Weird puck texture

[Brewman]

Ive just bought myself a Pullman tamper, its a huge improvement on the sunbeam tamper because it fits snugly in the basket
Its cured my breakthrough issues but Im finding that the puck has a strange texture on top. Its lovely and smooth until about 5-10mm in from the edge of the basket. From here the entire centre looks as though the top 1-2mm of grounds have been washed away. :-?
The pour looks good and the coffee tastes as good as it ever has.
The puck looks dry and feels nicely spongey.
Am I doing something wrong? My guess was either underdosing or not enough tamp pressure however tamping harder does not change anything. Dosing up just gets it to hit the shower screen, making the puck stick to it and break apart- veiwing the puck then is a useless exercise.
Am I worrying about nothing?

[WSullivan]

Re: Weird puck texture

Sounds like channeling to me, how is it in the cup? Hows your distribution? Take us through you procedure from grind to pull, including all the taps knocks involved.
Cheers

[Brewman]

Re: Weird puck texture

Sounds like channeling to me, how is it in the cup? Hows your distribution? Take us through you procedure from grind to pull, including all the taps knocks involved.
Cheers

You asked for it

Anfim KS grinder paired with Sunbeam EM6910 machine.

Grind into basket circling around twice, filling about 3/4 full first circle then to 5-10mm above basket 2nd time around.
Two moderate taps.
Level off with straight edge.
Tamp down to almost second line in tamper, about 6-7mm down from lip. This requires reasonable force without being excessive.
Wipe sealing lip clean and place GH in head.
Hit button.
Takes 10-20sec for first drop.
Shot starts dark and gradually pales to caramel colour. Occasionally there is distinct striping.
No evidence of blonding.
Generally I kill the shot at 30sec and is close to 25mL

Occasionally I need more than 30 secs to get my 25ml shot, Ive had to push it out to 40-45secs several times but thta didnt concern me grreatly as it wasnt blonding, however the coffee was a bit lifeless. I still had the strange texture.
Im not sure about channeling although Im prepared to be corrected. When Ive had channeling previously it was distinct pits/wormholes, this is more like a coarse texture. Its very uniform/consistent in its placement -almost a perfect circle.

[acoggins]

Re: Weird puck texture

Hey Brewman,

Ive found that no amount of collapsing/tapping of the grounds, then levelling off with a butter knife can put enough in the basket for the level an EM6910 likes. Incidently I revisited this technique today and what I found was that the puck doesnt sufficiently expand to press against the shower screen. This results in weird channelling or bits of the puck sticking to the shower screen upon removal, resulting in the kind of thing youre describing.

You may find that with a fine enough grind, this produces a good quality shot, but its just .5 to 1 grams too little for a nice expansion against the showerscreen.

-ACog

[GregWormald]

Re: Weird puck texture

If you have a look Ill bet the puck is expanding and pushing against the shower screen to form the nice smooth middle. The puck is not expanding quite to the annular ring that is the washer around the screen, and that stays rough.

IMO--no issue.

At the same time Id be tempted to coarsen the grind a smidgen an try and get the 25-30 ml ristretto out in 25-30 seconds. This coarsening might also allow another gram or so of grounds into the basket and complete the expansion.

Greg

[A_M]

Re: Weird puck texture

Sounds like channeling to me, how is it in the cup? Hows your distribution? Take us through you procedure from grind to pull, including all the taps knocks involved.
Cheers

You asked for it

Anfim KS grinder paired with Sunbeam EM6910 machine.

Grind into basket circling around twice, filling about 3/4 full first circle then to 5-10mm above basket 2nd time around.
Two moderate taps.
Level off with straight edge.
Tamp down to almost second line in tamper, about 6-7mm down from lip. This requires reasonable force without being excessive.
Wipe sealing lip clean and place GH in head.
Hit button.
Takes 10-20sec for first drop.
Shot starts dark and gradually pales to caramel colour. Occasionally there is distinct striping.
No evidence of blonding.
Generally I kill the shot at 30sec and is close to 25mL

Occasionally I need more than 30 secs to get my 25ml shot, Ive had to push it out to 40-45secs several times but thta didnt concern me grreatly as it wasnt blonding, however the coffee was a bit lifeless. I still had the strange texture.
Im not sure about channeling although Im prepared to be corrected. When Ive had channeling previously it was distinct pits/wormholes, this is more like a coarse texture. Its very uniform/consistent in its placement -almost a perfect circle.

Double or single basket ?

If it is sloppy or sticks to teh shower screen... Then underdosing / and over tamping.. Been covered off on CS previously.

About 3mm below the rim after tamping ..

10-20 sec for the first drop and pull at 30sec... 10 sec is OK... If it was only starting to drop at 20 then its over tamped and or too fine...

Note: A double basket at 30sec...

