# MaraX questions about basket size, pressure drop and technique



## Santanor

Hey! I've been using my MaraX with a Niche Zero for a week now and I've got a few questions that I wanted to put out here to see if anyone has some feedback or tips, Basically:



I'm doing 18g coffee in. Which basket should I use? Medium or large?


Is my grind too coarse? I get 36g out in about 25s without manual pre-infusion.


Am I tamping with too much force?


The pressure drops during the process, is that normal?


I've recorded a small video (Sorry for the horrible Spanish accent) that hopefully helps to showcase what I'm on about 

The machine it's in "brew priority" and "hot" settings, if anyone is interested.

Let me know what you think, tips, feedback or anything!


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## MediumRoastSteam

You are using the right basket for 18g.

pressure is fine. You are grinding too coarse, the puck is offering less resistance as it gets extracted. You need to grind finer.

ignore the middle position in the lever. It does nothing on your machine. Start timing from the moment you move the lever from the lowest position (off, all the way down) to the brew position (on, all the way up). Don't park in the middle!

aim for 30-35 seconds, adjust by taste.


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## Santanor

MediumRoastSteam said:


> You are using the right basket for 18g.
> 
> pressure is fine. You are grinding too coarse, the puck is offering less resistance as it gets extracted. You need to grind finer.
> 
> ignore the middle position in the lever. It does nothing on your machine. Start timing from the moment you move the lever from the lowest position (off, all the way down) to the brew position (on, all the way up). Don't park in the middle!
> 
> aim for 30-35 seconds, adjust by taste.


 Thanks for the reply!

The middle position does nothing, but a bit up from the middle position water flows and the pump it's still off, I checked without the portafilter. Should I not do a preinfusion then? The one the Mara does seems too short

If I go finer then the pressure goes well beyond 9 Bars, how can I go finer and still hit 9 Bars? Less tamp pressure? Or should I not worry about the 9 bars? I thought that was a nice way of telling....


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## MediumRoastSteam

Santanor said:


> Thanks for the reply!
> 
> The middle position does nothing, but a bit up from the middle position water flows and the pump it's still off, I checked without the portafilter. Should I not do a preinfusion then? The one the Mara does seems too short
> 
> If I go finer then the pressure goes well beyond 9 Bars, how can I go finer and still hit 9 Bars? Less tamp pressure? Or should I not worry about the 9 bars? I thought that was a nice way of telling....


 all you are doing is wetting your puck with tiny amounts of water from the thermosyphon, under no pressure. On a plumbed in machine, I can see they working. Not on your machine. Watch the pressure as the pump ramp up. It's nice and gradual. There'll be a brief pause around 3 or 4 bar, and that's the E61 pre-infusion chamber doing its job.

Pressure will go up to 10 bars, which is absolutely fine. This is controlled by the expansion valve.

You are focusing on pointless things, honestly. Focus on 18g in, 36g out, in 30 to 35 seconds. Get that right, and then worry about pressure and what nots. 😉

Also, I noticed you touching the group when the machine should be up to temperature and ready. How long are you warming the machine up from cold? You need around 35 minutes.

did you read the in depth review of this machine?


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## Rob1

The pressure will drop a little as the puck erodes which is normal. If you are getting much above 9 bar then you should alter the OPV. I think on my machine it's set to 10 bar with a blind filter. Tamp pressure is probably not relevant and don't worry about metrics like time and pressure too much so long as they're ballpark e.g 25-45 seconds 6-9 bar etc.

Don't half lift the lever as it doesn't do anything useful and potentially messes up the temp control in the HX. It isn't a "manual pre-infusion" position.

It's not possible to tel you whether your grind is too coarse or fine without tasting the result, so you have to decide yourself based on how the shot tastes if you want to go finer or coarser or increase or decrease yield.

Also don't leave the portafilter sitting out of the group as it should be the same temp as the group after pre-heating in there for about 45 minutes on a standard E61. Fill with coffee, tamp, put it back in and pull the shot, the quicker you are with this process the better.


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## Santanor

MediumRoastSteam said:


> all you are doing is wetting your puck with tiny amounts of water from the thermosyphon, under no pressure. On a plumbed in machine, I can see they working. Not on your machine. Watch the pressure as the pump ramp up. It's nice and gradual. There'll be a brief pause around 3 or 4 bar, and that's the E61 pre-infusion chamber doing its job.
> 
> Pressure will go up to 10 bars, which is absolutely fine. This is controlled by the expansion valve.
> 
> You are focusing on pointless things, honestly. Focus on 18g in, 36g out, in 30 to 35 seconds. Get that right, and then worry about pressure and what nots. 😉
> 
> Also, I noticed you touching the group when the machine should be up to temperature and ready. How long are you warming the machine up from cold? You need around 35 minutes.
> 
> did you read the in depth review of this machine?


