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Date: 02 Oct 2006 22:27:36
From: Natalie Drest
Subject: Naked portafilters- less thermal mass?
I guess 'thermal' doesn't really need to be in the subject, because mass is
mass is mass... but you know what I mean.

I recently came across a photo of an Olympia Cremina owner proudly showing
how thick the piece of brass was that he had to remove to convert (read:
butcher) the portafilter to a naked one. Which got me to thinking.
I can see the benefits of a naked portafilter for perfecting packing,
tamping etc., but surely all that brass is there for a reason- namely
thermal stability.
Anybody done any tests on how much diffference it makes? Does a naked PF
make a worse shot than one with its pants on?


--
"I won't go into binary counting here. For further information you can
search the Internet, or cut off all but one of your fingers."
-Roger Nichols






 
Date:
From:
Subject:


 
Date: 05 Oct 2006 17:36:23
From: daveb
Subject: Re: Naked portafilters- less thermal mass?
And IF you do not do it JUST right -- You've got one hell of a mess!

as bnb said -- oh joy!

dave
notbob wrote:
> On 2006-10-05, Walter Voigt <wvoigt@comcast.net> wrote:
> > I haven't seen a "naked portafilter", but if it's just one without a
> > bottom, how would you prevent the emerging coffee stream from splattering
> > all in and around the cup?
>
> Ideally, if your tamp is good, the espresso will emerge and drool to
> the center of the basket and pour down in a single centralized stream.
> If it does, this means you grind is good, your coffee hasn't clumped,
> your tamp is tremendous, and you sphincter is clenched just right. If
> not, you're screwed, and not worthy to utter the sacred word "godshot"
> and other coffee nonsense. And it only costs $70+ to find out. Joy!
>
> pics of perfect pantyless pull:
>
> http://www.flickr.com/photos/tonx/9187898/in/set-10459/
>
> nb



 
Date: 05 Oct 2006 12:52:10
From: Walter Voigt
Subject: Re: Naked portafilters- less thermal mass?
I haven't seen a "naked portafilter", but if it's just one without a
bottom, how would you prevent the emerging coffee stream from splattering
all in and around the cup?
Walter.

"Natalie Drest" <mccoey06HAT@tpgCOAT.com.au > wrote in message
news:452105ae$1@dnews.tpgi.com.au...
> I guess 'thermal' doesn't really need to be in the subject, because mass
is
> mass is mass... but you know what I mean.
>
> I recently came across a photo of an Olympia Cremina owner proudly showing
> how thick the piece of brass was that he had to remove to convert (read:
> butcher) the portafilter to a naked one. Which got me to thinking.
> I can see the benefits of a naked portafilter for perfecting packing,
> tamping etc., but surely all that brass is there for a reason- namely
> thermal stability.
> Anybody done any tests on how much diffference it makes? Does a naked PF
> make a worse shot than one with its pants on?
>
>
> --
> "I won't go into binary counting here. For further information you can
> search the Internet, or cut off all but one of your fingers."
> -Roger Nichols
>
>




  
Date: 06 Oct 2006 10:50:45
From: Casey Lewis
Subject: Re: Naked portafilters- less thermal mass?
I think you'll find it's due to the surface tension of the water (coffee).
For the same reason a liquid in a tube will create a meniscus (climb up the
walls and create a convex shape) the coffee leaving the holes of the
portafilter will 'hang on to' the filter until the weight of coffee causes a
stream (solid or drops, depending on the flow rate) to drop into the
cup/glass. There are some great examples of this on youtube.
www.home-barista.com has the direct links if you wish.

If you look closely, liquids move in pretty funky ways! (ok....so there's
not much on tv where I am - haha).

Casey


"Walter Voigt" <wvoigt@comcast.net > wrote in message
news:t72dnRa2fsGhpbjYnZ2dnUVZ_uWdnZ2d@comcast.com...
>I haven't seen a "naked portafilter", but if it's just one without a
> bottom, how would you prevent the emerging coffee stream from splattering
> all in and around the cup?
> Walter.
>
> "Natalie Drest" <mccoey06HAT@tpgCOAT.com.au> wrote in message
> news:452105ae$1@dnews.tpgi.com.au...
>> I guess 'thermal' doesn't really need to be in the subject, because mass
> is
>> mass is mass... but you know what I mean.
>>
>> I recently came across a photo of an Olympia Cremina owner proudly
>> showing
>> how thick the piece of brass was that he had to remove to convert (read:
>> butcher) the portafilter to a naked one. Which got me to thinking.
>> I can see the benefits of a naked portafilter for perfecting packing,
>> tamping etc., but surely all that brass is there for a reason- namely
>> thermal stability.
>> Anybody done any tests on how much diffference it makes? Does a naked PF
>> make a worse shot than one with its pants on?
>>
>>
>> --
>> "I won't go into binary counting here. For further information you can
>> search the Internet, or cut off all but one of your fingers."
>> -Roger Nichols
>>
>>
>
>




  
Date: 05 Oct 2006 18:36:31
From: Danny
Subject: Re: Naked portafilters- less thermal mass?
Walter Voigt wrote:
> I haven't seen a "naked portafilter", but if it's just one without a
> bottom, how would you prevent the emerging coffee stream from splattering
> all in and around the cup?
> Walter.

It's a good test of your pack and tamp routine, see:

<http://www.danny.mcnulty.btinternet.co.uk/bottom.html >


--
Regards, Danny

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



   
Date: 06 Oct 2006 00:10:21
From: Craig Andrews
Subject: Re: Naked portafilters- less thermal mass?

