# Espresso Brew Pressures



## Tim95 (Jan 9, 2021)

Hi everyone - I would really appreciate your views and insights into some affects of brew pressure!

Using my MaraX straight out of the box I found the brew gauge was reading about 10bar during a shot and I was enjoying shots most at around 42 seconds using around 13 on the Niche zero. I'm very much an amateur, but I found I needed these shot times to balance out some harsh acidity.

I then decided to play and reduce the brew pressure to 9bar, and was a little surprised at the result... Using the same grinder settings I'm getting 40grams out of 19 grams of coffee in around 33 seconds, but I had expected these shots to take longer. I feel like I'm getting more sweetness in the cup but also more acidity, which is on the verge of being yummy. (i.e. sometimes yummy acidity, sometimes a touch too much for me). I also found that grinding finder seems to lead to channeling and less balance.

I have a couple of questions!



Why has reducing the pressure increased flow? I'm leaning towards not compacting the puck as much and so allowing easier flow? Is there a sort of bell curve of flow vs pressure, and where do people think is the optimum?


Does acidity always come hand in hand with sweetness? I love sweetness in a shot but can't cope with much acidity. Any recommendations for technique or anything here?!


Thanks in advance - I look forward to your superior wisdom!


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## Mrboots2u (May 10, 2013)

Coffee is a fruit so always has some acidity to it, some origins less so than others and the darker the roast the more that acidity is masked to some degree and its a fine balancing a it between this and roast ( for my palate at least )

so perhaps look for Brazilians or blends that denote sweet notes ( chocolate ) and has less fruit forward notes .

For me a good shot has a Balance of both but everyone is different.

I wouldn't fussed to much about the optimum pressure, as it can be somewhat subjective ( I used to run at a flat 6 bar for many years for instance ) rather focus on what you are making that you enjoy and repeating it .


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## Richard H (Jan 31, 2021)

Hi Tim,

I'm sorry, I can't help you as to regards changing pressure with your machine.

To try and answer Question 2. I would have said that you seem to be grinding very finely and, possibly, over extracting the shot. Maybe, try for a slightly, coarser grind.

Keep your tamping, firm and even to avoid channelling.

I am also, always in pursuit of that sweet spot in the cup - hope this has been of some help to you.


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## Mrboots2u (May 10, 2013)

Richard H said:


> Hi Tim,
> 
> I'm sorry, I can't help you as to regards changing pressure with your machine.
> 
> ...


 It's highly unlikely that a brew ratio of 19>40 over 33 seconds is going to be " over extracted " is the sense of measured by extractions yields with a refractometer.

What makes you think it would be 21 % plus extraction yield From the data provided ?


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## Richard H (Jan 31, 2021)

Hi,

I'm only going by what I have experienced brewing my cups. It may be that I should try for a finer grind, and longer brew time to get better results.


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## Mrboots2u (May 10, 2013)

Richard H said:


> Hi,
> 
> I'm only going by what I have experienced brewing my cups. It may be that I should try for a finer grind, and longer brew time to get better results.


 May I ask Are you measuring extraction yield via a refrqctomter or making an assumption based in taste profile


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## Tim95 (Jan 9, 2021)

Thanks both for the advice. Comparing my grinder settings to other users I did wonder if I was going too fine, but I don't think the flavours I'm getting point to over extraction. Possibly the opposite!

Do either of you use the MaraX? I wonder what people's opinions are on brew time given the very slow pre-infusion.

@Mrboots2u - I agree about going on taste preference - I was just wondering how people have found pressure changes the flow and thus the taste in the cup.


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## Richard H (Jan 31, 2021)

Hi,

I'm don't have a refractometer and am making an assumption based on taste profile, alone.


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## Doram (Oct 12, 2012)

Tim95 said:


> I then decided to play and reduce the brew pressure to 9bar, and was a little surprised at the result... Using the same grinder settings I'm getting 40grams out of 19 grams of coffee in around 33 seconds, but I had expected these shots to take longer. I feel like I'm getting more sweetness in the cup but also more acidity, which is on the verge of being yummy. (i.e. sometimes yummy acidity, sometimes a touch too much for me). I also found that grinding finder seems to lead to channeling and less balance.


 One thing that may be happening is that if your grind is too fine you will create a barrier that the water can't pass through easily, until the pressure gets too high and you get a channel. This way you can get a shot to be faster instead of slower, and you can get sour tastes where you didn't expect them. It can be quite confusing, as you get results which are opposite of what can be expected.

If you have a bottomless PF, it can help you see what's going on. In any case it could be helpful to try a coarser grind to see if it helps, even if only to rule out this issue.


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## Tim95 (Jan 9, 2021)

Hey again,

I have tried reducing the pressure further so the pump is currently running just under 8 bar and I just can't get slow shots. I've tried WST tools, different grind settings etc but I get channeling every time.

There is definitely less channeling if I go finer but the shots are still too quick for my taste. Any ideas or advice?!