 Alright I see, I basically had it the wrong way round. Taste, Time and yield it's the main variable to focus on, not pressure and tamping.

I'll try again this afternoon and see if that makes a change.

I did read the review and watch David's videos many times before pulling the trigger on it.

Me touching the machine.... yes it was super hot. I'm a touchy person so I've burnt my fingers quite a few times already. It was nice and hot, well over 30 minutes of on time and not the first coffee of the day. It's on a smart plug that wakes up at 7.

Thanks for the tips, will report back on the results


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## skylark

Looks just like mine, there's nothing wrong there other than you need to grind a but finer which will slow up the shot abd pressure will remain a bit higher for a bit longer Other than that, no probs.


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## Santanor

Rob1 said:


> The pressure will drop a little as the puck erodes which is normal. If you are getting much above 9 bar then you should alter the OPV. I think on my machine it's set to 10 bar with a blind filter. Tamp pressure is probably not relevant and don't worry about metrics like time and pressure too much so long as they're ballpark e.g 25-45 seconds 6-9 bar etc.
> 
> Don't half lift the lever as it doesn't do anything useful and potentially messes up the temp control in the HX. It isn't a "manual pre-infusion" position.
> 
> It's not possible to tel you whether your grind is too coarse or fine without tasting the result, so you have to decide yourself based on how the shot tastes if you want to go finer or coarser or increase or decrease yield.
> 
> Also don't leave the portafilter sitting out of the group as it should be the same temp as the group after pre-heating in there for about 45 minutes on a standard E61. Fill with coffee, tamp, put it back in and pull the shot, the quicker you are with this process the better.


 Thanks for the reply. 
Got it, no half way up lever, let the machine do its thing.

I don't usually leave the portafilter out, but I got distracted messing with the camera and all that.... :/


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## Mrboots2u

Santanor said:


> Alright I see, I basically had it the wrong way round. Taste, Time and yield it's the main variable to focus on, not pressure and tamping.
> 
> I'll try again this afternoon and see if that makes a change.
> 
> I did read the review and watch David's videos many times before pulling the trigger on it.
> 
> Me touching the machine.... yes it was super hot. I'm a touchy person so I've burnt my fingers quite a few times already. It was nice and hot, well over 30 minutes of on time and not the first coffee of the day. It's on a smart plug that wakes up at 7.
> 
> Thanks for the tips, will report back on the results


 Dose and Yield are the main variables that dictate strength and extraction of a coffee. Time is a variable to be noted not used to drive changes to shot.

Ultimately its corny but taste is what drives changes, not if a shot has taken 35 seconds instead of 30.

Too weak , change the ratio

Too strong, change the ratio

Looking to add more sweetness , change the grind and or the ratio..Etc etc


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## Mrboots2u

MediumRoastSteam said:


> You are using the right basket for 18g.
> 
> pressure is fine. You are grinding too coarse, the puck is offering less resistance as it gets extracted. You need to grind finer.
> 
> ignore the middle position in the lever. It does nothing on your machine. Start timing from the moment you move the lever from the lowest position (off, all the way down) to the brew position (on, all the way up). Don't park in the middle!
> 
> aim for 30-35 seconds, adjust by taste.


 But the gauge is the pressure from thepump, not the pressure at the puck ?


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## DavecUK

Mrboots2u said:


> But the gauge is the pressure from thepump, not the pressure at the puck ?


 With the lowish flow rate of the QuietX pump under pressure (and of course producing espresso)...it's essentially the same as the pressure equalises across the system....


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## MediumRoastSteam

Mrboots2u said:


> But the gauge is the pressure from thepump, not the pressure at the puck ?


 It's not the same as in a Rotary pump, where it's measured at the head of the pump. The MaraX has a vibe pump, and the gauge is mounted in the brew circuit (I don't know much about the technicalities, sorry).

For instance, on the Elizabeth (and on the MaraX pretty sure), if you just let water through the group without the PF engaged, the pressure is ZERO.

On my old Profitec 700 the pressure is measured at the head of the pump, so, if you just draw water without the PF engaged, the pump would go right up to 9 bar. It was the same with my Rocket Cellini Evo, also equipped with a Rotary pump.

Maybe @DavecUK can chime in.

edit: Looks like Dave and I posted at pretty much at the same time.


