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Author Topic: Bezzera Strega Modifications Help  (Read 12780 times)

PeteC68

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Bezzera Strega Modifications Help
« on: 12/04/2014, 10:55 AM »
Hello All,

I have been thinking about making some modifications to my Strega. Don't get me wrong, I have been very happy with her but am interested in expanding the possibilities.

Would like your thoughts on the following and also any advice on who I could get to do the mods. I don't think I have the skill sets required to do the work to ensure it is done correctly.

Mod 1. Install a rotary dimmer switch on the vibe pump. This would allow greater control of pre-infusion settings and the variation would mean the machine could be used as: a traditional lever, pump extraction only or as designed.

Mod 2. Install a pressure gauge to measure pre-infusion pressure.

Mod 3. Install a PID controller for the group head heating elements.

Looking forward to your thoughts and finding who could do the work in Brisbane, QLD, AUS.

Many thanks, Pete



Koffee Kosmo

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« Reply #1 on: 12/04/2014, 11:38 AM »
Item (1) -  I am fairly sure that this can be done if the the right dial dimmer switch can be found that matches and marries well with the electrics used on the machine
Note - The vibe pump is also used to fill the boiler

Item (2) This can be done but at a high cost - the only correct way to do it is to have a gauge fitted on the cylinder
As a side note - The Bezzera Strega pre infusion is set to replicate house water pressure of approx 3 bar so you won't have much scope to adjust

Item (3) This is probably the easiest mod - as Bezzera have already done it with the BZ07 model
I am confident the Original part / PID unit can be fitted and adapted to the head heaters

KK
Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

conikal

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Bezzera Strega Modifications Help
« Reply #2 on: 12/04/2014, 02:10 PM »
 Im sure a PID can be adapted to control the group cartridge heaters,...... but im not sure the BZ 07 is much of a guide to use as its PID only controls the boiler so you would need to find a suitable sensor (and location on the group) as well as a mounting location for the PID read out.
 In fact,  depending on space available inside the Strega shell, an external mounted PID may be a better option.

Brett H

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Bezzera Strega Modifications Help
« Reply #3 on: 12/04/2014, 02:16 PM »
I am loving this thread already!  I was set to buy a Strega but for the lack of a PID.  I use mine frequently on my machine.  I reckon if they fitted one in the factory you'd have a game changer and a category killer on your hands!!  It'd go straight to my pool room that's for sure!
Diadema Junior Extra PID, La Pavoni Professional, Compak K10 Conical, Compak A8 Automatica, Fiorenzato F5, Rancilio Rocky, Behmor 1600, BBQ Roaster (retired), KKTO

Koffee Kosmo

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Bezzera Strega Modifications Help
« Reply #4 on: 12/04/2014, 03:55 PM »
Im sure a PID can be adapted to control the group cartridge heaters,...... but im not sure the BZ 07 is much of a guide to use as its PID only controls the boiler so you would need to find a suitable sensor (and location on the group) as well as a mounting location for the PID read out.
 In fact,  depending on space available inside the Strega shell, an external mounted PID may be a better option.

I am loving this thread already!  I was set to buy a Strega but for the lack of a PID.  I use mine frequently on my machine.  I reckon if they fitted one in the factory you'd have a game changer and a category killer on your hands!!  It'd go straight to my pool room that's for sure!

If the Bezzera PID needs to be fitted externally a small box or mounting plate can easily be made to accommodate it

[attach=1]

Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

C-man

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Bezzera Strega Modifications Help
« Reply #5 on: 12/04/2014, 05:22 PM »
I have fitted both dimmer and  pressure gauge to a  different machine, an old cheap sunbeam before
but the principle is the  same I am going to set it back up on my S24 someday.

finding the right rotary dimmer is the problem and  there is  no way  of  knowing which one.

I went threw a few until  I got one to work, and it still only worked at about 50% (careful as some even hold a charge, I got shocked pretty hard and  the  machine was UNPLUGGED)
then after a few months if burned it's self in and worked well after that. Mounting them needs to be  considered too.

The bar gauge was just basic plumbing and I could rev it up and down with the rotary dimmer to control the pressure and flow
but it was just line pressure same as the OPV does just variable.
Rancillio S24  HG one bench grinder Rosco mini- Hand grinder,  Presso,  modded popper

lukemc

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Bezzera Strega Modifications Help
« Reply #6 on: 12/04/2014, 08:50 PM »
Watching with interest. I have no idea how to install these mods but would happily pay someone who did!!
Alex Duetto II, Compak K3, Rocky Doserless, Gaggia Classic w/PID - Backup/Holiday machine

conikal

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Koffee Kosmo

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Bezzera Strega Modifications Help
« Reply #8 on: 13/04/2014, 05:42 PM »
Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

Lacehim

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Bezzera Strega Modifications Help
« Reply #9 on: 13/04/2014, 06:18 PM »
Pete,

They are some extreme mods your talking about, warranty voiding too.  Do you really need to see a gauge go up as a shot is pulled?