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## 27852 (Nov 8, 2020)

Question - why is time your primary metric? The only situation in which I would optimise for time would be for a video. However I don't watch coffee, I drink it - so I'd rather use taste as my guide. Time can be a useful indicator, but only as a very rough guide (e.g 2:1 recipe in 20s is likely to be overly sour and 45s be bitter for my grinder/machine set up).

As others have said, you can grind finer, but that is limited up to the point that you go too fine, cause too much pressure and channel/fracture the puck, which will cause a confusing mix of simultaneous sour and bitterness as the channel extracts faster than the rest of the puck.

It sounds like you have got yourself into a muddle with respect to grind. Perhaps it's worth restarting the dialling in process. Pull a shot which is obviously too coarse/fast flowing and then tighten up by a number or 2 (on my mignon I would go by one marker on the adjustment wheel) so that you get a shot that barely extracts. Your sweet spot is between those two values, definitely not finer than that.

if you have a shot you are largely happy with but is a bit sour, maybe run it to a longer ratio to say 2.5-3:1. Sour compounds extract first and bitterness appears last so running the pump longer may be the key to a bit more balance without adjusting the grind.

I think fixing the grind is an easier adjustment to make before considering brew pressure.

Good luck!


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## Tim95 (Jan 9, 2021)

Thanks for your message. I'm not overly worried about time, but I think it's a useful measurable to describe what's going on.

I will try to completely start dialling in again as you suggest. My current trouble is that I can't get a shot that barely extracts as it's channeling too much, but I'll go super course and start again.


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## 27852 (Nov 8, 2020)

Tim95 said:


> Thanks for your message. I'm not overly worried about time, but I think it's a useful measurable to describe what's going on.
> 
> I will try to completely start dialling in again as you suggest. My current trouble is that I can't get a shot that barely extracts as it's channeling too much, but I'll go super course and start again.


 Good luck. What coffee are you using? I've broken my head open trying to dial in some coffees for espresso and just realised I'd be better off drinking it as a pourover because I'd have to change too far away from my baseline "happy place" set up.


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## Tim95 (Jan 9, 2021)

I'm currently on Los Breritas from Square Mile. I think I'll try something darker than I expect I would like to see if that helps me get the flavours I'm looking for.

I'm still early on my coffee game but I seems I prefer light roasts for v60 but I crave a really thick and chocolatey espresso first thing.


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## Mrboots2u (May 10, 2013)

Tim95 said:


> I'm currently on Los Breritas from Square Mile. I think I'll try something darker than I expect I would like to see if that helps me get the flavours I'm looking for.
> 
> I'm still early on my coffee game but I seems I prefer light roasts for v60 but I crave a really thick and chocolatey espresso first thing.


 Is that Sqaure Mile one of their espresso roasts ( cant see it on website )

SQM espresso roasts are fairly forgiving and not that light tbh , in comparison to a lot of roasters. Doesn't mean they are a good fit for everyone though.

A decent mid roasted high quality Brazillian or blend would be worth a shot.

If you want more mouthfeel than perhaps go shorter than your 1:2 ratio .


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## Tim95 (Jan 9, 2021)

Sorry. Las Brisas and yep it's one of their single origin espresso roasts. Maybe they have run out now.

thanks for your help there. It sounds like it could just be my technique causing a lot of the issues. I do tend to buy every recommended tool to try to fix the problems and wonder if I'm muddying the water too much and over complicating things!


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## 27852 (Nov 8, 2020)

For chocolate/nut notes look toward Brazilian. I finished a bag of Black Cat Fazenda Terra Preta last week and that was excellent. I've got a bag of their Chocolate Point which I'll probably get to next week - will report back.


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## PD2020 (May 27, 2020)

Hi @Tim95, I'm also struggling to get a good shot with my Marax&Niche. Have you made any progress on this one?


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## PD2020 (May 27, 2020)

Mrboots2u said:


> It's highly unlikely that a brew ratio of 19>40 over 33 seconds is going to be " over extracted " is the sense of measured by extractions yields with a refractometer.
> 
> What makes you think it would be 21 % plus extraction yield From the data provided ?


 @Mrboots2u, I'm also on Marax&Niche and I have measured my shots with a VST Refractomer (yup, I followed the protocol).

This is with Black Cat Koke Ethiopian Natural.









Brew Ratio of 1.98 (18->35.7g) gave me EY of 21.44% (incl. CO2 and H2O adjustment from the VST app) with a shot time of mere 18s. All the shots tasted ashtray though.

I generally find it difficult to get below 20% EY at the ratio 1:2 and going 1:2.2 or higher gets me towards 22-23% rather quickly (all that with shot times well under 30s). Ashtray, salt and sour are common notes.

31s-long shot of 1:5.34 got me to EY 25.38% (Black Cat Pacamara)

I don't know if that's normal for other people but I suspect @Tim95might be in a similar position.

Where do your 1:2 shots average EY-wise, @Mrboots2u


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## MWJB (Feb 28, 2012)

PD2020 said:


> Where do your 1:2 shots average EY-wise


 To be honest, I don't think that Black Cat Koke (or any Koke Yirg I have had lately) is a good candidate for a 1:2 shot.

I got best results at 1:5 (whereas Signature gave good results at 1:2.5 to 1:3.5 ~19%EY) , though I could extract the same for the Koke (~22%) at 1:3 upwards. It's probably better suited to manual immersion brews & longer shots, than short shots.

It's the EY of the better tasting shots that should be the focus, not maximum EY possible, nor EY of unsatisfying shots.


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## Mrboots2u (May 10, 2013)

PD2020 said:


> @Mrboots2u, I'm also on Marax&Niche and I have measured my shots with a VST Refractomer (yup, I followed the protocol).
> 
> This is with Black Cat Koke Ethiopian Natural.
> 
> ...


 Are these shots filtered before being refracted


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## PD2020 (May 27, 2020)

Yes, they are indeed. I followed the protocol as in https://cdn.shopify.com/s/files/1/0092/7622/files/Syringe_Filter_and_Measurments_v3.pdf?123

As MWJB said, mind you these shots did *not* taste good. I just posted them as a reference: shot time of around 18s as a (admittedly poor) measure of resistance vs EY.


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## Tim95 (Jan 9, 2021)

@PD2020 I'm afraid I don't use a refractometer so I can't comment on extraction, other than by taste.

I've had some decent results using a darker roast, such as Pact's Bourbon Cream Espresso blend. I think I prefer the flavour of a lighter roast brewed well, but I find it much easier to get anything decent enough out of a darker roast. I've been ramping a little lighter and getting ok 1:2 shots in around 35-40 seconds. What concerns me is in grinding at around setting 10 on the niche. I know the calibration is a little subjective but it seems a lot finer than I've read other people use.

I still get extreme channelling with some shots though, which I never really had when I used a 54mm machine. I'm also at around 7.5 bar at the moment. I feel the shots are a little duller than the "out of the box" 10 bar pressure, but I'm enjoying experimenting.

Have you managed to get anything tasty with the niche maraX combo?


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## PD2020 (May 27, 2020)

I'm still learning but there are people in here who are very happy with their shots on this setup, so fingers crossed the stars align one day 

If you're talking about 1:2'ish shots, then I've had success only a few times. I've personally never had anything tasty around 40s, unlike some people, but I'm a newbie - please don't use my shots as a reference 😉

If you like lighter roasts, it seems not uncommon to target longer ratios like 1:3 (or even 1:5) which have the potential to extract more flavour and less defects - at the expense of texture. Depends on the beans.

No reason to worry about the setting on Niche - it can be anywhere depending on the calibration, beans, roast level, etc... As long as it stays consistent it's all good. You can also try cleaning the grinder and recalibrating it but at the end of the day it's just a number.

I'd be super grateful if we could stay in touch in case either of us makes progress  If they can send a bloody selfie-taking robot onto Mars, then surely there must be a way for us to make some nommy coffee one day 😉

By the way, do you use a stock basket or something else? And how much do you dose?


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## Tim95 (Jan 9, 2021)

PD2020 said:


> I'm still learning but there are people in here who are very happy with their shots on this setup, so fingers crossed the stars align one day
> 
> If you're talking about 1:2'ish shots, then I've had success only a few times. I've personally never had anything tasty around 40s, unlike some people, but I'm a newbie - please don't use my shots as a reference 😉
> 
> ...


 That sounds like a good plan! I'm very much a newbie and just trying to blindly find my way through!

I'm using an 18g VST basket and dosing about 18.4g currently.

With your comment about 40s, do you mean you have preferred slower or quicker shots?

I also wonder if part of my problem is I actually have very little experience of what a really beautiful espresso should taste like, as I only started making/drinking espresso in lockdown 1.0 and only really have my own brews to go off.


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## PD2020 (May 27, 2020)

I'm a coronial myself as well 😉 Bought my machine back in June 2020 to get these chocolatey lattes that I was missing 😉 But then discovered that fruity coffees exist which blew my mind 😉

Interesting, I'm also on 18g VST (I've been trying dosing 17g, 18g, 18.5g mostly).

40s has always seemed very long for me. I haven't had the feeling that going as fine as 40s was improving the flavour. In fact it felt harsher and harsher to me and (less importantly) it felt like the coffee stream on the bottomless portafilter would struggle to form. But then many people on the forum have reported success with 35-40s window (and slightly around it) so possibly I'm doing something differently.

An example of a tasty shot I pulled in January - Ethiopian Washed Chelbesa, temp setting 93-94*C, VST18 dosed 18g, output beverage 54g, shot time 31s. I tried to repeat it but couldn't. I had some other okay shots afterwards but that particular one was more than okay 😉

Glad to hear you're happy to keep in touch. Hope we can crack this one.


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