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Date: 05 Jan 2007 08:01:06
From: Bob Wilson
Subject: preinfusion - no longer popular?
My old Capresso 101 had a three phase, timed shot pump. There was a
short, 3-4 second, preinfusion, a 3-4 second pause, and would then press
out a shot. It eventually wore out and the replacement lacks this
feature.

I've tried making shots with and without the preinfusion and can't tell
that it makes a whole lot of difference. The only effect is if I have
the coffee a little to finely ground, preinfusion seems to help it
become a block and significantly slow down the subsequent shot.

Comments?

Bob Wilson




 
Date: 11 Jan 2007 18:35:37
From: Flasherly
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> stan.shire@gmail.com wrote:
>
> > Wouldn't a 1.1 bar (roughly atmospheric pressure) be equivalent to
> > using a small spray bottle to dampen the puck before putting it into
> > the group? Would this work? Would this help? I'm off to try it.
> > Stan "5 shots and counting" S
> >
>
> That's 1.1 bar above atmospheric pressure, or that's the way I
> understand espresso machine pressure gauges to work. IE: 2.1 bar in
> the boiler. (Or, open the steam valve to see what 1.1 bar is...) :)

Appears a function of temperature as well, e.g. if you measure your
wand temperature across steam output and it is precisely 100 degress
celsius, then absolute pressure exists at 1.01325 bar at 212
fahrenheit, which is all the boiler should be capable. But I've
measured running steam, closer to 225-230 fahrenheit, and that's with
the rotary pump running. Since my machine claims its good, say, for 9
or 12 bars and the prepared temperature on the extraction cycle for the
boiler is less than at steam, then the pump would seem to need continue
to build to a point to overcome the puck resistance, up to it's highest
utility, at closest to a density not to produce blocked stoppage at the
manufacturer's rathing. Grind fine and get your money's worth is best
I can figure.

http://www.engineeringtoolbox.com/saturated-steam-properties-d_101.html



 
Date: 10 Jan 2007 21:26:26
From:
Subject: Re: preinfusion - no longer popular?

> At the show in Charlotte we were using a 1mm gicleur with the profiling pump.
> With smaller gicleurs, as you say, we couldn't get control.
>
>
>
> --
>
>
> -Andy S.
>
> http://www.flickr.com/photos/andy_s/sets/

What size are you using on your current set up?



  
Date: 11 Jan 2007 19:30:36
From: Andy Schecter
Subject: Re: preinfusion - no longer popular?
jepy@mac.com wrote:
> What size are you using on your current set up?

Urp...don't know, I'm using needle valves, not gicleurs.


--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


 
Date: 10 Jan 2007 21:25:55
From:
Subject: Re: preinfusion - no longer popular?

> At the show in Charlotte we were using a 1mm gicleur with the profiling pump.
> With smaller gicleurs, as you say, we couldn't get control.
>
>
>
> --
>
>
> -Andy S.
>
> http://www.flickr.com/photos/andy_s/sets/

What size are you using on your current sert up?



 
Date: 10 Jan 2007 08:13:07
From:
Subject: Re: preinfusion - no longer popular?

Nick Cho wrote:
> Well, technically, I have three "variants" of pre-infusion available to
> me:
> - pump pulsing/fake preinfusion (which you can do on just about any
> machine as you know)
> - line-pressure preinfusion (5-bar line pressure, or full 9-bar
> pump-pressure, courtesy Synesso)
> - flow-restricted pressure ramp-up infusion (on our Lineas and our
> Synesso)
>
> I guess what I was sort of getting at is that pump-pulse pre-infusion,
> line-pressure preinfusion, in my estimation (FWIW) can yield
> improvements... but only with un-restricted flow machines.
>
> I believe that the flow-restricted ramp-up infusion on our machines
> renders pump-pulsing PI not only unnecessary, but ineffective. In
> other words, because of the restricted flow, the benefits of the
> pump-pulsed water infusion are hampered by the inability to apply full
> pressure fairly instantaneously.
>
> It wouldn't however, undermine the line-pressure PI... but I see no
> improvements there nonetheless (at least with the flow-restrictors
> there).

A long time ago I got rid of the .6's, way too retarded for any type of
control on pi. Just going to a .8 has allowed much more control of ramp
speed.