My personal opinion is that you should leave it alone, enjoy the coffee and not worry about the numbers, just enjoy what's in the cup.  If you really want all these things I would suggest another machine, without a lever.  Levers are simple things, if you want to control pressure profiles, you'll have to buy top end.

Mods for the sake of mods just isn't worth it for a few coffees a day.  PIDs are also over hyped IMO, they only control the temperature in a finer band, and it isn't going to be earth shattering adjustment wise when you take into account the amount of brass in the group on a lever.

Koffee Kosmo

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Bezzera Strega Modifications Help
« Reply #10 on: 13/04/2014, 06:34 PM »
Pete,

They are some extreme mods your talking about, warranty voiding too.  Do you really need to see a gauge go up as a shot is pulled?

My personal opinion is that you should leave it alone, enjoy the coffee and not worry about the numbers, just enjoy what's in the cup.  If you really want all these things I would suggest another machine, without a lever.  Levers are simple things, if you want to control pressure profiles, you'll have to buy top end.

Mods for the sake of mods just isn't worth it for a few coffees a day.  PIDs are also over hyped IMO, they only control the temperature in a finer band, and it isn't going to be earth shattering adjustment wise when you take into account the amount of brass in the group on a lever.

I haven't made a single mod on my Strega
It was a short learning period at the beginning but since then it's all been instinct and or let the machine do it's job

KK
Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

lukemc

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Bezzera Strega Modifications Help
« Reply #11 on: 13/04/2014, 06:36 PM »
I was super interested in the dimmer switch mod but maybe I should leave well enough alone!! The link to the mod to stop the valve venting internally is interesting....   KK have you had a look inside yours to see if it is corroding at all? I've only had mine a month or two so haven't had it open yet
Alex Duetto II, Compak K3, Rocky Doserless, Gaggia Classic w/PID - Backup/Holiday machine

Koffee Kosmo

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Bezzera Strega Modifications Help
« Reply #12 on: 13/04/2014, 06:52 PM »
I was super interested in the dimmer switch mod but maybe I should leave well enough alone!! The link to the mod to stop the valve venting internally is interesting....   KK have you had a look inside yours to see if it is corroding at all? I've only had mine a month or two so haven't had it open yet

Last time I took the lid off was almost a year ago - so I will have a look again and report back

KK
Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

Lacehim

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Bezzera Strega Modifications Help
« Reply #13 on: 13/04/2014, 07:27 PM »
KK have you had a look inside yours to see if it is corroding at all?

Your boiler is brass or copper so will not corrode from a few splashes of water on heat up.  If your frame gets splashed and it's not stainless steel when you might get some corrosion over a long period of time.  A small cup under the anti-vac works.  A friend suggested the foil out of a tealight which worked or me.

Or you can put one of these on http://www.jetblackespresso.com.au/shop/p/anti-vacuum-valve-1-4-hose-holder/ as per the HB thread.  That would also work. :)  I'm not sure what type of antivac you guys have in the Strega though so that might not fit straight on.

conikal

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Bezzera Strega Modifications Help
« Reply #14 on: 14/04/2014, 09:38 AM »
Pete,

They are some extreme mods your talking about, warranty voiding too.  Do you really need to see a gauge go up as a shot is pulled?

 I suspect that anyone contemplating mods like this would be sufficiently skilled to undertake any repairs or maintenance that may be required... Or  if they were prepared to pay for the mods to be done, they would probably also be prepared to suffer the costs of lost warranty cover.
 Some folks want more than just the result in the cup, they want to understand what influences that taste and how to change it, how to "control" it....just like some folk simply listen to music whilst others like to spend thousands on vinyl turntables, different amps, speakers, etc etc....Its a tech' thing. !
  FYI.. i have seen a barista in a commercial cafe sorting and  selecting specific individual beans for a single brew...just because he wanted a different result in the cup ! ::)
 Each to their own  !

PeteC68

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Bezzera Strega Modifications Help
« Reply #15 on: 14/04/2014, 10:03 PM »
Hello All,

Seems I have kicked a hornets nest here. Not my intention to stir things quite so much.

The pre-infusion pressure may begin quite low 2-3 bar but very rapidly increases to what the pump is capable of. At least 9 bar but some have reported the pump is factory set at 11 bar in some cases.

I was thinking that for versatility and small outlay (in comparison to an additional machine purchase) that the mods would give me what essentially would be a traditional commercial lever and the flexibility to change how pre-infusion affects the puck and hence the extraction results.

The gauge would be a real time display of pre-infusion pressure whether being left on one setting throughout the extraction or as an indicator of changing pressure using the dimmer switch during extraction pre-infusion.

