Results 1 to 26 of 26
Like Tree6Likes
  • 2 Post By TC
  • 2 Post By Jonathon
  • 1 Post By Javaphile
  • 1 Post By Javaphile

Thread: Clear naked portafilter

  1. #1
    TC
    TC is offline
    .
    Join Date
    Oct 2004
    Location
    Melbourne
    Posts
    14,665

    Clear naked portafilter

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Nice shot from a very low dose....

    Last edited by Javaphile; 18th March 2019 at 03:03 PM. Reason: Fixed link
    Tony_Barista and Dragunov21 like this.

  2. #2
    Life-long Learner DesigningByCoffee's Avatar
    Join Date
    Aug 2008
    Location
    Millthorpe NSW
    Posts
    2,041
    Very cool
    And no tamp by the looks. We do stress over the minutae sometimes, don't we!

  3. #3
    Senior Member
    Join Date
    Dec 2010
    Posts
    395
    Not just a clear PF, a clear basket as well!

  4. #4
    Senior Member Journeyman's Avatar
    Join Date
    May 2009
    Location
    Bendigo
    Posts
    1,029
    There's a curious effect around 22 seconds where the grinds lift up before the water comes in. That looks like it would break apart any tamping done.

    Also it seems a long preinfusion time; that 1st basket sits for 16 secs in one shot then about another 12 in the 2nd shot - I don't know if he showed us repeat footage or not but even if so, 16 secs seems a long time and if not, that's about a 30 sec preinfusion time. Wouldn't that stuff the coffee taste?

  5. #5
    Senior Member
    Join Date
    Apr 2010
    Posts
    558
    Some very interesting background on this project, from HB, which confirms it's in slo-mo:

    It surprised me that so far there are just these two clips, but after corresponding with Stephen and getting the updates on his first TPF model and the next one, I got a better understanding of the problems that arise when building such a one-off tool.

    One needs to find a way to replace both the wall of the portafilter and the basket itself with something transparent, but it needs to hold the metal bottom of a normal filter basket. Also, the top should lock in securely to the brew group. Then, the combination of very different materials (metal, acrylic, sealant) must be able to all hold together in temperatures rising and falling very quickly from room temperature to temperatures close to the temperature of boiling water, and huge pressure differences from the pressure in the room (on the bottom) to 8 or 9 bar (at the top). Plus, a coffee puck tamped inside, air and water flowing around...

    I can now imagine how the Spaziale team would maybe have felt the urge to push further and use their TPF more, but it's possible that it didn't hold that long and the manager, looking at the cost in time and materials, likely veto'd any further exploits.

    Stephens final TPF held out during a few tests in his workshop and it stayed in one piece during fifteen tests Roemer Overdiep and I did in Amsterdam on the Londinium I lever machine, but then it too began to give. One side is starting to pop open and from what I heard from Stephen, you do not want to be standing very close, peering at the looking glass, when it pops open en explodes hot water and coffee grinds in your face.

    Before we started documenting these TPF experiments, we rented a Sony 4K High Speed camcorder. It fits the Canon prime lenses we have available so we would not miss any detail.

    We also learned something we would maybe not have found out without the TPF: when using a tamper that fits very tight, it's best to tamp lightly. After finishing a firm tamp and pulling back the tamper, the puck can be pulled loose along the sides and this results in the puck jumping up and being slammed down again when the spring lever is being pulled. In a pump machine the puck will not jump up of course, but the seal along the outside of the puck will allow some initial flow.

    The "puck jump" happens very fast but is very clearly seen when we use the super slow motion feature of the camera. It hardly causes a problem but to get a nice and even flow when using a very tight fitting tamper, tamping lightly seems advised.

    When we used the tamper that fits my millennium La Pavoni Europiccola, that proved a very nice fit for Stephens TPF and the puck remained still, allowing the raised piston to suck in air through the puck instead of along the sides. Sadly, by the time we figured that out, the life cycle of the TPF was nearing the end and we couldn't risk damaging the $10.000 camera...

    For a short moment (elongated in the footage) there's a lot more coffee flying around in the TPF than I imagined there would be, but very swiftly, once the pressure is applied, all clears up and you can see the tiniest stream of water along the grains of coffee grinds and air and CO2 struggling to get out of the way.

    We cannot thank Stephen Sweeney enough for making this little project possible!
    Journeyman and Mariner like this.

  6. #6
    Senior Member
    Join Date
    Mar 2012
    Posts
    1,275
    .??? Link...?

  7. #7
    Senior Member Yelta's Avatar
    Join Date
    Jun 2009
    Location
    Moonta SA.
    Posts
    7,029
    Quote Originally Posted by blend52 View Post
    .??? Link...?
    Try post 1 this thread.

  8. #8
    Senior Member
    Join Date
    Mar 2012
    Posts
    1,275
    Quote Originally Posted by Yelta View Post
    Try post 1 this thread.
    i did.....nothing there ???

    EDIT:
    OK, dumped the Ipad, and switched onto the old PC and now the Video shows.