See here for a snap at my first Nakid on an EM6910

http://www.youtube.com/watch?v=nFUxPvB4Ips&feature=related

[Brewman]

Re: Weird puck texture

Thanks for the advice folks. Knowledge is power!
Ill play with the dose and grind a bit more.

Im using a double basket.

When you say 30sec for the shot, is that 30 sec total from starting the pull or 30 sec from the first drop appearing? Im taking 30 sec after the first drop, so 40-50sec all up including the 10-20sec wait for the drop to start.

Ive tried the 5c piece trick but when I dose to get a nice impression I get a bad sticking of the grounds to the screen. The sticking always occurs around the edges of the screen where there are no holes and it tears away the top layer of the puck. The coffee still tastes good but you cant examine the puck.

GWs description is too close to the mark to be funny so my plan of attack will be to, in order
1) dose up
2) coarsen grind and dose up

[A_M]

Re: Weird puck texture

Thanks for the advice folks. Knowledge is power!
Ill play with the dose and grind a bit more.

Im using a double basket.

When you say 30sec for the shot, is that 30 sec total from starting the pull or 30 sec from the first drop appearing? Im taking 30 sec after the first drop, so 40-50sec all up including the 10-20sec wait for the drop to start.

Ive tried the 5c piece trick but when I dose to get a nice impression I get a bad sticking of the grounds to the screen. The sticking always occurs around the edges of the screen where there are no holes and it tears away the top layer of the puck. The coffee still tastes good but you cant examine the puck.

GWs description is too close to the mark to be funny so my plan of attack will be to, in order
1) dose up
2) coarsen grind and dose up

The time is from the start.. It is from when ya hit the button on the EM6910..

As to the blue comment above.. Never saw that other than when I SNAFU...

Grind size and tamp... 99% of mine always came out as a nice solid puck

Good pucks can be found here

http://coffeesnobs.com.au/YaBB.pl?num=1218451595/0

[acoggins]

Re: Weird puck texture

AM,

Shouldnt the timing really be from when the pump starts its full release? i.e. on my EM6910, when you hit the button you hear the pump pulse 3 times before it releases full presure. This is the pre-infusion time where water is essentially being dripped on to the puck.

Thats where Ive always timed from.

[A_M]

Re: Weird puck texture

AM,

Shouldnt the timing really be from when the pump starts its full release? i.e. on my EM6910, when you hit the button you hear the pump pulse 3 times before it releases full presure. This is the pre-infusion time where water is essentially being dripped on to the puck.

Thats where Ive always timed from.

Your technically 100% correct...  But the pre infusion can also be considered the start of the extraction process...

On a manual you may hit for a sec or two and then start your run..

Thus all things being = and that 2 + 2 = 5   what is a second or two...  Dow if you waiting to see the first drop - 10 - 20 sec after running and you count your extraction time from there...  That is a gross error.

The extraction starts as soon as water starts to flow onto or through ya coffee grinds...   To be anal we are always after extraction times  not pour times ...

While the Pour will be slightly shorter, there should not be significant differences...  Always remember 2 + 2 =5  

[Dimal]

Re: Weird puck texture

On an E-61 machine with inbuilt mechanical pre-infusion, for example....

The entire shot takes about 30 seconds after initiating the process and includes a 5-6 seconds delay while the pressure builds up in the pre-infusion chamber (essentially, an accumulator). Once the chamber pressure equilibrium is reached, the pressure continues to rise until the maximum brew pressure is reached. It is usually at this point (or slightly before) that one notices the first few drips of espresso falling from the GH Spout.

One would imagine that the automated process of the SB EM6910 tries to emulate a profile that is similar, in some way to this. In my Bezzera for example (Non E-61 Group), after hitting the Brew Switch, the pressure builds up quite quickly (typically within 2-3 seconds) and within another second or two after this the espresso stream is fully developed and stopped at between 25-28 seconds. I imagine that this would be similar for most non pre-infusion equipped machines.

Mal.

[A_M]

Re: Weird puck texture

On an E-61 machine with inbuilt mechanical pre-infusion, for example....

The entire shot takes about 30 seconds after initiating the process and includes a 5-6 seconds delay while the pressure builds up in the pre-infusion chamber (essentially, an accumulator). Once the chamber pressure equilibrium is reached, the pressure continues to rise until the maximum brew pressure is reached. It is usually at this point (or slightly before) that one notices the first few drips of espresso falling from the GH Spout.

One would imagine that the automated process of the SB EM6910 tries to emulate a profile that is similar, in some way to this. In my Bezzera for example (Non E-61 Group), after hitting the Brew Switch, the pressure builds up quite quickly (typically within 2-3 seconds) and within another second or two after this the espresso stream is fully developed and stopped at between 25-28 seconds. I imagine that this would be similar for most non pre-infusion equipped machines.

Mal.

Well put.

[Dimal]

Re: Weird puck texture

Well put.