Hi all,
Can someone please help me get rid of the 6 hole imprints on my puck.

This is my situation.
Using a naked P/F with a double basket & a RB flat tamper.
My machine is set to 9 bars.

I dose and distribute using the WDT method.
I've tried dosing 16, 17 or even 18g.
I know I leave enough space between the grounds and the screw,
No imprint of the screw on the puck.
I've tried light to heavy tamp.

But I still see the hole's of death on my puck.
The holes are all ways at the same place & same distance from each other.
Not all over the puck like I've seen on some of the pics here of channeling.
I'm thinking that it's due to pressure build up coming from the screen
I could see that it's due to were the water comes out of the group head screen.
I tried brushing and cleaning the screen.
But I still get the wholes.
Just for the record some times I only get 4 or 5 holes on the puck.

The size of the holes are not like pin holes they are more like nail holes.
They are also in a circle patter.

So what am I doing wrong or what should I be doing better.
Please help, any light in how I can get rid of this problem will sure help.

Thank you,
Michael

Hi Michael,

You mean holes like this:



or this:



?

I get that when I put less that 18g in my double basket on my Gaggia Classic. Don't know why I get it or how to eliminate it either:)

Cheers,
dsc.

dsc,

wow thanks for the pic. Sorry don't have any myself.
the 1st pic sure has the same size holes I get.

If you can imagine 6 holes in a circular pattern.
That's what I get imprinted on my puck.

Not always all the 6 holes come out on the puck

Sometimes I get 3 or just 4 in a circular patter.
It's always in the same pattern


Thanks again to anyone that can help

Maybe try dosing a bit higher? Is your puck wet and soupy when you're done pulling the shot? Do you get an imprint of the screen and screw on the puck after you're done? If not, you might be underdosing a bit, which can lead to pinhole (or in this case, nailhole) channeling. I know I get pinholes if I don't dose fairly high with my Anita.

I once found by underdosing I would get less channeling.

Maybe you can think of the water coming out of your group like anything being forced under pressure.

The futher it travels, the more the drop in velocity.

So if the puck is just about touching the group screen at the start of an extraction,the streams may shoot right through it.

But if you have a little distance between the screen & the puck, when the water hits it, it may get deflected & do whats it's suppose to do & not instantly go through the puck like a bullet.

I could be wrong, but this has worked for me.

I get it on the Elektra when the dispersion block needs to be cleaned (it's just above the shower screen, and has a screw that removes it, mostly the same one as for the shower screen itself). The Elektra block has six holes in a hexagon pattern; other machines have different patterns. When these get slightly clogged with coffee oils, they can spray hard enough to indent the top of the puck. The cleaning frequency depends on how small the holes are. The Elektra's are tiny, and I need to do it every month.

Kuban111 wrote:Hi all,
This is my situation.
Using a naked P/F with a double basket & a RB flat tamper.
My machine is set to 9 bars.

You don't tell us how old the machine is. It could be that you need to replace the dispersion screen. They aren't remarkably expensive (probably cost as much to ship as to buy the thing!) so it'd be a cheap experiment even if that's not it.

Hey guy's,

Thank you all for the very helpful input & replies.

My machine is only 1 month old, it was a floor demo model that daily grind had on sale.

It looked and smells new, I checked it out from top to bottom (my first machine).

I will try cleaning it and I believe I did get fewer holes when I under dose the basket.

I'm going to focus and experiment with under dosing the basket.


Any suggestions on amount of grams I should start at?


Thanks againg for everyones help.

If you've been grinding up 18 grams why not try starting at 14?