[Homeroast] Turning Bottomless Portafilter

raymanowen at gmail.com raymanowen at gmail.com
Wed Aug 25 16:33:44 CDT 2010


"You never know when a jet might strike..."

I had 'em all over the place (3 or 4 at least) after I converted the
Crapesso by removing the three plastic flow-restriction discs from the
bottom of its portafilter handle. Pre- castration, there were four surfaces
facing each other that were inaccessible for cleaning- not a good situation.
Even my Simple Green/ Dishwasher detergent Witches Brew didn't clean it

The flow restriction would create back pressure with any grind and packing,
hence the plastic "tamper." Got a better one- 52.9mm tamper for the 53.3mm
filter basket or about 0.017" clearance. The Idiot Savant that designed the
machine had the theory that one is not bothered by things he cannot see. (Or
so said Marketing)

The "coffee jets" are a good indication that the packing and tamping are
uneven, otherwise, why would any filter perforation have more pressure and
flow than others ? In ideal espresso brewing, the packing is homogeneous and
the flow resistance generates the 9 bar back pressure. That pressure only
exists at the very top of the puck, and diminishes to Zero at the bottom,
for a melange brew. That's the way everyone likes it, so...

The flow restriction/ pressure regulation south of the puck is probably a
good idea, with a larger diameter pf = less pressure variation through the
puck. If the puck were just 1 grain deep, there would be no pressure drop
when the water passed the coffee field.

Which would be harder to cross,  an acre of corn in a 209' square field or a
mile long field, just crossing the narrow 8ft 3inch strip?

My demi just fits over the open bottom of the pf handle, so I just watch the
show through the glass. No apron needed. Different-sized porta filters
should brew and extract differently.

The fact that a few perforations spray out while the rest just flow is the
first step in  trouble shooting.  Don't ignore it- solve it and your
espresso just gets better. + Roasting, + Grinding.

Cheers, Mabuhay -RayO, aka Opa!
-- 
Persist in old ways; expect different results - suborn Insanity...


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