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Date: 02 Jul 2006 22:59:41
From: Don Task
Subject: Reneka Techno - Water Debit Modification
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Basically this question is targeted at David Lewis based on his post of
Feb 2005 where he stated:
"I've inserted a needle valve in my Techno, between the output of the
pump and the input of the flow meter. I did this to adjust the water
debit down to the recommended 90 ml/10 seconds." ---end quote---
I believe Rene also made this modification to one of his Technos.
Anyway, I was following all the Techno mod flow rate posts with much
interest back in 2005 and had planned on making the modification as
well...then life got in the way and I more or less dropped off
alt.coffee. Now, a year and a half later, I finally have some time to
play with teh Techno. FYI: Still pulling a minimum of four doubles
every day. Still love it.
For those not familiar with the Techno, the debit is not regulated by
means of water- restriction by a gicleur but rather by a timer. By
design the water debit is around 200ml in 10 seconds as opposed to what
many believe is the optimum of 90ml in 10sec.
My Techno is long out of warranty ... and I'm getting tinker fever.
Several who have made the mod have commented they notice an improvement
in flavor so I'd like to do some experiments of my own.
David, I see you're still very active here in AC (thankfully)... if you
still have access to the information, could you identify what needle
valve you installed, part number if available, and where you purchased
it from. (or maybe a web link?)
I see in another thread you identified it needs to be installed as
close as possible to the flow meter. Did you ever take any pics of the
mod when you did it? Does your Techno still emit the occasional screech
when reducing the debit to 90ml/10s?
Thanks,
Don Task
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Date: 03 Jul 2006 08:30:44
From: DavidMLewis
Subject: Re: Reneka Techno - Water Debit Modification
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Don Task wrote:
> "I've inserted a needle valve in my Techno, between the output of the
> pump and the input of the flow meter. I did this to adjust the water
> debit down to the recommended 90 ml/10 seconds." ---end quote---
>
> My Techno is long out of warranty ... and I'm getting tinker fever.
> Several who have made the mod have commented they notice an improvement
> in flavor so I'd like to do some experiments of my own.
>
> David, I see you're still very active here in AC (thankfully)... if you
> still have access to the information, could you identify what needle
> valve you installed, part number if available, and where you purchased
> it from. (or maybe a web link?)
McMaster-Carr, part number 7822K21. I used that one because the metric
instant tube fittings that had a high-enough recommended temperature
and pressure were BSPT.
>
> I see in another thread you identified it needs to be installed as
> close as possible to the flow meter. Did you ever take any pics of the
> mod when you did it? Does your Techno still emit the occasional screech
> when reducing the debit to 90ml/10s?
>
I didn't take pictures, at least that I can remember. I'd say the pump
makes a noise about every tenth time. I do also have to say that I took
the modification out because I was house-swapping for six months, and
because I wanted to be able to make cafe crema. My impression is that
once my distribution technique had sufficiently improved due to a year
with a bottomless portafilter, it made much less difference. If you do,
you also have to rig something up that allows you to measure the
pressure at actual brewing flow rates (not the 90 ml/10 s, but the
roughtly 10 ml/10 s that you get while pulling a shot), because there's
a significant pressure drop across the needle valve.
Best,
David
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Date: 03 Jul 2006 12:46:22
From: Don Task
Subject: Re: Reneka Techno - Water Debit Modification
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DavidMLewis wrote:
> McMaster-Carr, part number 7822K21. I used that one because the metric
> instant tube fittings that had a high-enough recommended temperature
> and pressure were BSPT.
>I do also have to say that I took
> the modification out because I was house-swapping for six months, and
> because I wanted to be able to make cafe crema. My impression is that
> once my distribution technique had sufficiently improved due to a year
> with a bottomless portafilter, it made much less difference. If you do,
> you also have to rig something up that allows you to measure the
> pressure at actual brewing flow rates (not the 90 ml/10 s, but the
> roughtly 10 ml/10 s that you get while pulling a shot), because there's
> a significant pressure drop across the needle valve.
Hi David,
Thanks for the quick response and information. Yep, in following your
earlier post I was aware of the need to also measure brewing pressure.
That said... you mentioned you removed the modification. Reading
between the lines... I wasn't sure if I should assume you have since
put it back in, or decided against it due to improvements on technique
and the bottomless PF.