I am not that concerned with the pressure during the spring phase; as I said, I am interested mainly in pre-infusion at this stage. As the water flow system is essentially an 'open' system from the check valve to the group head, a gauge could be connected in the system before the check valve.

As to warranty, given my machine is about 2 years old, it would be out of warranty coverage.

Anyway, glad this has gotten people thinking about things and possibilities. I would be still interested if someone knows either an individual or service company in Brisbane that could do the work for me.

Again thanks for your time and I respect your opinions on the matter.

Kind regards, Pete

Lacehim

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Bezzera Strega Modifications Help
« Reply #16 on: 14/04/2014, 10:27 PM »
Mod away to your hearts content Pete, no hornets nest here! :)  I was merely wondering what your trying to achieve with the mods.  I have a modded machine, but it has been done to make the machine more userfriendly and more controllable (antivac and OPV) so the mods were for a reason.  Is there something you don't like about the Strega's shots or is this just modifying to seek something that you think might be better?

Anyway, try member QM0996, he likes playing with machines and might be able to help.  He's helped a number of Brissy members before.

Koffee Kosmo

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Bezzera Strega Modifications Help
« Reply #17 on: 14/04/2014, 10:31 PM »
If you live on the north side contact QM0996
I can assist in mechanical fitment but he is the electronics Guru

KK
Bezzera Strega Lever: Mazzer Robur conical grinder Pullman Barista Tamper Convex:  Designer of the KKTO Home Roaster:

Blog - http://koffeekosmo.blogspot.com

Brett H

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« Reply #18 on: 15/04/2014, 09:36 AM »
Yep, another endorsement for QM!  He's fixed a couple of my beasties for me and his workmanship is second to none!
Diadema Junior Extra PID, La Pavoni Professional, Compak K10 Conical, Compak A8 Automatica, Fiorenzato F5, Rancilio Rocky, Behmor 1600, BBQ Roaster (retired), KKTO

C-man

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Bezzera Strega Modifications Help
« Reply #19 on: 15/04/2014, 02:54 PM »
he dosn't like dimmers though
Rancillio S24  HG one bench grinder Rosco mini- Hand grinder,  Presso,  modded popper

PeteC68

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Bezzera Strega Modifications Help
« Reply #20 on: 24/04/2014, 01:05 PM »
Hi,

Sorry I have not been back on to this thread sooner, but my wife is unwell presently and time has gotten away from me.

Lacehim - the mods were more about extending the range of the machine. Having said that, you did ask if there was anything I didn't like about the shots I am getting. In actual fact I am having issues with the taste of espresso shots.

Would it be best to seek help with that issue on this thread or start a new one?

Kind regards,

Pete

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« Reply #21 on: 24/04/2014, 04:54 PM »
Start a new thread Pete, might be better, you can refer to this one and we can keep this one more to do with the modifications you are discussing! :)

Hope your wife feels better soon!

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Bezzera Strega Modifications Help
« Reply #22 on: 24/04/2014, 09:34 PM »

Lacehim - the mods were more about extending the range of the machine. Having said that, you did ask if there was anything I didn't like about the shots I am getting. In actual fact I am having issues with the taste of espresso shots.



Unlikely to be a machine related and perhaps it would be helpful to articulate what an "issue" is with the espresso taste, e.g is it sour, does it lack sweetness or balance, thin and watery, non-persistent crema ? etc.

Most espresso problems are related to the combination of beans (roast profile applied), grinder + shot dynamics and then likely the temperature of the machine not matched correctly to the type of bean/blend and/or age of the coffee - a skilled and experienced barista can generally "workaround" limitations by using grind, dose and extraction speed to compensate.

Is it sour - get the machine +++ hot
Not picking up fruit - maybe the extraction is too tight or dose too low


Brett H

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« Reply #23 on: 26/04/2014, 01:00 PM »
Unlikely to be a machine related and perhaps it would be helpful to articulate what an "issue" is with the espresso taste, e.g is it sour, does it lack sweetness or balance, thin and watery, non-persistent crema ? etc.

Most espresso problems are related to the combination of beans (roast profile applied), grinder + shot dynamics and then likely the temperature of the machine not matched correctly to the type of bean/blend and/or age of the coffee - a skilled and experienced barista can generally "workaround" limitations by using grind, dose and extraction speed to compensate.

Is it sour - get the machine +++ hot
Not picking up fruit - maybe the extraction is too tight or dose too low

Darn you MyCuppa talking sense and sharing information of the highest quality and calibur... I was hoping for some electronics and plumbing porn.  Of course Pete MyCuppa is spot on if it's taste you're looking to improve.  If it's a project you want however we're still waiting here with baited breath. 

I too hope your wife makes a speedy recovery mate!
Diadema Junior Extra PID, La Pavoni Professional, Compak K10 Conical, Compak A8 Automatica, Fiorenzato F5, Rancilio Rocky, Behmor 1600, BBQ Roaster (retired), KKTO

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