"Danny" <danny@nospam.gaggia-espresso.com > wrote in message
news:4oku44Fcb0vfU1@individual.net...
> Walter Voigt wrote:
>> I haven't seen a "naked portafilter", but if it's just one without a
>> bottom, how would you prevent the emerging coffee stream from
>> splattering
>> all in and around the cup?
>> Walter.
>
> It's a good test of your pack and tamp routine, see:
>
> <http://www.danny.mcnulty.btinternet.co.uk/bottom.html>
>
>
> --
> Regards, Danny
>
> http://www.gaggia-espresso.com (a purely hobby site)
> http://www.malabargold.co.uk (UK/EU ordering for Malabar Gold blend)
>

Pure magic Danny, awesomely beautiful!! {;-D
Cheers,
Craig.



    
Date: 06 Oct 2006 10:39:46
From: Danny
Subject: Re: Naked portafilters- less thermal mass?
Craig Andrews wrote:

> Pure magic Danny, awesomely beautiful!! {;-D
> Cheers,
> Craig.

Thanks, Craig. I have an A4 enlargement I printed off which makes a
lovely photograph. Only 5MP camera though...


--
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 Oct 2006 16:10:06
From: Walter Voigt
Subject: Re: Naked portafilters- less thermal mass?
Hi Danny:

Thanks for you amazing pics of espresso coming out of a bottomless filter.
No wonder someone said: " a picture is worth a thousand words"! Nowhere has
this aphorism is been truer than in this case.
If you don't mind, one more question: have you observed if the pump
pressure, i.e., 15, 20 psi, has any effect on the symmetrical gathering of
the coffee in the center of the portafilter?
Thank you,
Regards,
Walter




    
Date: 06 Oct 2006 10:37:23
From: Danny
Subject: Re: Naked portafilters- less thermal mass?
Walter Voigt wrote:
> Hi Danny:
>
> Thanks for you amazing pics of espresso coming out of a bottomless filter.
> No wonder someone said: " a picture is worth a thousand words"! Nowhere has
> this aphorism is been truer than in this case.
> If you don't mind, one more question: have you observed if the pump
> pressure, i.e., 15, 20 psi, has any effect on the symmetrical gathering of
> the coffee in the center of the portafilter?
> Thank you,
> Regards,
> Walter
>
>

No pump - they are commercial spring lever machines, but others with
pump machines observe the same output. I think it really is down to
pack and tamp, since I can easily mess up and produce a spraying
pattern instead...

--
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 Oct 2006 12:12:28
From: notbob
Subject: Re: Naked portafilters- less thermal mass?
On 2006-10-05, Walter Voigt <wvoigt@comcast.net > wrote:
> I haven't seen a "naked portafilter", but if it's just one without a
> bottom, how would you prevent the emerging coffee stream from splattering
> all in and around the cup?

Ideally, if your tamp is good, the espresso will emerge and drool to
the center of the basket and pour down in a single centralized stream.
If it does, this means you grind is good, your coffee hasn't clumped,
your tamp is tremendous, and you sphincter is clenched just right. If
not, you're screwed, and not worthy to utter the sacred word "godshot"
and other coffee nonsense. And it only costs $70+ to find out. Joy!

pics of perfect pantyless pull:

http://www.flickr.com/photos/tonx/9187898/in/set-10459/

nb





 
Date: 02 Oct 2006 07:44:44
From: gscace
Subject: Re: Naked portafilters- less thermal mass?
All that hot brass does nice job of keeping the coffee hot as it leaves
the brew basket and travels down the spouts. Of course, if the brass
is cold, then it'll do a mighty fine job of cooling the coffee as well.
In the bottomless pf case you might ask yourself what will cool the
coffee if it just falls out of the brew basket and into the cup? Also,
what will contaminate the coffee with residue left over from all of the
shots brewed since the portafilter last got cleaned?

There's a lot of thermal mass in the body of the pf, as you state. But
I don't think it does a whole lot. The heat transfer path for
conduction heat transfer to the coffee is mainly through the rather
thin stainless steel basket, by way of the contact surface between the
group gasket and the brew basket. that's a pretty crappy flow path for
heat conduction and it's the same for both the bottomless and reggler
pfs. Convection and radiation heat exchange exists between the pf
floor and the bottom of the brew basket in the regular pf case, but not
in the case of the bottomless pf. I don't think this difference
amounts to much, considering the short time the coffee is in the brew
basket and the crappy heat transfer paths from the brass to the brew
basket and then from the basket to the coffee.

Barry Jarrett did some measurements of dry coffee grinds temperature
after the pfs were re-inserted into the machine. It took a pretty long
time for the coffee temperature to get over 100 deg. F - over a minute
as I recall. So if your practice is to insert the pf into the machine
and immediately hit the brew switch, then there is not gonna be much
difference at all - particularly when compared to the temperature ramp
that is introduced when hot water hits the cake.

-Greg



Natalie Drest wrote:
> I guess 'thermal' doesn't really need to be in the subject, because mass is
> mass is mass... but you know what I mean.
>
> I recently came across a photo of an Olympia Cremina owner proudly showing
> how thick the piece of brass was that he had to remove to convert (read:
> butcher) the portafilter to a naked one. Which got me to thinking.
> I can see the benefits of a naked portafilter for perfecting packing,
> tamping etc., but surely all that brass is there for a reason- namely
> thermal stability.
> Anybody done any tests on how much diffference it makes? Does a naked PF
> make a worse shot than one with its pants on?
>
>
> --
> "I won't go into binary counting here. For further information you can
> search the Internet, or cut off all but one of your fingers."
> -Roger Nichols