Cleaning an espresso machine

[Jonathan Day]

Damned eGullet. Reading this forum led me to "CoffeeGeek.com" and I realised that the "grouphead" on the Pavoni machine I've been using for many years had never been properly cleaned. I remove the entire pump assembly from the machine from time to time and wash it out, removing coffee grunge from the rubber gasket that surrounds the dispersion screen. But how to remove the dispersion screen itself? The entire grouphead seems to be one seamless piece of metal.

Or is this one of those problems that I didn't know I had until I read about it here? The espresso the machine makes is good.

Would value any guidance from owners of a Pavoni pump machine. I don't know what model mine is -- it's old.

[phaelon56]

Look for some posts by "KoffeeKev" in the forums at Coffeegeek and email him or post there - he's in the trade and works on/rebuilds every imaginable type of machine - he might know.

I'll hazard a guess and suggest that what you need to get is a grouphead gasket at about $6 - $7 and you might just as well replace the "shower screen" (disperson screen) while you're at it. The screen will run about $12 or so. Look up into the grouphead at the screen and you should see a black rubebr gasket around the outer edge. On most machines of this type the outer edge of the screen is held in place by the gasket and it must be removed in order to throughly clean the machine. Typically a flat blade screwdriver is used to pry out the old screen and also used to carefully push in the new one.

If you can identify the specific model of machine, some good exploded parts diagrams are available here and they will likely have the parts as well

EspressoParts.com

If you still have pressure on the grouphead and don't want to mess too much with this it might be worth just doing a backflush with Cafiza or Purocaffe if you have not already done so..... if your machine has 3 way solenoid valves for pressure release after the shot is pulled, it's okay to do a backflush but check into this before just jumping in to do one. Once you've done the cleaning, make sure to do a through water flush and then pull a shot or two of espresso that will be discarded - best to make sure al the residue is totally cleared.

[phaelon56]

This coffeegeek.com tutorial may also help....

How To Clean a Dirty Grouphead

[Jonathan Day]

Problem solved. And it was a problem.

A search on Coffeegeek turned up a "forums" entry explaining how to open up the Pavoni. You remove the bar that connects the lever to the piston; you can then (gently but firmly) push the piston further down into the machine, forcing out the grouphead gasket, the dispersion screen and the piston behind that. When the bar is in place, the piston won't descend far enough to push out the gasket.

As far as I could tell, all the gaskets were in good shape. The base of the piston, however, was covered with coffee gunge, as was the dispersion screen. I washed and brushed everything (no soap!) until it was all clean. The piston went back in, and following Owen's suggestion I used a flathead screwdriver to ease the grouphead gasket back in place.

The machine now seems to work fine. As far as I can tell, there is plenty of pressure on the grouphead -- as there was before I cleaned it. The post-cleaning shots had a better taste, though the crema I get remains tan rather than the brown-red that shows up in some of the photos in this forum. But I suspect that this is because of the beans I am using.

Thanks for the referral to EspressoParts.com -- very useful!

[phaelon56]

The beans must be fresh - ideally between 2 and 10 days after roasting. You're also correct that crema varied from bean type to bean type. Some varietals produce farr less abundant crema than others - good espresso blends are optimized to produce a rich reddish brown crema.