  
Date: 10 Jan 2007 23:11:46
From: Andy Schecter
Subject: Re: preinfusion - no longer popular?
kate.ermacoff@gmail.com wrote:
> A long time ago I got rid of the .6's, way too retarded for any type of
> control on pi. Just going to a .8 has allowed much more control of ramp
> speed.

Hi "kate." :-)

At the show in Charlotte we were using a 1mm gicleur with the profiling pump.
With smaller gicleurs, as you say, we couldn't get control.



--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


 
Date: 09 Jan 2007 05:47:49
From: Danny Joe
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> Danny Joe wrote:
>
> > acutally, i was trying to be funny.
> >
> > Someone wanted to spritz their coffee for the same effect. I was saying
> > that you need some pressure, so tamp it damp.
> >
> > Didn't mean to offend.
> >
> > d (tough life in the trenches today) j
> >
>
> Sorry, my understanding of "terse" is different to yours. I thought
> you were being serious and disputing preinfusion, apologies.
>
> --
> Regards, Danny
>
> http://www.gaggia-espresso.com (a purely hobby site)
> http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)

No worries.

I really just liked the rhyme - Tamp the Damp.

You will enthuse if you pre-infuse

You won't regret if the puck is wet

d (sorry for that) j



  
Date: 09 Jan 2007 14:58:03
From: Danny
Subject: Re: preinfusion - no longer popular?
Danny Joe wrote:

Suck that puck (and stand the muck), who gives a f*ck ;)

measure the pressure
as an eager beaver
on the lever might
When 'owt at the spout
Give it some clout
And watch the espresso pour right...


--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 08 Jan 2007 19:18:33
From: Nick Cho
Subject: Re: preinfusion - no longer popular?

jim schulman wrote:
>
> So real preinfusion (a slow pressure ramp up) works better than fake
> preinfusion -- pump pulsing?
>
> Pump pulsing was something the Krups of the world came up with
> (actually Capresso, iirc). Why LM added it as an option for the GS3 is
> a slight mystery. Probably, they were promising a paddle wheel group,
> realized it wouldn't do squat in the middle position when working off
> a tank, rather than the mains, and added the pump pulse as a gee whiz
> gimcrack. As yoiu say, the narower restrictors stock on the new groups
> is making the LMs less of a bear when it comes to packing them right.

Well, technically, I have three "variants" of pre-infusion available to
me:
- pump pulsing/fake preinfusion (which you can do on just about any
machine as you know)
- line-pressure preinfusion (5-bar line pressure, or full 9-bar
pump-pressure, courtesy Synesso)
- flow-restricted pressure ramp-up infusion (on our Lineas and our
Synesso)

I guess what I was sort of getting at is that pump-pulse pre-infusion,
line-pressure preinfusion, in my estimation (FWIW) can yield
improvements... but only with un-restricted flow machines.

I believe that the flow-restricted ramp-up infusion on our machines
renders pump-pulsing PI not only unnecessary, but ineffective. In
other words, because of the restricted flow, the benefits of the
pump-pulsed water infusion are hampered by the inability to apply full
pressure fairly instantaneously.

It wouldn't however, undermine the line-pressure PI... but I see no
improvements there nonetheless (at least with the flow-restrictors
there).



  
Date: 08 Jan 2007 22:38:53
From: jim schulman
Subject: Re: preinfusion - no longer popular?
On 8 Jan 2007 19:18:33 -0800, "Nick Cho" <portafilter@gmail.com >
wrote:

>It wouldn't however, undermine the line-pressure PI... but I see no
>improvements there nonetheless (at least with the flow-restrictors
>there).

My take is that if the puck is fully soaked and tight by the time the
pressure hits hard, there's nothing more to do. You can soak it either
with line pressure preinfuse or a small jet, no point doing both.

I'm wondering if the pump pulse thing (without a restirctor) soaks the
puck fully, and then waits long enough so any cracks it's made are
sealed by the puck expansion. Perhaps if it's set up to that it would
work just as well.


 
Date: 08 Jan 2007 17:04:40
From: Paul Pratt
Subject: Re: preinfusion - no longer popular?

jim schulman wrote:

> Pump pulsing was something the Krups of the world came up with
> (actually Capresso, iirc). Why LM added it as an option for the GS3 is
> a slight mystery. Probably, they were promising a paddle wheel group,
> realized it wouldn't do squat in the middle position when working off
> a tank, rather than the mains, and added the pump pulse as a gee whiz
> gimcrack. As yoiu say, the narower restrictors stock on the new groups
> is making the LMs less of a bear when it comes to packing them right.

