Off centered water dispersion

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edwa

#1: Post by edwa »

I was reading the recent posts on tamping and then began to wander some related links and revisiting old threads on techniques. I wasn't attempting to troubleshoot any problem it was just idle reading. In one thread my eye was caught by a post that said for rotary pumps the water dispersion could be an issue in troubled pulls.

Without the PF in place I have noticed that my water flow is behind and slightly to the right of center does this have any bearing on extractions? My attempt to photo this was out of focus but at that moment I also captured the water flow bending in a slight 'S'. I imagine the off center pull is a result of how I've adjusted the machine's legs to aid the flow of my plumbed drip pan.

Before you ask, the extractions taste fine. This is more a question of what do other machines do as I only know the one in front of me.

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another_jim
Team HB

#2: Post by another_jim »

E61 groups all tend to be off center, since the water entry is angled, and the dispersion screw is not particularly sophisticated.

However, it will make no difference to the taste, since there is a long preinfusion that will evenly soak the puck regardless of how the water initially enters. You will get taste degradation if the puck hits the shower screen, since it means the water cannot flow evenly over the surface of the puck; but this is a problem even on machines that have very even water dispersion.
Jim Schulman

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Randy G.

#3: Post by Randy G. »

I suppose that depends on a lot of things. If the screen isn't perfectly flat or the brewhead is canted a bit or the machine isn't level it can contribute to an off-center flow. Even water surface tension or a speck or three of coffee or a hard water deposit can be a factor. As far as its affect on brewing, it also would matter how the flow cones through. If it is a strong, off-center flow then it might be a problem (like with a machine such as Silvia that starts the flow like a drag racer- foot to the floor), but with an E-61 that has a gentle flow until the PF if filled and there is a significant back-pressure it probably does not matter at all as long as there isn't a major flaw like a hole through the screen. I think that, regardless of the machine, once the headroom between the coffee and the screen is filled with water it wouldn't matter much at all... if at all.
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cafeIKE
Supporter ★

#4: Post by cafeIKE »

In pursuit of the answer to this question, more than a year ago I modified 2 e61 dispersion screws :




Repeated replacement has failed to divine any improvement in the cup.

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cafeIKE
Supporter ★

#5: Post by cafeIKE »

Minor point :
  • - the e61 has space behind the screen, so water can flow over the puck with coffee touching the screen
An updose and just set the tamper upon puck to level :



Run the pump for 3 seconds :



Knock out and cut puck :


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another_jim
Team HB

#6: Post by another_jim »

Oops, that's right, I forgot about the space above the shower screen - E61s don't need headroom.
Jim Schulman

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edwa (original poster)

#7: Post by edwa (original poster) »

Thank you gentlemen, this is definitely what I wanted to know.

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cannonfodder
Team HB

#8: Post by cannonfodder »

another_jim wrote:Oops, that's right, I forgot about the space above the shower screen - E61s don't need headroom.
But some E61 like groups do need puck to screen headspace. That may be why Elektra's don't like being updosed. There is no headroom above the screen. The screen screws directly to the dispersion block which has a bunch of tiny holes around it perimeter. If you don't give it adequate headspace, it will shower you with coffee spritzes. It also has a truly vertical water delivery.
Dave Stephens