    Note to self. Keep away from Apple products. They screw with your head !

  9. #9
    Junior Member
    Join Date
    Aug 2010
    Location
    Adelaide
    Posts
    14
    Same problem, link does not appear on ipad, here it is as a URL link instead of video......



    Alternatively it's vimeo.com/89652511

  10. #10
    Senior Member
    Join Date
    Dec 2010
    Location
    Toowoomba QLD
    Posts
    417
    Better off reading about it from its originator on HB.

  11. #11
    Senior Member
    Join Date
    Jan 2014
    Location
    Sweden/Germany
    Posts
    141

    Transparent Portafilter


  12. #12
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,376
    Pretty sure I've seen that here before. Even the second shot looked like a gusher to me...

  13. #13
    TC
    TC is offline
    .
    Join Date
    Oct 2004
    Location
    Melbourne
    Posts
    14,665

  14. #14
    Senior Member chokkidog's Avatar
    Join Date
    Apr 2008
    Location
    Victoria, Australia
    Posts
    2,095
    Quote Originally Posted by Jonathon View Post
    Some very interesting background on this project, from HB, which confirms it's in slo-mo:

    It surprised me that so far there are just these two clips, but after corresponding with Stephen and getting the updates on his first TPF model and the next one, I got a better understanding of the problems that arise when building such a one-off tool.

    One needs to find a way to replace both the wall of the portafilter and the basket itself with something transparent, but it needs to hold the metal bottom of a normal filter basket. Also, the top should lock in securely to the brew group. Then, the combination of very different materials (metal, acrylic, sealant) must be able to all hold together in temperatures rising and falling very quickly from room temperature to temperatures close to the temperature of boiling water, and huge pressure differences from the pressure in the room (on the bottom) to 8 or 9 bar (at the top). Plus, a coffee puck tamped inside, air and water flowing around...

    I can now imagine how the Spaziale team would maybe have felt the urge to push further and use their TPF more, but it's possible that it didn't hold that long and the manager, looking at the cost in time and materials, likely veto'd any further exploits.

    Stephens final TPF held out during a few tests in his workshop and it stayed in one piece during fifteen tests Roemer Overdiep and I did in Amsterdam on the Londinium I lever machine, but then it too began to give. One side is starting to pop open and from what I heard from Stephen, you do not want to be standing very close, peering at the looking glass, when it pops open en explodes hot water and coffee grinds in your face.

    Before we started documenting these TPF experiments, we rented a Sony 4K High Speed camcorder. It fits the Canon prime lenses we have available so we would not miss any detail.

    We also learned something we would maybe not have found out without the TPF: when using a tamper that fits very tight, it's best to tamp lightly. After finishing a firm tamp and pulling back the tamper, the puck can be pulled loose along the sides and this results in the puck jumping up and being slammed down again when the spring lever is being pulled. In a pump machine the puck will not jump up of course, but the seal along the outside of the puck will allow some initial flow.

    The "puck jump" happens very fast but is very clearly seen when we use the super slow motion feature of the camera. It hardly causes a problem but to get a nice and even flow when using a very tight fitting tamper, tamping lightly seems advised.

    When we used the tamper that fits my millennium La Pavoni Europiccola, that proved a very nice fit for Stephens TPF and the puck remained still, allowing the raised piston to suck in air through the puck instead of along the sides. Sadly, by the time we figured that out, the life cycle of the TPF was nearing the end and we couldn't risk damaging the $10.000 camera...

    For a short moment (elongated in the footage) there's a lot more coffee flying around in the TPF than I imagined there would be, but very swiftly, once the pressure is applied, all clears up and you can see the tiniest stream of water along the grains of coffee grinds and air and CO2 struggling to get out of the way.

    We cannot thank Stephen Sweeney enough for making this little project possible!
    Hi Johnathon,

    Is the above a quote or paraphrase from a secondary source, or is the "I" in the text actually you?

  15. #15
    Senior Member
    Join Date
    Apr 2010
    Posts
    558
    Quote Originally Posted by chokkidog View Post
    Hi Johnathon,

    Is the above a quote or paraphrase from a secondary source, or is the "I" in the text actually you?
    Straight quote from the HB site.

  16. #16
    Senior Member
    Join Date
    Aug 2013
    Location
    Rockingham W.A.
    Posts
    1,422

  17. #17
    Sleep is overrated Thundergod's Avatar
    Join Date
    Jul 2006
    Location
    Sydney
    Posts
    10,496

    Transparent portafilter


  18. #18
    Senior Member
    Join Date
    Mar 2012
    Posts
    1,275
    Interesting to see, but i do wonder how close it is to what actually happens in a normal basket where the puck is much closer to the shower screen and effectively has no "free surface" to interact with the brew water entering.

  19. #19
    Junior Member mcetp001's Avatar
    Join Date
    Aug 2012
    Location
    Adelaide
    Posts
    18
    That is fascinating.