Jim, off a bottle you will get a decent dribble as you are effectively
bleeding the boiler and you can get a fairly good cake soaking. You
certainly can't get 1st drops into the cup (which is what many people
aim for with PI ?) but you can prepare the coffee for the imminent
onslaught.

Paul



  
Date: 08 Jan 2007 19:06:48
From: jim schulman
Subject: Re: preinfusion - no longer popular?
On 8 Jan 2007 17:04:40 -0800, "Paul Pratt" <paul@just-java.com > wrote:

>Jim, off a bottle you will get a decent dribble as you are effectively
>bleeding the boiler and you can get a fairly good cake soaking.

I didn't know that; it must work differently for hionking big brew
boilers rather than small HXs


 
Date: 08 Jan 2007 15:24:58
From: Danny Joe
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> Danny Joe wrote:
snip
>
> No point in being terse unless you fully understand preinfusion and
> especially how it occurs on commercial lever machines (where it was
> actually invented in it's purest form). It's more than just your
> description might imply, and I've been serving espresso for five years
> from lever machines and can see the difference preinfusion makes, at
> least on these machines, where it was designed in. It acts as a
> visual clue as to the grind and pack, since drops appear at the spout
> at the appropriate time, and with the appropriate viscosity and speed
> when everything is right.
>
> --
> Regards, Danny
>
acutally, i was trying to be funny.

Someone wanted to spritz their coffee for the same effect. I was saying
that you need some pressure, so tamp it damp.

Didn't mean to offend.

d (tough life in the trenches today) j



  
Date: 09 Jan 2007 09:42:36
From: Danny
Subject: Re: preinfusion - no longer popular?
Danny Joe wrote:

> acutally, i was trying to be funny.
>
> Someone wanted to spritz their coffee for the same effect. I was saying
> that you need some pressure, so tamp it damp.
>
> Didn't mean to offend.
>
> d (tough life in the trenches today) j
>

Sorry, my understanding of "terse" is different to yours. I thought
you were being serious and disputing preinfusion, apologies.

--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 08 Jan 2007 11:14:05
From: Danny Joe
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> Danny Joe wrote:
>
> > Tamp a wet puck.
> >
>
> ?
>
> --
> Regards, Danny
>
> http://www.gaggia-espresso.com (a purely hobby site)
> http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)

Well, it was a little terse.

If you want to, you could dampen the coffee in the pf, then tamp (30lbs
is about 2 bar, right?)

I don't think it will work. but it is an idea.



  
Date: 08 Jan 2007 20:29:15
From: Danny
Subject: Re: preinfusion - no longer popular?
Danny Joe wrote:

> Well, it was a little terse.
>
> If you want to, you could dampen the coffee in the pf, then tamp (30lbs
> is about 2 bar, right?)
>
> I don't think it will work. but it is an idea.
>

No point in being terse unless you fully understand preinfusion and
especially how it occurs on commercial lever machines (where it was
actually invented in it's purest form). It's more than just your
description might imply, and I've been serving espresso for five years
from lever machines and can see the difference preinfusion makes, at
least on these machines, where it was designed in. It acts as a
visual clue as to the grind and pack, since drops appear at the spout
at the appropriate time, and with the appropriate viscosity and speed
when everything is right.

--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 08 Jan 2007 07:40:31
From: Danny Joe
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> stan.shire@gmail.com wrote:
>
> > Wouldn't a 1.1 bar (roughly atmospheric pressure) be equivalent to
> > using a small spray bottle to dampen the puck before putting it into
> > the group? Would this work? Would this help? I'm off to try it.
> > Stan "5 shots and counting" S
> >
>
> That's 1.1 bar above atmospheric pressure, or that's the way I
> understand espresso machine pressure gauges to work. IE: 2.1 bar in
> the boiler. (Or, open the steam valve to see what 1.1 bar is...) :)
>
>
> --
> Regards, Danny
>

Tamp a wet puck.



  
Date: 08 Jan 2007 16:10:38
From: Danny
Subject: Re: preinfusion - no longer popular?
Danny Joe wrote:

> Tamp a wet puck.
>

?

