Ventilated Portafilter Project

la marzocco, synesso, simonelli, cimbali etc

Ventilated Portafilter Project

Postby Phil Proteau on Wed Dec 17, 2008 8:10 pm

Check out the video:

http://www.archive.org/details/Portafil ... ionProject


Here is an excerpt from a thread on the Counter Culture boardroom forum from David Lamont:

"SO, here’s the bottom line; the fact that the portafilter's only opening to the outside world is the hole at the bottom keeps the espresso from flowing out of the portafilter completely as it is extracted--it creates a vacuum..."




Basically the experiment in the video is a straight up comparison of shots through a stock LM portafilter and the modified Faema. There are certain things that became evident during the experiment and will be obvious by watching the video. There is one thing that you can't see in the video that is very important. The position of the holes in this Faema portafilter are not the best. While they function as predicted most of the time, they do become partially obscured by the over-hang of the bottom edge of the grouphead. There were a few shots were they became clogged or blocked, and they subsequently had none of the desired effect. I did not include these shots in the video. The most practical position for the holes is just behind the ear flanges. The holes will not be blocked if they come to rest at a position that is aligned with the slot intended for the ear flange insertion.

What you will notice is:

1- As soon as the flow of crema is full enough reach the top of the exit chute, the air in the peripheral portafilter chamber begins to oscillate in and out because of the air tight seal (in effect, respirating). This is the gurgle effect.

2- Fresher espresso that is gaseous will gurgle a lot, and a ventilated portafilter virtually eliminates the churning of the stream of coffee caused by the respiration of the portafilter.

3- The effect is much more subtle, if noticeable at all, in well aged espresso that has become very stable. I suspect that the ventilation holes in the last shot in the video my have clogged, as you can see a couple of gulps in the stream.


The benefit is that a good Barista can read information from the stream that indicates the quality of the extraction. It is a lot like reading the quality of extraction by watching a bottomless portafilter, only it is reading in a different language. Striping, blonding, curling of stripes, homogeneous creama color, bubble texture, flow rate etc... these things indicate something about the extraction. If this information is obscured by the gurgle effect, where the air is repeatedly sucked into and spit out of the exit chute, the Barista is receiving less feedback than they could be getting from a ventilated portafilter.

I don't think that ventilating the portafilter makes the coffee taste better. It does allow the Barista to monitor the quality a little more efficiently. They have the opportunity to toss out a questionable shot, increasing their percentage of good shots served.
Phil Proteau
 
Posts: 24
Joined: Fri Feb 29, 2008 9:49 am
Location: West Chester, Pa
full name: Phil Proteau
company: Counter Culture Coffee
: www.counterculturecoffee.com
: www.onionbean.wordpress.com

Re: Ventilated Portafilter Project

Postby Deferio on Thu Dec 18, 2008 6:01 am

Hey...clever!

But those same terms of stripping, blonding, homogeneous crema etc also apply to bottomless portafilters. Not really that much of a language translation there.

It seems to me that a good barista should be able to tell if the shot is bad or in need of attention after the first few seconds. Although there are always things that go wrong mid way or at the end. This seems to make viewing more consistent...it doesn't change the color of the shot but it sure seems to tone it down in it's tendency to be aggressive of gloop.
Neat idea.
Now if you just widened the exist holes...

-cd
Chris Deferio

Shop Operations
Sunergos Coffee
Louisville, KY
Deferio
 
Posts: 281
Joined: Sun Jul 03, 2005 11:44 am
Location: Louisville, KY
full name: Chris Deferio
company: Sunergos Coffee
: www.Sunergoscoffee.com
: www.defurious.wordpress.com

Re: Ventilated Portafilter Project

Postby terry on Sat Dec 20, 2008 10:12 am

Vented portafilters have been in use for many years. The vents are typically cut at the top of the portafilter, where the filter meets the edge, and looks like a notch.

The best vented portafilter of course is the bottomless.

Cool video.
Terry Z
Espressoparts.com
Olympiacoffee.com
terry
 
Posts: 211
Joined: Fri Jun 24, 2005 3:35 pm
Location: olympia, wa

Re: Ventilated Portafilter Project

Postby Deferio on Sat Dec 20, 2008 10:22 am

terry wrote:The best vented portafilter of course is the bottomless.


nice
Chris Deferio

Shop Operations
Sunergos Coffee
Louisville, KY
Deferio
 
Posts: 281
Joined: Sun Jul 03, 2005 11:44 am
Location: Louisville, KY
full name: Chris Deferio
company: Sunergos Coffee
: www.Sunergoscoffee.com
: www.defurious.wordpress.com


Who is online

Users browsing this forum: No registered users and 3 guests