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## DavecUK

With a high flow rotary passing water through a 0.5 or 0.7 mm gicleur (E61 group jet), then you can get a high positive pressure *with no portafilter installed*. Often this flow rate is so high that the pump reaches 9 bar (or whatever it's set) to and the bypass opens.

However, once you put coffee in the portafilter and are down to a flow rate of espresso....the pressure measured at any point in the brew system including above the coffee puck is the same. However, I love E61 mounted portafilters because they are not subject to pulsation effects, are very easy to change, and less connections onto the boiler. It's why I positively encourage manufacturers to use them.

In some reviews I may have simplified explanations for an audience very new to that type of machine as I usually assume zero knowledge.

I guess one day all machines with have displays and use a small pressure transducer to display pressure....I think it will become like car windows, where the manual ones are actually more expensive than the electric ones (if they even do manual wind any more). Already for steam pressure, we talk more and more about degrees C and less about pressure....increasingly machines display temperature only. Another welcome simplification.

P.S. It also means you can choose any gauge and not worry about front panel cutout dimensions.


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## Santanor

Right!

8 shots later I'm here to report on the progress.

Initial setup: 18g in 36 out in 22-ish seconds. Grind setting around the 25 mark from the factory calibration.

Final setup: 18g in 36 out in 37 seconds. much lighter tamp and Grind setting just over the 21 mark.

So I was able to go a bit finer and I think it tasted better. Not much difference but we're here to split hairs and geek out about espresso, right? 

I burned my tongue with the last espresso which I made into an americano so I'll have to wait a few hours to get my taste buds back....


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## DavecUK

Now there's temperature and ratio to play with. Your in the right ballpark grind wise with time and dose at 1:2

Try setting 0 and setting 1 for temp behind the drip tray, give it 20m to definitely reach the new temp. Also start tweaking the ratio. I like 18 in 36 out, but you might prefer 18 in 40g out or 32g out. I use different ratios/dose for different coffees quite often.


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## skylark

DavecUK said:


> Now there's temperature and ratio to play with. Your in the right ballpark grind wise with time and dose at 1:2
> 
> Try setting 0 and setting 1 for temp behind the drip tray, give it 20m to definitely reach the new temp. Also start tweaking the ratio. I like 18 in 36 out, but you might prefer 18 in 40g out or 32g out. I use different ratios/dose for different coffees quite often.


 So, once in the 1:2 grind 'window' the grind staysthe same? Is that what's being said here, its only the extraction dose/time which is being manipulated? Or are we going round in circles again with a finer grind to reach a longer time/extraction weight?


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## DavecUK

Yes, cut out one of the variables for now...grind.

Lets say your getting 18g in and 36g out in 27 seconds...

try 35g, out, 34, 33, 32 etc..and also go the other way at 37,38,40 etc.. See what the effect is.

Also try for 18g in and 36g out , varying the temp, High, Med and Low, again see what the effect is.

Then put the two together that you preferred most....is it still better......

If it is, look at the shot time/temp parameter and decide whether you want to tweak the grind. If the shots a tad quick (below 25), tighten it up a little, if it's a longish time (above 35, loosen the grind...see the effect.


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## MediumRoastSteam

skylark said:


> So, once in the 1:2 grind 'window' the grind staysthe same? Is that what's being said here, its only the extraction dose/time which is being manipulated? Or are we going round in circles again with a finer grind to reach a longer time/extraction weight?


 Once you get in that ball park, then you are "dialled in". You can then. For the sake of all discussions thus far, let's stick to a 1:2 ratio (18g in, 36g out).

if you want to increase the time, grind finer.
if you want to decrease the time, grind coarser.

Edit: remember, taste is subjective. Find out what works for you. Experiment, try, take notes. But change one variable at a time.


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## Santanor

This is so useful guys, thanks a lot for the tips!

I've been doing some testing and I think I've gone so fine that I got severe channeling. The shots were sour and "watery". Going a bit coarser restored the body of the shots


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## Sebinho9

Santanor said:


> (Sorry for the horrible Spanish accent)


 I am reviewing all things MaraX at the moment and this thread was helpful. But I mainly came here to say your accent isn't so strong. You're getting a Hector Bellerin-esque English twang!

I did Spanish at uni and wish my spanish accent were as good as your English one.


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## Santanor

Sebinho9 said:


> I am reviewing all things MaraX at the moment and this thread was helpful. But I mainly came here to say your accent isn't so strong. You're getting a Hector Bellerin-esque English twang!
> 
> I did Spanish at uni and wish my spanish accent were as good as your English one.


 Oh thanks a lot! Appreciate the comment


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