--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 07 Jan 2007 22:25:15
From: Nick Cho
Subject: Re: preinfusion - no longer popular?

jim schulman wrote:
> On Fri, 5 Jan 2007 08:01:06 -0600, bwilson4use@hotmail.com (Bob
> Wilson) wrote:
>
> >Comments?
>
> There's cycles like that built into lots of superautos and machines
> that work with restrictors. They help get some sort of extraction when
> the grind is off. With fresh and properly ground coffee, it makes no
> difference.
>
> Preinfusion on commercial machines remains controversial. It does help
> prevent channelled shots; but I'm beginning to think it may just
> compensate for less than perfect, or less than mild mannered,
> dispersion blocks and shower screens.
>
> Ken Fox and I were able to do a preinfuse versus not test on his
> Cimbali Juniors. The preinfuse made the machine much easier to use (I
> had problems with the non preinfuse version, being new to the machine,
> but none with the preinfuse one). The preinfused shots were slightly
> better overall, but probably this was a result of including less than
> perfect shots in the non group.

I confess little experience with home machines.

That said, I've tried and tried and tried to get pre-infusion to yield
improvements on both our Linea, and our Synesso. As far as I can see,
the fact that both machines have 0.6mm flow restrictors (a.k.a.
"gicleurs") seems to do two things: improve extraction overall (more
viscous, sweeter, more clarity in flavors), and screw up on-off-on
pre-infusion.

With the pressure ramp-up of a pump-driven machine like ours through
heavy flow restriction, it takes takes 5 seconds or so (off the top of
my head) to achieve full brew pressure at the puck. Then, you kick it
off, and the pressure's down to zero instantaneously. Then after
whatever predetermined or choreographed pause, it takes another 5
seconds or so to ramp up the pressure. This seems to undermine the
preinfusion process.

I could, I suppose, play with removing one of the flow-restrictors and
play with P.I. That said, I had a weird (at the time) conversation
with an espresso machine designer a little while ago: I asked him why
he put pre-infusion on his machine, and he said, "Well, because people
seem to want it." I asked him if in his R&D phase, if he ever found
benefits to preinfusion. He said no.

You want it? You got it!



  
Date: 08 Jan 2007 09:59:57
From: jim schulman
Subject: Re: preinfusion - no longer popular?
On 7 Jan 2007 22:25:15 -0800, "Nick Cho" <portafilter@gmail.com >
wrote:

>As far as I can see,
>the fact that both machines have 0.6mm flow restrictors (a.k.a.
>"gicleurs") seems to do two things: improve extraction overall (more
>viscous, sweeter, more clarity in flavors), and screw up on-off-on
>pre-infusion.

So real preinfusion (a slow pressure ramp up) works better than fake
preinfusion -- pump pulsing?

Pump pulsing was something the Krups of the world came up with
(actually Capresso, iirc). Why LM added it as an option for the GS3 is
a slight mystery. Probably, they were promising a paddle wheel group,
realized it wouldn't do squat in the middle position when working off
a tank, rather than the mains, and added the pump pulse as a gee whiz
gimcrack. As yoiu say, the narower restrictors stock on the new groups
is making the LMs less of a bear when it comes to packing them right.


   
Date: 08 Jan 2007 09:55:30
From: Ken Fox
Subject: Re: preinfusion - no longer popular?
"jim schulman" <jim_schulman@ameritech.net > wrote in message
news:pbq4q2hfon41mg4us76pr9v4bed7lp890l@4ax.com...
> On 7 Jan 2007 22:25:15 -0800, "Nick Cho" <portafilter@gmail.com>
> wrote:
>
>>As far as I can see,
>>the fact that both machines have 0.6mm flow restrictors (a.k.a.
>>"gicleurs") seems to do two things: improve extraction overall (more
>>viscous, sweeter, more clarity in flavors), and screw up on-off-on
>>pre-infusion.
>
> So real preinfusion (a slow pressure ramp up) works better than fake
> preinfusion -- pump pulsing?
>
> Pump pulsing was something the Krups of the world came up with
> (actually Capresso, iirc). Why LM added it as an option for the GS3 is
> a slight mystery. Probably, they were promising a paddle wheel group,
> realized it wouldn't do squat in the middle position when working off
> a tank, rather than the mains, and added the pump pulse as a gee whiz
> gimcrack. As yoiu say, the narower restrictors stock on the new groups
> is making the LMs less of a bear when it comes to packing them right.