Like others, I'm always trying to improve my shots and have always
pondered the large water debit of the Techno. It seems you always lead
the pack on Techno mods and upgrades so I'm more than comfortable with
your findings.
I guess the net of my interest (question) is ... knowing what you know
now... is it safe to say you wouldn't do it again. I should probably
revise my earlier statement when I said I would like to do my own
experiments. If the modification has negligible effect it sounds like
it might be more trouble than it's worth.
Believe it or not I have yet to hack the bottom off one of my PF's.
After reading all the post I had decided to make that mod as well but
have held off hoping to stumble upon a spare or replacement PF that
will fit my Techno. Looks like I may have to bite the bullet and buy a
new one.
Don
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Date: 04 Jul 2006 06:44:24
From: David Lewis
Subject: Re: Reneka Techno - Water Debit Modification
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On 2006-07-03 20:46:22 +0100, "Don Task" <s_presso@hot-shot.com > said:
> I guess the net of my interest (question) is ... knowing what you know
> now... is it safe to say you wouldn't do it again. I should probably
> revise my earlier statement when I said I would like to do my own
> experiments. If the modification has negligible effect it sounds like
> it might be more trouble than it's worth.
The difference, given decent distribution technique, is small. I
thought about hacking in a bypass so the restriction was only in for
the single-shot and double-shot buttons, but never did it. I'm
returning home soon, and I don't know whether I'll put it back.
>
> Believe it or not I have yet to hack the bottom off one of my PF's.
> After reading all the post I had decided to make that mod as well but
> have held off hoping to stumble upon a spare or replacement PF that
> will fit my Techno. Looks like I may have to bite the bullet and buy a
> new one.
Hi,
I had Terry Z modify one of mine. If you want to do cafe crema, you
need an unmodified one because a bottomless portafilter will spray
everywhere with that much flow. By the way, a 5/8" piece of nice
hardwood makes a perfect tamping stand for a bottomless Techno
portafilter.
Best,
David
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Date: 08 Jul 2006 16:15:32
From: René van Sint Annaland
Subject: Re: Reneka Techno - Water Debit Modification
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In article <1151955982.326175.193030@h44g2000cwa.googlegroups.com >, s_presso@hot-shot.com
says...
>
> Hi David,
> Thanks for the quick response and information. Yep, in following your
> earlier post I was aware of the need to also measure brewing pressure.
> That said... you mentioned you removed the modification. Reading
> between the lines... I wasn't sure if I should assume you have since
> put it back in, or decided against it due to improvements on technique
> and the bottomless PF.
>
> Like others, I'm always trying to improve my shots and have always
> pondered the large water debit of the Techno. It seems you always lead
> the pack on Techno mods and upgrades so I'm more than comfortable with
> your findings.
>
> I guess the net of my interest (question) is ... knowing what you know
> now... is it safe to say you wouldn't do it again. I should probably
> revise my earlier statement when I said I would like to do my own
> experiments. If the modification has negligible effect it sounds like
> it might be more trouble than it's worth.
Adding a needle valve to a Techno is a metter of a few minutes work, so it's no trouble
really. A lower flow rate allows me to grind finer and I find that it does make a difference
in the cup, but we are talking about a personal preference here. I don't care much for a
cafe suisse for example, so that may have something to do with whether or not you'd prefer
gradual pre-infusion over electronic pre-infusion (or both at the same time of course).
>
> Believe it or not I have yet to hack the bottom off one of my PF's.
> After reading all the post I had decided to make that mod as well but
> have held off hoping to stumble upon a spare or replacement PF that
> will fit my Techno. Looks like I may have to bite the bullet and buy a
> new one.
Whatever you do, Don, I think a bottomless portafilter is worth having!
--
René van Sint Annaland
www.justespresso.com
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Date: 01 Aug 2006 17:54:50
From: DavidMLewis
Subject: Re: Reneka Techno - Water Debit Modification
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Ren=E9 van Sint Annaland wrote:
> I would suggest looking at the difference between the pressure measured a=
t the group with a
> "blind filter" portafilter gauge and the internal gauge you are going to =
fit and then apply
> this difference when pulling a shot at 10ml/10 secs. Not quite scientifi=
c, but it saves
> having to get another gizmo/rig.....
