Here is an invaluable trick I learned from the former owner of H.E.R. (Home Espresso Repair) in Seattle some 15 years ago. You can get most* group head screens perfectly clean by heating them until red hot.
*Here are the warnings:
1) Donít use this method unless you are certain your screen is made from a solid, but perforated stainless steel plate. I cannot vouch for this technique on any other type of screen. If you have any doubt about this procedure, donít do it!
2) This will permanently change the surface color of your screen to a dull gray. This is a purely aesthetic detail however - you rarely see your screen unless you are cleaning it or photographing it to demonstrate cleaning techniques! But again, if you donít like the idea of your screen becoming a dull gray, donít do it!
3) This technique will generate smoke and quite often create dramatic flames as the coffee and coffee oils burn. If you are nervous about this, donít do it!
4) Red hot stainless steel screens are, well, red hot! Be careful! Donít burn yourself or anyone else! Have an open container filled with water nearby to quickly quench the heat of the screen and the end of your pliers! It is best to do this outside, but if you must do it indoors, do it under a stove ventilator set on high and away from all smoke detectors!
How to Clean Your Screen
1) Prepare your work area. Place an open container of water large enough to hold the screen near the place where you will be heating your screen. Understand that if you were to drop the red hot screen you could permanently damage whatever or whomever it might fall upon.
2) Remove your screen (made from a solid but perforated stainless steel plate) from all other related components such as the portafilter seal. If you like, you can reduce smoke and flames produced when heating the screen by first giving it a superficial cleaning.
3) Using a long-handled pair of pliers (bent needle-nose work well) place your screen into an open flame. Bunsen burners, propane torches, gas ranges all work well. I donít recommend cleaning your screen on electric range elements, however it does work.
4) Keep your screen in the open flame until it produces a dim red glow. About this time you will see some sparking and a little spitting if the screen is damp, followed by smoldering and smoking. If the screen becomes hot enough the smoke will often turn into a flame. This is not really a problem Ė in fact by burning as a flame, less smoke will be generated.
5) Wait until the portion of the screen in the flame stops smoking. If necessary rotate the remaining parts of the screen into the flame until they too have turned red hot and stopped smoking.
6) CAREFULLY cool the screen and your now-hot pliers by dousing them and keeping them in water.
7) Hand clean any remaining ash on the screen and replace.
I believe the brush pictured in this article is actually an Oxo GoodGrips brush, not an "Oxi". I clean a Livia, too. An excellent product for cleaning the brass dispersion plate is Bartender's Friend. You can get it at Sur La Table and other good kitchen equiment stores. It's lightly abrasive, it's high ph helps you polish, and it leaves no residue. IMHO, anyone polishing brass with dish soap, water and Scotchbrite is working way too hard. Sweet Maria's sells a small brush with "soft" stainless bristles that's specially shaped for cleaning the machined groove in the grouphead that fits the portafilter ears and it's adjacent upper surfaces. It's a very efficient tool, and it's too soft to damage the sealing gasket.
The cafe I work at aims to scrub and backflush each group head every 40 minutes. For home machines it seems reasonable to do this drill after a days use, while the machine is still hot. It becomes easy with experience and is not this much of a chore unless you're really neglecting it. A small screwdriver ought to remain as close at hand as your tamper.
cwillii1 Senior Member Joined: 20 May 2003 Posts: 1 Location: westminster Expertise: Aficionado
Posted Tue May 20, 2003, 4:05pm Subject: Cleaning Group Head
We recommend cleaning the group head at the end of every day to ensure the screen does not become clogged. We have seen some group heads that have needed to have a tourch used on them they were so bad. The torch method can either work or screw-up the group head. IT IS NOT RECOMMENDED! Buy a good cleaner and clean every day.
MarkPrince Moderator Joined: 19 Dec 2001 Posts: 5,609 Location: Vancouver, BC Expertise: Professional
Espresso: KvdW Speedster Grinder: Compak K10 WBC Vac Pot: A bit too many Drip: Clive Coffee Drip Stand Roaster: Hario Glass Retro Roaster
Posted Wed May 28, 2003, 2:39am Subject: Commercial vs. home
The comments are all great (though I fear the red hot recommendations ;)), but I should point out this is a maintenance routine for the home, not commercial use - it'd be ridiculous to do this kind of cleaning after every shot - most households may brew 2, 3 doubles a day, if that, so doing this once every few weeks (with lighter maintenance cleaning in between) is probably the best option.
sliv Senior Member Joined: 15 Oct 2003 Posts: 1 Location: San Diego Expertise: Advanced
Posted Wed Oct 15, 2003, 9:58am Subject: What If?
Very good instructions on cleaning the group heads; I quite agree that it should be done regularly and that compulsive backflushing is not a practical substitute. I, however, would really like to know how to disassemble groups with no screw head. I've heard that the trick is under the gasket, but I don't have one to practice on right now. Tips on this would clear my confusion-Thanks
cafewest_tech Senior Member Joined: 22 Aug 2003 Posts: 270 Location: Medford Expertise: Professional
Posted Wed Oct 29, 2003, 9:31pm Subject: Cleaning the group head.
I canít see what is wrong with taking the screen off the machines. With a single screw holding it on a couple times a week is nothing, for home machines. Not that hard and it only takes 5 minutes to do the whole job. Waiting till you have to burn the coffee residue off is lazy, and your espresso probably taste bad with all that residue turning rancid. Machines with electric 3 way solenoid's should only be backflushed with a blind filter basket, about every 200 shots, but then only after cleaning the dispersion screen and gasket first. Backflushing is hard on electric 3 way valves, thatís why it shouldnít be done more frequently. Machines like the Silvia should be backflushed only a couple times per year. Always use a good espresso machine cleaner when you use the blind basket to remove the oils and residue that accumulate in the lines and valve. Machines with the E61 group head can be backflushed everyday because they have a manual pressure release valve, and itís hard to remove their screen to clean. Use a espresso machine cleaner on your E61 every couple weeks and you can keep your group head spotless. Removing the screen on machines involves removing the gasket which holds the screen on. Something thin and be careful not to damage the brew head. Start on the outside edge of the gasket and gently slip your wedge in-between the gasket and brew head. Donít go in very deep, and wiggle the gasket down working around the gasket until the gasket comes off. Usually the screen comes with it. If not, grab the screen and pull down. To reinstall the screen and gasket. Place the screen on the table so as the screen is up and the flange is down. The gasket has a beveled edge on the inside and the bevel goes down on the screen. Grasp the screen and gasket and insert it onto the group head. Hold in place and take your portofilter with no basket in it. Insert into group head with screen and gasket in place, and tighten like your getting ready to brew a shot. Remove the portofilter and insert a basket into it. Crank portofilter into group head to finish seating the screen and gasket. If the portofilter will not crank into the group head your gasket is either upside down or you have the wrong type gasket. PS: The machine in the pictorial has a group head that can be removed from the machine for easy cleaning and gasket replacement. No need to twist your head to see if you have the thing clean.
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