Hi,

I've bought a naked PF for my new 2nd hand PV Export.
This PF has "smaller ears" compared to the older stock PF and locks at 4 o'clock in stead of 6 o'clock.
But no leaks.

It seems impossible to get a nice centered and donut shape extraction with the double basket. Low/high dose, light/firm tamp, slow/fast flow, it doesn't matter. Every shot I get almost no flow from the centre but a couple of streams from the edges. Not only the edges of the basket but the edges form the boundaries of the PF itself. It looks like massive side channeling but colour and taste is pretty good.

I'm pretty convinced that I know how to dose and distribute and I only use freshly roasted coffee (maximum three weeks old after roast). The pharos makes a pretty decent grind as do my other grinders. With my pump machine never had any difficulty.

Strangely I do get nicely centered and donut shape extractions with the single basket that should be way less forgiving than the double basket.

I've made a (worse) video here with my smart phone to illustrate this. It's made with 12 grams, fine grind and only a levelling tamp. This one has a slow flow but as said before that doesn't make a difference.

http://dl.dropbox.com/u/51884816/VIDEO0003.3gp

Anyone any ideas what's going on here?

On page three of this thread I show a couple of bottomless pours - they are more or less "right down the middle" as they say. I grind fine AND dose full, including a light but firm tamp. I no longer tap the edges of the basket to settle the grinds. I also always "double or triple fill' the basket, by filling, compressing with the tamper, then filling again.

Videos of lever espresso machine routines

yes I know it should be possible because I've seen more examples.
this morning a short session just before work:
*2 single basket shots with 8,5 grams and a light tamp; one 1/2 pull + 1 complete pull: perfect donut shape pours; about 18 grams / 25 cc per shot
*2 double basket shots with 16 grams each and a firm tamp; two 1/2 pulls + one complete pull; about 25 grams / 30 cc per shot; only coffee form the edges of the basket and PF!
It doesn't look and taste like massive side channeling; no signs of blonding, no sudden increase in flow, no spirtzers, balanced taste. Puck knocks out in one piece and has no holes.
Wondering if the stream in the centre is somehow attracted to the sides, but by what forces?
Tastewise the PV is an amazing machine and it gives the barista great shot control!
And I'm only starting to get to know this little machine...

Try adjusting the grind a little - if it feels a little too fast tighten it one notch. If it seems a little too slow loosen it a little.

I can say that my first half pull often offers so much resistance that very little espresso falls (I attempt to get only one drop into the cup in fact). My belief is that this first half-pull is only for thoroughly wetting the puck. The second half pull drips - just when it begins to start a steady stream I stop it, gently pull it down, and go for the whole pull.

Also, try to "be one" with the lever, gently starting and stopping it.

PC

I forgot to add that the aroma of roasted coffee rising over the machine during this process is a hint that things are progressing towards espresso nirvana.

Yes I've done multiple experiments with many grind settings. Flow speed has no impact in this regard. But it does have a big influence on taste of course

I read in a post on coffeesnobs:

"Another idea with the PF's is to go naked and have the base cut off. I have just done this with mine. I have realised that you should remove the entire base, leaving just a collar that ends above the base of the double basket. Otherwise the coffee will flow to the edges of the basket and touch the edges of the pf- producing an uneven flow."

My collar is below the base of double the basket and edging inwards. With the single basket there is a bigger distance between the basket and the collar and I'm having no trouble at all to get a nice single stream of coffee at all.

Strange.

Anyway, I'm in love with the way shots are tasting...even without a nice centered single stream...

FWIW, I have the exact same problem on my cremina with the Elektra double basket (bigger than the stock one). I can't figure it out either. My hunch is that my DIY bottomless pf isn't bottomless enough, but I can't seem to understand why this would matter. Magnetic field?!?!?!

Coffee makes a difference too. Try some stale Italian espresso roast.

Yes, but what if I'm getting a good naked extraction with stale Italian coffee blends (northern/southern style?) and I'm preferring fresh roast single origen coffee

Perfect centered stream of coffee with the single basket using 9 grams of a SO from Guetemala.

http://dl.dropbox.com/u/51884816/IMAG0102.jpg

I thinks I'm going to cut of the collar from the naked PF and see if this helps with the doubles.

Please post your results!