> >
Ren=E9, your trying to _avoid_ getting another tool is the surest sign
that you're _not_ American!
Best,
David
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Date: 03 Aug 2006 14:53:44
From: René van Sint Annaland
Subject: Re: Reneka Techno - Water Debit Modification
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In article <1154480090.471323.101050@m73g2000cwd.googlegroups.com >, DavidMLewis@mac.com
says...
> > >
> Ren=E9, your trying to _avoid_ getting another tool is the surest sign
> that you're _not_ American!
>
Coming from an American....now how do I take this? But anyway, I am pleased to be what I am
(not that I have a lot of choice in the matter!), kinda Dutch New Zealander I suppose....
--
René van Sint Annaland
www.justespresso.com
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Date: 01 Aug 2006 12:38:53
From: Don Task
Subject: Re: Reneka Techno - Water Debit Modification
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> >Don Task wrote:
> > David, I see you're still very active here in AC (thankfully)... if you
> > still have access to the information, could you identify what needle
> > valve you installed, part number if available, and where you purchased
> > it from. (or maybe a web link?)
>
> DavidMLewis wrote:
> McMaster-Carr, part number 7822K21. I used that one because the metric
> instant tube fittings that had a high-enough recommended temperature
> and pressure were BSPT.
Sorry David, nothing like a question on an old thread! :-(
I decided to go ahead with the mod. I'm on a business trip with some
free time so I figured I'd order the control valve and instant fittings
from McMaster-Carr. I was assuming the instant on fittings would be a
no brainer. My error!. I'm on a trip and won't be home for two weeks so
I have no way to measure the diameter of the tubing where I'll be
inserting the valve and I certainly don't want to guess. Is there any
chance you could also provide me with the McMaster part number of the
instant-on fittings you used?
Also, in the past, for adjusting pump pressure, I've been using a
modified blind PF that has a instant-on fitting mounted on the bottom.
>From the PF instant-on fitting a tube exits one of the spouts and
connects to a pressure gauge. I was thinking of adding a T-Fitting an
installing the gauge internally (like the newer Technos). With all your
experimentation experience, where would you suggest I insert the T
fitting for the pressure gauge? (Assuming I'm also installing the flow
control valve)
> you also have to rig something up that allows you to measure the
> pressure at actual brewing flow rates (not the 90 ml/10 s, but the
> roughtly 10 ml/10 s that you get while pulling a shot), because there's
> a significant pressure drop across the needle valve.
Without giving away any trade secrets... what type of "rig" did you use
to measure the 10 ml/10s?
Thanks
Don
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Date: 02 Aug 2006 12:32:35
From: René van Sint Annaland
Subject: Re: Reneka Techno - Water Debit Modification
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In article <1154461133.923154.52050@h48g2000cwc.googlegroups.com >, s_presso@hot-shot.com
says...
> Sorry David, nothing like a question on an old thread! :-(
>
> I decided to go ahead with the mod. I'm on a business trip with some
> free time so I figured I'd order the control valve and instant fittings
> from McMaster-Carr. I was assuming the instant on fittings would be a
> no brainer. My error!. I'm on a trip and won't be home for two weeks so
> I have no way to measure the diameter of the tubing where I'll be
> inserting the valve and I certainly don't want to guess. Is there any
> chance you could also provide me with the McMaster part number of the
> instant-on fittings you used?
Not David, but I know he used the adapters 5449K176.
>
> Also, in the past, for adjusting pump pressure, I've been using a
> modified blind PF that has a instant-on fitting mounted on the bottom.
> >From the PF instant-on fitting a tube exits one of the spouts and
> connects to a pressure gauge. I was thinking of adding a T-Fitting an
> installing the gauge internally (like the newer Technos). With all your
> experimentation experience, where would you suggest I insert the T
> fitting for the pressure gauge? (Assuming I'm also installing the flow
> control valve)
Currently the T-fitting is mounted on the pump exit.
>
> > you also have to rig something up that allows you to measure the
> > pressure at actual brewing flow rates (not the 90 ml/10 s, but the
> > roughtly 10 ml/10 s that you get while pulling a shot), because there's
> > a significant pressure drop across the needle valve.
>
> Without giving away any trade secrets... what type of "rig" did you use
> to measure the 10 ml/10s?
