Shower screen water dispersion

[Buschy]

Excuse my ignorance...  :-? but I have noticed that the flow of water being dispersed from my e61 group shower screen changes.   Sometimes the water comes out from what appears to be all of the holes (like a shower ). Other times is just comes out in a single line or 2 lines (more like a stream(s) of water). Why? I assume it must have something to do with the amount of pressure behind the screen? No, the screen isnt clogged I checked...

If it changes because of pressure, does it automatically turn into "shower mode" once a full filter basket is locked in? How does it work? Have done a bit of a search but cant find the answer.

[Randy_G.]

Re: Shower screen water dispersion

The E-61 is a bit different from other brew groups. When there is no restriction to the flow of water, the system will not pump at full pressure (and possibly volume, but I never investigated that). So when you are just flushing water through without a loaded portafilter in place, the flow does not represent what actually happens during a pull. Once the PF fills with water and there is some resistance to the flow of water the valve in the group open fully and delivers full volume.

During an actual extraction, the area above the coffee is filled with water, so the actual pattern of water flows doesnt matter much as long as there are no jet streams to disturb the coffee.

As far as what you are seeing, it depends on things like water temperature, surface tension, cleanliness of the screen, etc.

I wouldnt worry about it....

[raphec]

Re: Shower screen water dispersion

There could be many possibilities. I am not entirely certain but i suspect it has more to do with the properties of water than anything else. When the water starts flowing, it starts in separate streams but due to its nature, water likes to stick to itself so as the streams touch at some point they join together to form one stream.

im fairly sure others here can explain it better than me, but essentially as the water flows out, the streams join and it forms a single stream from whihever point they join in.

When the puck is in the filter, it swells as the water hits it, causing it to push against the shower screen. This means the water coming out of the screen comes in at the point it is pushed out and has no flow distance to join up with other streams and is therefore evenly spread against the puck.

[robertmc]

Re: Shower screen water dispersion

Buschy

Ive noticed that when my machine hasnt been used for a while and I start a cooling flush the water sizzles out from all over the shower screen ( I think that Ive heard this referred to as the "water dance"). And when it cools down a bit it settles to a single flow from near the middle.  I use this to help me gauge how long to flush before locking in the PF

Robert