Stephen Sweeney's TPF - a Transparent PortaFilter

Frans Goddijn

Yes, I *think* the O ring widens under pressure and then slips to the outside of the TPF, still making a good seal but allowing the TPF to slip a notch lower in the naked PF

Frans Goddijn

Tije is making one more:

http://kostverlorenvaart.blogspot.nl/2014/07/transparent-portafilter-making-part-1.html

Reiss Gunson

thats a nice, & useful, blog post frans. i look forward to part II. r.

Frans Goddijn

http://dailycoffeenews.com/2014/07/15/lathe-baby-lathe-the-making-of-a-transparent-portafilter-part-1/

Frans Goddijn

http://kostverlorenvaart.blogspot.nl/2014/07/transparent-portafilter-making-part-2.html

[video width=425 height=344 type=youtube]27ICbvB1-2U

Frans Goddijn

Tije's new TPF works very well! I tried it on the Rocket today. Hopefully next week I will visit Tije's workshop again to turn a L1 portafilter into a wide 'naked' one so the TPF will fit in that one as well.

The first series of extractions seems to illustrate that on an E61 brew goup at least it pays off to tamp firmly.

[video width=425 height=344 type=vimeo]101731383

Frans Goddijn

This one mainly for fun, also trying out a new lens to film the transparent basket up close, and a new LED light to help get clear video shots.

I used Sugru, a clever colorful putty, to 'repair' the broken TPF and sure enough it popped open with a splash.

Still, I like the swelling of the puck at the end. Will try to get better footage of that with the new transparent device.

[video width=425 height=344 type=youtube]JqVY4t6PW48

Frans Goddijn

A new clip.

1) the "puck jump" observed in a much earlier session is gone. A tamper that fiste easier and a gentle tamp.

2) the Fellini move does not disrupt the puck, but with the extra pressure one needs to lock in the portafilter better than I did.

[video width=425 height=344 type=vimeo]102283269

Mark Pitchford

A light tamp, but what also seems interesting is the length of time 'full' pre-infusion takes!

Frans Goddijn

EDIT: I had read too quickly and assumed you meant the time it takes from first pull on the lever until the last drop falls from the brew group.

Reiss Gunson

frans i think mark was just saying he was surprised (as in, he found it informative) to see how long it took for pre-infusion to saturate the puck. i am fairly sure he was thanking you for your efforts

Frans Goddijn

Thanks, my eyes had dashed across the words too fast and I thought it was about the full pull-till-last-drop time.

Yes, I think the pre-infusion is nice to see happening.

The puck changes in behaviour in phases:

1) dry grinds tamped: a semi-hard vulnerable pack

2) pre-infusion: getting soaked, preferably gently

3) wet puck no pressure: a flexible lush body, particles floating around above it

4) pressure changes: puck compacts and expands but keeps a very good seal around and below! Also during Fellini

5) water level falls, pressure falls, puck dries and air bubble escape sometimes suggesting the puck was damaged but it is not damaged during the active flexible-body phase

Mark Pitchford

Reiss Gunson post=4596 wrote: frans i think mark was just saying he was surprised (as in, he found it informative) to see how long it took for pre-infusion to saturate the puck. i am fairly sure he was thanking you for your efforts

Sorry if I was not clear - Reiss hit it on the head!

I meant it was about 6-8 seconds before the puck was fully saturated... Very Interesting!

Frans Goddijn

Mr Elvis Hsiao from Taiwan is pushing on the cutting edge of this field:

http://kostverlorenvaart.blogspot.nl/2014/08/elvis-hsao-doing-heroic-work-on.html