> Thanks
> Don
I would suggest looking at the difference between the pressure measured at the group with a
"blind filter" portafilter gauge and the internal gauge you are going to fit and then apply
this difference when pulling a shot at 10ml/10 secs. Not quite scientific, but it saves
having to get another gizmo/rig.....
>
>
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Date: 02 Aug 2006 15:26:42
From: Don Task
Subject: Re: Reneka Techno - Water Debit Modification
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Ren=E9 van Sint Annaland wrote:
> In article <1154461133.923154.52050@h48g2000cwc.googlegroups.com>, s_pres=
so@hot-shot.com
> says...
> > inserting the valve and I certainly don't want to guess. Is there any
> > chance you could also provide me with the McMaster part number of the
> > instant-on fittings you used?
>
> Not David, but I know he used the adapters 5449K176.
Thanks Ren=E9... I was guessing the tube O.D would be between 6 and
10mm. Sure glad I asked. I'm surprised it came in a 6mm... (being at
the small end of my educated guess).
> >
> > Also, in the past, for adjusting pump pressure, I've been using a
> > modified blind PF that has a instant-on fitting mounted on the bottom.
> > >From the PF instant-on fitting a tube exits one of the spouts and
> > connects to a pressure gauge. I was thinking of adding a T-Fitting an
> > installing the gauge internally (like the newer Technos). With all your
> > experimentation experience, where would you suggest I insert the T
> > fitting for the pressure gauge? (Assuming I'm also installing the flow
> > control valve)
>
> Currently the T-fitting is mounted on the pump exit.
Since I can't refer to my machine... is the T-fitting actually on the
pump assembly at the exit, or is it an inline T fitting on the
discharge line? If its physically on the pump body, is it a threaded
fitting? Sorry for the detailed questions but since I'm getting ready
to place an order with McMaster-Carr I'd like to get everything I need
in one shot. Until I read your reply, I was planning on using the gauge
from my blind PF with an inline T-fitting. However it sounds like I'll
still need it to measure 10ml/10 sec. McMaster-Carr has some pressure
gauges but I'm thinking I might find a better match via EPNW or another
espresso parts dealer. That said, If you or anyone has found an
acceptable aftermarket modification for installing an internal pressure
gauge ( i.e., and has a list of all the required part numbers) I'd
certainly appreciate it. I've also considered cutting the front panel
and installing the gauge for external viewing but will need to take a
second look to see how much room I have behind the panel.
> >
> > Without giving away any trade secrets... what type of "rig" did you use
> > to measure the 10 ml/10s?
>
> I would suggest looking at the difference between the pressure measured at
> the group with a "blind > filter" portafilter gauge and the internal gaug=
e you
> are going to fit and then apply this difference when > pulling a shot at
> 10ml/10 secs. Not quite scientific, but it saves having to get another g=
izmo/rig.....
Sorry, I'm missing something here. My thought is, by comparing the
difference between the two gauges it would only give me the pressure
drop across the needle valve. I'm not sure how that would help me in
regulating the 10ml/10 secs. What am I missing? Initially I was
thinking I could simply adjust the flow to deliver the required 10ml/10
secs but understand that may be tough while trying to maintain 8-9 bars
brewing pressure. Is that the issue?
Considering these factors, does the installation of the flow control
valve inhibit the electronic pre-infusion in anyway?
On the subject of pre-infusion, has anyone experimented with adjusting
the preinfusion pressure? (Not sure if its possible) The idea behind
preinfusion is to saturate the puck before hitting it with the
pressurized water. On the Techno, pre-infusion pressure and the
pressurized water of the shot are the same. I always felt the full
pressure pre-infusion cycle had the potential to blast a hole thru the
puck before the shot was pulled. I'd like to experiment with dropping
the infusion pressure as well as extending the time between the end of
the pre-infusion cycle when the shot begins. Schomer (Schomer who?)
believes the standard is one to three seconds. My Techno only pauses
for one second... I'd be curious to see how extenting the saturation
time might change the cup.=20
Thanks
Don Task
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Date: 03 Aug 2006 14:40:59
From: René van Sint Annaland
Subject: Re: Reneka Techno - Water Debit Modification
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In article <1154557602.178614.29430@i42g2000cwa.googlegroups.com >, s_presso@hot-shot.com
says...
>
> Since I can't refer to my machine... is the T-fitting actually on the
> pump assembly at the exit, or is it an inline T fitting on the
> discharge line? If its physically on the pump body, is it a threaded
> fitting? Sorry for the detailed questions but since I'm getting ready
> to place an order with McMaster-Carr I'd like to get everything I need
> in one shot. Until I read your reply, I was planning on using the gauge
> from my blind PF with an inline T-fitting. However it sounds like I'll
> still need it to measure 10ml/10 sec. McMaster-Carr has some pressure
> gauges but I'm thinking I might find a better match via EPNW or another
> espresso parts dealer. That said, If you or anyone has found an
> acceptable aftermarket modification for installing an internal pressure
> gauge ( i.e., and has a list of all the required part numbers) I'd
> certainly appreciate it. I've also considered cutting the front panel
> and installing the gauge for external viewing but will need to take a
> second look to see how much room I have behind the panel.
From memory, the T-fitting is threaded and is on the pump assembly. One or two people just
ordered the parts from Reneka (via me of course). I remember it was a little bit tricky,
over the years fittings on machines have changed somewhat, but in the end we got there. I
would need to hunt through my old files to get all the part numbers, but it could be done.
Not if you are in a hurry, though, summer holidays are upon us (well, not us, but in France
for sure - Reneka will be closed most of this month :-(
> > >
> > > Without giving away any trade secrets... what type of "rig" did you use
> > > to measure the 10 ml/10s?
> >
> > I would suggest looking at the difference between the pressure measured at
> > the group with a "blind > filter" portafilter gauge and the internal gaug=
> e you
> > are going to fit and then apply this difference when > pulling a shot at
> > 10ml/10 secs. Not quite scientific, but it saves having to get another g=
> izmo/rig.....
>
> Sorry, I'm missing something here. My thought is, by comparing the
> difference between the two gauges it would only give me the pressure
> drop across the needle valve. I'm not sure how that would help me in
> regulating the 10ml/10 secs.
Do I understand you correctly that you want to control your flow rate by means of setting the
pump pressure (or needle valve?), rather than by resistance in the portafilter basket?
What am I missing? Initially I was
> thinking I could simply adjust the flow to deliver the required 10ml/10
> secs but understand that may be tough while trying to maintain 8-9 bars
> brewing pressure. Is that the issue?
If you were to set the needle valve at 10mls/10 secs, I think it would be tough to get 9 bar
at the group if that is what you mean. But why would you want to set the needle valve to 10
mls/ 10 secs in the first place?
I am sure you are way ahead of me here, so please help me out.
>
> Considering these factors, does the installation of the flow control
> valve inhibit the electronic pre-infusion in anyway?
Yes, it slows down incoming water for the pre-infusion, i.e less water.
>
> On the subject of pre-infusion, has anyone experimented with adjusting
> the preinfusion pressure? (Not sure if its possible) The idea behind
> preinfusion is to saturate the puck before hitting it with the
> pressurized water. On the Techno, pre-infusion pressure and the
> pressurized water of the shot are the same. I always felt the full
> pressure pre-infusion cycle had the potential to blast a hole thru the
> puck before the shot was pulled. I'd like to experiment with dropping
> the infusion pressure as well as extending the time between the end of
> the pre-infusion cycle when the shot begins. Schomer (Schomer who?)
> believes the standard is one to three seconds. My Techno only pauses
> for one second... I'd be curious to see how extenting the saturation
> time might change the cup.=20
>Yes, Schomer was essentially talking about gradual infusion. The Techno however has a high
water debit, so pre-infusion can only be short, it should not apply full pressure at the puck
at that stage. With just gradual infusion (so not the programmed electronic pre-infusion),
the pour looks very much like machinery with gradual infusion, be it a Giotto or a Marzocco
machine. The interesting part is to figure out whether or not the combination of the two
pre-infusions make for a better cup. I have tried it, but there isn't much in it. The main
difference is in reducing the water debit and I don't think all Techno customers who have
tried agreed on the benefits of reducing flow rate either, so nothing new there.
I, however, prefer the slower flow rate for my blend of coffee. However, this makes
preparing a cafe suiise much harder if not impossible on the machine, but I don't drink that
anyway.
>
>
--
René van Sint Annaland
www.justespresso.com
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