HomeRoast Digest


Topic: backpressure/"false" crema (7 msgs / 169 lines)
1) From: Allon Stern
So, having read about back pressure devices on various home espresso  
machines which produce more crema, I decided to remove said device  
from the portafilter basket on my Krups Espresso Novo 2000.  It comes  
off for cleaning; I never really knew before what it was for - it was  
just part of the anatomy of the machine.
Well. The first shot came through in about 14 seconds. Much too fast.  
I guess the back pressure allows for a coarser grind, with the  
presumption that home consumers won't have decent grinders, I guess.  
The shot tasted extremely bitter; there was a decent amount of crema,  
but not as much as I had been getting before removing the back  
pressure device.
I dialed down the grinder a couple of notches. A bit too slow; after  
30 seconds I only had about 1oz; was aiming for 1.5oz. This shot was  
a bit smoother. Still not quite there.
Slightly lighter on the tamp (okay, I forgot to dial it up a notch,  
so I compensated)
1.5oz 30 seconds. there we go.
This is at a grind that would have stalled with the backpressure  
device in place.
Nice, but not perfection.
I don't expect to get $1000 or even $500 espresso machine results  
with my bargain setup, but I figure by removing the add-ons I can get  
truer-to-form espresso.
Any comments? Are these back pressure devices actually useful? I  
would think with a finer grind, I should be getting better  
extraction, and that's a good thing, right?
I used an espresso roast from a local roaster; my well-meaning  
sweetie had gotten me a gift certificate from them for xmas; I need  
to show her the SM gift certificate order form ;)  next order from SM  
will include some espresso monkey; I'll also be trying some SO shots,  
but hey, I just got back from a two-week break and need to get  
roasting again and allow enough time for the beans to rest.
Still have some more experimentation to do, but first I have to  
convert these shots into a software design description, and maybe  
port a boot loader.
Programmer: A biological machine designed to convert caffeine into code
-
allon

2) From: kevin creason
Allon-
I am also depressurizing my espresso portafilter. I posted about this and my
Capresso grinder settings recently and was hoping for some feedback, but
nothing just yet. I went through all my steps to attempt to have hot enough
water, etc.
Will say that with a depressurized portafilter it is easier to tell when you
didn't do something 'best'. And I believe as a result that I am pulling
shots of a much higher quality. But I do make mistakes and waste 14-20 gr of
coffee more often making a horrible shot as a result of bad grind or tamping
instead of the pressure piece correcting that for me and making an 'eh'
shot.
HTH,
Kevin
On Jan 8, 2008 1:16 PM, Allon Stern  wrote:
<Snip>
-- 
-Kevin
Admit your errors before someone else exaggerates them. - Andrew V. Mason

3) From: Brett Mason
I started with a Starbucks Barista machine - a Saeco OEMed machine.
RIpped out the guts of the portafilter, did what you guys are doing.
It helped.  Never got the temperature right - look up temp surfing,
that will help too...
Eventually replaced the machine.  I have had a Silvia, Unic DIva,
Hamilton Beach cheapie, and now a new Oscra.  Finally something does
well all the time....
Do what you can.
Save every penny you can.
Put it in a can.
Don't go to dinner - put the money in a can.
Eat KRaft Mac-n-cheese - put the money in a can.
Soon you can - buy something to replace the can...
  Brett
On 1/8/08, kevin creason  wrote:
<Snip>
-- 
Cheers,
Bretthttp://homeroast.freeservers.com

4) From: raymanowen
On my Capresso Luxe, I removed the back pressure Dildo to turn it into a
naked PF. As I removed it, there was very little diaphragm pressure against
the orifices.
Now that I just measured the orifice diameters
On Jan 8, 2008 12:16 PM, Allon Stern  wrote:
<Snip>
-- 
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty
Wichita (ex- NYC Paramount) WurliTzer- 1976

5) From: raymanowen
??? Don't push buttons with your unused pinkies, Ray!
I hate that.
As I was saying- On my Capresso Luxe, I removed the back pressure Dildo to
turn it into a naked PF. As I removed it, there was very little diaphragm
pressure against the orifices.
Now that I just measured the twin orifice diameters and think a little, the
pencil says the diaphragm pressure would only need to be around 2.5 pounds
against the orifices to create a liquid back pressure of 150 psi.
Without additional restriction caused by excessive tamping and packing to
create a very dense Puck, that 150psi would exist throughout the puck- an
advantage of the post puck dildo. I put it back and still tamp.
I pre-infuse until I see the first drop of crema, and stop for 3 - 5 sec.
But that reverses the "espresso" phenomenon, doesn't it? Don't tell me- it
tastes great!
Cheers, Mabuhay -RayO, aka Opa!
On Jan 8, 2008 5:05 PM,  wrote:
<Snip>
-- 
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty
Wichita (ex- NYC Paramount) WurliTzer- 1976

6) From: Leo Zick
i cut the PF on my old krups when i used it.
didnt make a diff, but it was fun to watch :)
On Jan 8, 2008 2:16 PM, Allon Stern  wrote:
<Snip>

7) From: Barry Dryden
FWIW,  I bought a non-pressurized portafilter for my Saeco Classico
and really found no
difference between it and the original in the crema.   Most important
is grinding properly and checking the timing of your shots.  Buying a
Mazzer Super Jolly was the best improvement I've made. YMMV
BarryD


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