From hands on comparison and testing that Jim S. and I did last year,
comparing my rotary machine with and without delay-timer-induced
preinfusion, to my vibe machine, the conclusions were pretty obvious. Full
bore 9 bar pressure with no time lag assaults the puck and results in a
higher percentage of sink shots than does a slow ramp up, as given either by
my rotary with preinfusion or the vibe in its native state.

In my opinion, the two conditions, slow ramp up from a vibe pump, or
preinfusion at reduced pressure for ~6 seconds then full bore 9 bar,
produces virtually indistinguishable results and a similar experience in the
hands of the barista.

ken




  
Date: 08 Jan 2007 00:11:49
From: Ken Fox
Subject: Re: preinfusion - no longer popular?
"Nick Cho" <portafilter@gmail.com > wrote in message
news:1168237514.884978.191060@11g2000cwr.googlegroups.com...
> >
> With the pressure ramp-up of a pump-driven machine like ours through
> heavy flow restriction, it takes takes 5 seconds or so (off the top of
> my head) to achieve full brew pressure at the puck.

you already have pre-infusion, or some varient of it




 
Date: 07 Jan 2007 13:08:27
From:
Subject: Re: preinfusion - no longer popular?

Heat + Beans wrote:
> I've been experimenting on my new LaSpaziale with pre-infusion. Hit
> the start, count one and two and. . . .Stop. count to 3, Start again,
> and let the machine do it's thing. Channeling has been cut to zero,
> including the micro-spritzies. Shots continue to be very good, but I
> can't comment on shot quality differences "caused" by pre-infusion
> ------ just that the pour looks better.
> tin
>
>
> jim schulman wrote:
> > On Fri, 5 Jan 2007 08:01:06 -0600, bwilson4use@hotmail.com (Bob
> > Wilson) wrote:
> >
> > >Comments?
> >
> > There's cycles like that built into lots of superautos and machines
> > that work with restrictors. They help get some sort of extraction when
> > the grind is off. With fresh and properly ground coffee, it makes no
> > difference.
> >
> > Preinfusion on commercial machines remains controversial. It does help
> > prevent channelled shots; but I'm beginning to think it may just
> > compensate for less than perfect, or less than mild mannered,
> > dispersion blocks and shower screens.
> >
> > Ken Fox and I were able to do a preinfuse versus not test on his
> > Cimbali Juniors. The preinfuse made the machine much easier to use (I
> > had problems with the non preinfuse version, being new to the machine,
> > but none with the preinfuse one). The preinfused shots were slightly
> > better overall, but probably this was a result of including less than
> > perfect shots in the non group.
I've been trying tin's technique. The shots don't seem to be
different but the pour is much prettier with virtually no channeling,
foam blowouts, etc.
This might be a case of "couldn't hurt."
Stan S



 
Date: 06 Jan 2007 16:59:13
From: Heat + Beans
Subject: Re: preinfusion - no longer popular?
I've been experimenting on my new LaSpaziale with pre-infusion. Hit
the start, count one and two and. . . .Stop. count to 3, Start again,
and let the machine do it's thing. Channeling has been cut to zero,
including the micro-spritzies. Shots continue to be very good, but I
can't comment on shot quality differences "caused" by pre-infusion
------ just that the pour looks better.
tin


jim schulman wrote:
> On Fri, 5 Jan 2007 08:01:06 -0600, bwilson4use@hotmail.com (Bob
> Wilson) wrote:
>
> >Comments?
>
> There's cycles like that built into lots of superautos and machines
> that work with restrictors. They help get some sort of extraction when
> the grind is off. With fresh and properly ground coffee, it makes no
> difference.
>
> Preinfusion on commercial machines remains controversial. It does help
> prevent channelled shots; but I'm beginning to think it may just
> compensate for less than perfect, or less than mild mannered,
> dispersion blocks and shower screens.
>
> Ken Fox and I were able to do a preinfuse versus not test on his
> Cimbali Juniors. The preinfuse made the machine much easier to use (I
> had problems with the non preinfuse version, being new to the machine,
> but none with the preinfuse one). The preinfused shots were slightly
> better overall, but probably this was a result of including less than
> perfect shots in the non group.