  20. #20
    Senior Member
    Join Date
    Sep 2012
    Posts
    274
    Quote Originally Posted by blend52 View Post
    Interesting to see, but i do wonder how close it is to what actually happens in a normal basket where the puck is much closer to the shower screen and effectively has no "free surface" to interact with the brew water entering.
    I agree with this..

  21. #21
    Super Moderator Javaphile's Avatar
    Join Date
    Dec 2004
    Location
    Earth!
    Posts
    15,858
    With the puck not expanding until after the extraction is over unless you are over filling your basket the puck does indeed always have a "free surface". The only time this isn't the case is when you smash the puck into the shower screen when locking the portafilter on. In which case you're over filling the basket.


    Java "More Science!" phile
    Pete39 likes this.
    Toys! I must have new toys!!!

  22. #22
    Senior Member
    Join Date
    Mar 2012
    Posts
    1,275
    Quote Originally Posted by Javaphile View Post
    With the puck not expanding until after the extraction is over unless you are over filling your basket the puck does indeed always have a "free surface".
    Even so, 0-1mm "headspace" is not the same as water free falling 8-10 mm onto the puck.
    It occurred to me that filter baskets are designed to give minimal clearance between the screen and the puck surface, when correctly dosed....for a reason ?
    Interesting also that you assume the puck doesnt expand until extraction is over ?

  23. #23
    Senior Member
    Join Date
    Dec 2010
    Location
    Toowoomba QLD
    Posts
    417
    Quote Originally Posted by blend52 View Post
    Even so, 0-1mm "headspace" is not the same as water free falling 8-10 mm onto the puck.
    It occurred to me that filter baskets are designed to give minimal clearance between the screen and the puck surface, when correctly dosed....for a reason ?
    Interesting also that you assume the puck doesnt expand until extraction is over ?
    Are filter baskets designed to give "minimal clearance" or are they just designed to be just big enough to hold a reasonable dose?

    Have you ever observed a puck expanding during extraction?

  24. #24
    Super Moderator Javaphile's Avatar
    Join Date
    Dec 2004
    Location
    Earth!
    Posts
    15,858
    Quote Originally Posted by blend52 View Post
    Even so, 0-1mm "headspace" is not the same as water free falling 8-10 mm onto the puck.
    It occurred to me that filter baskets are designed to give minimal clearance between the screen and the puck surface, when correctly dosed....for a reason ?
    Interesting also that you assume the puck doesnt expand until extraction is over ?
    The water is not truly falling direct from the shower screen but rather it hangs on it until there's enough water mass for the bulge of water to break free and turn into a drop at which point it's already almost halfway to the surface of the puck. There's not a lot of force in a drop of water falling single digit mm distances. Additionally it is only impacting directly on the coffee for a short period of time before the water pools on top of the grounds. While the falling water may well account for the raising of the few fines we see there is no other observable impact that I can spot.

    The only thing I assumed about the expansion of the puck was the old adage that everyone had assumed to be correct that the puck expanded at the beginning of the extraction as the water soaked into the grounds. As for my statement that we now know it doesn't I assumed nothing. Nine minutes of high definition video including plenty of close up slow motion shots of extractions using a transparent portafilter under a variety of conditions showing that the puck does not expand until pressure is released at the end of the extraction convinced me that it was true, no assumptions necessary.


    Java "Some assumptions may have been harmed in the writing of this post." phile
    Dragunov21 likes this.
    Toys! I must have new toys!!!

  25. #25
    Senior Member
    Join Date
    Mar 2012
    Posts
    1,275
    Quote Originally Posted by Pete39 View Post
    Are filter baskets designed to give "minimal clearance" or are they just designed to be just big enough to hold a reasonable dose?
    Why else are 14,18,21 gm baskets all different heights and all appear to fill to the same " height below the rim" when dosed to those weights.
    Also have you ever tried a 10gm dose in a 20 gm basket ( hence puck height) ?...you have to adjust a few other factors to get any reasonable pour out if you do, and even then it certainly wont be the same " in the cup"

  26. #26
    Senior Member
    Join Date
    Dec 2010
    Location
    Toowoomba QLD
    Posts
    417
    Behmor Brazen - $249 - Free Freight
    Quote Originally Posted by blend52 View Post
    Why else are 14,18,21 gm baskets all different heights and all appear to fill to the same " height below the rim" when dosed to those weights.
    Also have you ever tried a 10gm dose in a 20 gm basket ( hence puck height) ?...you have to adjust a few other factors to get any reasonable pour out if you do, and even then it certainly wont be the same " in the cup"
    I think its because it aids easy volumetric dosing. If you fill a 14 g basket to the rim and screed it level (pre-tamping) you get pretty close to 14 g.

    I have never dosed 10 g in a 20 g, but I will try using my current dose of around 17.5 g in a 20 g basket and try and do some comparisons with an 18 g basket at the same dose (these are the only baskets I have). I do know that I have dosed as low as 16 g in the 18 g basket with no problems wrt the appearance of the pour using a bottemless PF and the cup result.



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •