For quite a number of months I noticed that everytime I pulled a shot, there would be some splattering as it was being extracted. Now all of a sudden, for the past two days, I get this nice steady tight stream and the shots look and taste perfect. Does anyone have any idea what would cause some splattering during an extraction or cause you not to get that nice steady tight stream? Also is that even considered a problem or just one of those things that happen. The only thing I did a couple days ago was clean my grinder and start a new bag of beans but I do that all the time. To help with diagnosis I will list some facts about my machine and habits, etc.

* I have the Alex II heat exchanger and the mazzer mini doserless grinder.
* I pull at least 2 shots perday.
* I keep everything very clean. The Alex grouphead is cleaned with joeglo the 1st of every month and my grinder is cleaned after each 1 lb bag of coffee. I also clean the grouphead with just water after each use.
* I get fresh espresso from a local coffee roaster.
* I try my best to stay consistent with the amt of coffee, tamp pressure and technique, dialing in my grinder, water temp and pressure (9 1/2 bars), etc.

Can anyone shed any light on this. Any ideas or suggestions are appreciated.

Might sound stupid but it could be the weather. When temperature dropped here during the last days I also noticed some noticeable changes...

Or of course the beans, new bag could be different even if it's got the same label.

Splattering while extracting?
Have you tried a bottomless portafilter? Might reveal a little bit...

- Coffee that is too fresh
- Inconsistent distribution
- Clumping (Static electricity, humidity changes)

All the above. I have a high end grinder, I still use a dosing funnel and WDT each shot and carefully tamp. On newer beans, they can do this occasionally if my tamp is ever so slightly soft, or off.

I've read some good things about using a 58.4mm tamper instead of a standard 58, which I might aim for soon too. I don't like that I can wiggle my tamper around inside my VST basket so easily. There certainly seems to be a very thin rim around the perimeter of the coffee bed that is not properly tamped, and can lead to frequent channeling and crappy soft tan colored fast pouring shots that go right down the drain.

java70 wrote:...and pressure (9 1/2 bars), etc.

Can anyone shed any light on this. Any ideas or suggestions are appreciated.

Try a lower pressure - maybe the gauge is inaccurate.

Thank you all for your responses. I'm wondering if it has to do with the change in weather as a couple of you have stated. I have remained very consistent with everything since I brought the machine last January. Maybe a bottomless portafilter would be a good idea for me. I was curious if anyone had experience something like this happening. All I know is, all of a sudden the shots come out in a nice steady tight stream now.

Eric, I have never messed with the pressure settings since getting the machine. The factory settings seemed fine and the way the shots were being extracted were fine for the first number of months. But as the year went on it began to change. Now in the past 2 days, it went back to the way it was again. Thats why I'm wondering if the weather has something to do with it.

I'm open to any other suggestions or opinions from anyone else. It's much appreciated!