 
Date: 06 Jan 2007 10:28:16
From:
Subject: Re: preinfusion - no longer popular?

Danny wrote:
> Bob Wilson wrote:
> > My old Capresso 101 had a three phase, timed shot pump. There was a
> > short, 3-4 second, preinfusion, a 3-4 second pause, and would then press
> > out a shot. It eventually wore out and the replacement lacks this
> > feature.
> >
> > I've tried making shots with and without the preinfusion and can't tell
> > that it makes a whole lot of difference. The only effect is if I have
> > the coffee a little to finely ground, preinfusion seems to help it
> > become a block and significantly slow down the subsequent shot.
> >
> > Comments?
> >
> > Bob Wilson
>
> I think the problem with "modern" preifusion is the pump pressure.
> Lever machines (commercial spring levers) have an inbuilt preinfusion
> at boiler pressure (1.1 bar) rather than the 9 bar pump extraction
> pressure. This allows the puck to fairly gently get soaked, which I
> think helps. I certainly think that shots from my preinfused levers
> taste better, but since I don't have any non-preinfused lever machines
> I can't prove whether it's the lever or preinfusion that makes the
> shots better.
>
> --
> Regards, Danny
>
> http://www.gaggia-espresso.com (a purely hobby site)
> http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)
Wouldn't a 1.1 bar (roughly atmospheric pressure) be equivalent to
using a small spray bottle to dampen the puck before putting it into
the group? Would this work? Would this help? I'm off to try it.
Stan "5 shots and counting" S



  
Date: 06 Jan 2007 21:12:48
From: Danny
Subject: Re: preinfusion - no longer popular?
stan.shire@gmail.com wrote:

> Wouldn't a 1.1 bar (roughly atmospheric pressure) be equivalent to
> using a small spray bottle to dampen the puck before putting it into
> the group? Would this work? Would this help? I'm off to try it.
> Stan "5 shots and counting" S
>

That's 1.1 bar above atmospheric pressure, or that's the way I
understand espresso machine pressure gauges to work. IE: 2.1 bar in
the boiler. (Or, open the steam valve to see what 1.1 bar is...) :)


--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 05 Jan 2007 18:14:01
From: Danny
Subject: Re: preinfusion - no longer popular?
Bob Wilson wrote:
> My old Capresso 101 had a three phase, timed shot pump. There was a
> short, 3-4 second, preinfusion, a 3-4 second pause, and would then press
> out a shot. It eventually wore out and the replacement lacks this
> feature.
>
> I've tried making shots with and without the preinfusion and can't tell
> that it makes a whole lot of difference. The only effect is if I have
> the coffee a little to finely ground, preinfusion seems to help it
> become a block and significantly slow down the subsequent shot.
>
> Comments?
>
> Bob Wilson

I think the problem with "modern" preifusion is the pump pressure.
Lever machines (commercial spring levers) have an inbuilt preinfusion
at boiler pressure (1.1 bar) rather than the 9 bar pump extraction
pressure. This allows the puck to fairly gently get soaked, which I
think helps. I certainly think that shots from my preinfused levers
taste better, but since I don't have any non-preinfused lever machines
I can't prove whether it's the lever or preinfusion that makes the
shots better.

--
Regards, Danny

http://www.gaggia-espresso.com (a purely hobby site)
http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)



 
Date: 05 Jan 2007 10:17:53
From: jim schulman
Subject: Re: preinfusion - no longer popular?
On Fri, 5 Jan 2007 08:01:06 -0600, bwilson4use@hotmail.com (Bob
Wilson) wrote:

>Comments?

There's cycles like that built into lots of superautos and machines
that work with restrictors. They help get some sort of extraction when
the grind is off. With fresh and properly ground coffee, it makes no
difference.

Preinfusion on commercial machines remains controversial. It does help
prevent channelled shots; but I'm beginning to think it may just
compensate for less than perfect, or less than mild mannered,
dispersion blocks and shower screens.

Ken Fox and I were able to do a preinfuse versus not test on his
Cimbali Juniors. The preinfuse made the machine much easier to use (I
had problems with the non preinfuse version, being new to the machine,
but none with the preinfuse one). The preinfused shots were slightly
better overall, but probably this was a result of including less than
perfect shots in the non group.