time and then compare.

[@caleschley]

Normally your biceps don't directly create the pressure in a lever machine. You biceps charge the spring that will precisely create the pressure. Like you mentioned, the flair doesn't have a spring so in that case biceps are creating pressure directly 😂

[@noahmn4985]

Its the triceps in manual espresso makers😁

[@ioandavies8423]

He looks just like David Mitchell from Peep Show

[@SK_SANOWAR_786]

So basically pressure was 8_9 bar it's okay, midium to dark roster beans used for my machine,..!!! It's okay 8_9 bar pressure?

[@reasonlogic8816]

So, 9 bars?

[@justinus]

it's triceps btw

[@SevenMilesCoffeeRoasters]

I guess that explains why I don't look like Chris Hemsworth

[@plurplursen7172]

With no pressure, we would call it eso...

[@pazuso]

When testing perfume you sniff coffee to reset your nose. When testing coffee, do you take a shot of perfume to reset your taste? 😶

[@HitsandHeadlines]

I like 15 🤤

[@sluive3228]

Could also be that your grinders are "biased", meaning they're especially engineered to produce a particle size distribution and particle geometry that fits a classical 9bar extraction the best. It's a really tough theory tho, since testing for it would need adjustments of the burrs or a sifting session where one would look for a pairing of the perfect particle size(s)/geometry for each pressure.

[@SevenMilesCoffeeRoasters]

It's definitely a possibility. Another possibility is that because we use machines set to 9 bars as part of the tasting/development of our espresso blends, they end up optimised for this pressure - like a self-fulfilling prophesy...

[@sluive3228]

@@SevenMilesCoffeeRoasters The idea above came to me when I played around with my grind distribution for espresso, so I recently started adding fines. The yielded shots taste way better at low pressure (4 to 6 bars) than a normal grind without added fines. Currently I'm working with 12g doses containing 2g added fines. I find that fines from lighter/medium roast tend to give a better flavor, but I haven't done enough research yet. I've currently 2 ways of creating fines: 1) using fines from sifted filter coffee (not older than half a day) 2) grinding on half the grindsize I grind for espresso The second one is more accurate, also it does increase consistency, since the fines don't lay around that long. On another note, my espresso setup may seem kinda weird (12g), which it actually is. So it just may be my setup that causes these differences in perspective. Just imagine a senseo switch modded in a way that it can produce bottomless espresso. (if 4 to 6 bars seems as an acceptable range for espresso to you 😉). Probably getting a flair58 soon, just for more advanced testing possibilities.

[@Masteryoda1982]

Adjusting the grind and tamp is so much less technical. Clearly something gen Z lacks finesse in. Brewing at 12 bar requires a courser espresso grind and compact tamp. 9 bar a finer grind closer to Turkish grind and light tamp. Italian espresso was perfected in the 70’s before my generation was even born. You don’t need software complex enough to land Apollo 11, you simply need to have knowledge from someone out of the manual machine era.