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JKK

Expobar Brewtus Variable Pump Pressure Mod

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Hello

 

All this talk of pressure profiling and flow vs pressure.

 

I thought I should try out a presure/flow control

on the humble VBE pump.

 

I am using a cheap ([email protected]) variac voltage control

in series of the live wire on the pump.image.jpg

 

Picture shows bare unit, but I have put the

PCB into a waterproof ABS box.

 

 

DANGER NOTE:

THIS MOD INCOLVES MAINS VOLTAGE,

SHOULD ONLY BE CARRIED OUT BY EXPERIENCED

ELECTRICIAN.

 

 

Results: ( using EK43 )

 

Suprisingly effective, gives a much more rounded and three

dimensional taste to the espresso.

Before I was having problems with too much brightness

in the flavours.

 

Runs at about 18sec on 0-4bar, then I turn up the

dial for 8bar, then slowly back down to 4bar.

 

Pressure was measured off the Brewtus gauge.

 

It is perhaps not true pressure profiling, maybe

flow profiling, someone more scientific might

like to chime in . . .

Edited by JKK
spelling !

__________________________________________/////EK43////EXP DB/////

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Good work.

 

i'm looking to drop the flow. But this was interesting.


Ghe sboro fioi!

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Nice one. I'd be interested in playing with this mod as well as I also find that my Brewtus shots can be on the acidic side if I'm not careful. At the mo I've got my opv limited to 7bar with a blind basket and tend to downdose by about a gram to get a bit extra headspace for a longer ramp up. I'll be fitting a new 0.5mm gicleur tonight if it arrives today in order to reduce flow some more.


Instagram = @unolonu

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Thanks.

 

Today I tried comparing the pressure profile mentioned

earlier vs a flat 5bar ( that MrBoots discussed in the other expo thread ).

 

The flow pressure flat profile was better than 8 or 9 bar flat

much less sharp and more chocolate.

But the ramped profile had a better balance of fruit flavours

to chocolate flavours.

 

Test beans:

Workshop Cult of Done

 

18.5g > 40g IMS 18 basket


__________________________________________/////EK43////EXP DB/////

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Hello JKK,

 

great project! It's very motivating to read that you achieved positive results wrt. flavor.

Have you also modified or do you plan to modify the group in order to disable preinfusion?

 

Best regards,

holgr

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Hi

sorry for late reply, just noticed your question.

 

No, I did look at the idea of disabling it, as featured in the

Rocket 60V, but plumbing is not one of my skills unfortunately.


__________________________________________/////EK43////EXP DB/////

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I wonder if the variac can be connected up to a microprocessor (like a raspberry pi or arduino) to allow it to be controlled automatically over time? Must be possible right? Might need a manual 'Go' switch to make it simpler.

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Hi

sorry for late reply, just noticed your question.

 

No, I did look at the idea of disabling it, as featured in the

Rocket 60V, but plumbing is not one of my skills unfortunately.

 

Hi,

sorry now for my late reply.

 

Could you please tell me more about the Rocket 60V? I wasn't aware of the fact that they also disabled preinfusion with that machine.

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I wonder if the variac can be connected up to a microprocessor (like a raspberry pi or arduino) to allow it to be controlled automatically over time? Must be possible right? Might need a manual 'Go' switch to make it simpler.

 

Hi ZappyAd,

 

the simplemost solution to that could be to use the Kemo power control unit (Link).

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Hi,

sorry now for my late reply.

 

Could you please tell me more about the Rocket 60V? I wasn't aware of the fact that they also disabled preinfusion with that machine.

 

I'm no expert, but it's their variable pressure machine like the Vesuvius.

But the I read somewhere that the rocket uses a stock E61 head, so they disable the preinfusion on it.


__________________________________________/////EK43////EXP DB/////

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