Kristi wrote:So I guess it doesn't get dirty in there?
If you are doing water backflushes after each session and weekly espresso cleaner backflushes, you'll be disappointed how squeaky clean it is behind an E61's dispersion screen (yes, curiosity drives me to pop out the screen every couple months). Many home baristas simply replace the screen and gasket as a set when it no longer seals well and don't worry about destroying the gasket in the process by sticking it with an awl.
While this setup may seem like a pain, the advantage is there's nowhere behind the screen for grinds to hang up (no screws), so it's pretty easy to keep clean without disassembly. In the end, there's no practical reason to remove the screen before the gasket is shot as long as you keep the machine regularly maintained.
This is after a few weeks (shame on me!
)
If you look carefully, you can see the dispersion screen groove in the picture below. The "ungroovy" ones (left) usually have a thin metal ring spot-welded around the perimeter of the screen and a "dot" welded to the center, whose purpose is still a mystery to me. I've gotten both kinds off without nicking the gasket, but the ungroovy ones are more challenging (and I scratch the sides of them more).
Groovy on the right, ungroovy on the left
PS: See
How to clean dispersion screen for a list of more threads on the topic.