De-scaling (Espresso machine care and feeding)

Preventative De-scaling for the Gaggia Classic (and other single boiler, pump machines) - November 3, 2003

If your part of the country has hard water and you wish to prevent the premature death of your machine, you just may want to read on...

All of that steam capability of your espresso machine comes with a price. As soon as you hit the steam switch on the Gaggia, heating elements kick in to increase the boiler temperature well above the boiling point. However, all of the dissolved minerals in the water will start to precipitate out coating the valuable innards of your machine. Yes, you've got scale! Neglected for long enough, it will eventually clog your machine solid - the narrow passages of your steam wand, the heating elements and the inside of your boiler being the most susceptible to scale build up.

Unlike most other machines, the Gaggia has it's heating elements imbedded in the walls of the boiler, so scale on the elements themselves is not a problem. Most other machines do have their heating elements inside the boiler - a natural accumulation point for scale build up. If anyone has looked at the scale build up in an old kettle - you will know what it looks like. It's not a pretty sight.

So how can you prevent or even reverse moderate scale build up? Remember your high school chemistry class where you dissolved a piece of limestone with an acid? The same principle applies in removing scale build up. The acid solution dissolves the mineral deposits and washes it away.

What acids can we use to clean our espresso maker? Some have recommended such things as vinegar or lemon juice or various chemical descalers. Most agree not to use vinegar and how are you going to remove the lemon seeds from your boiler? Chemicals? - well, most espresso machines utilize some plastic piping of unknown composition, so personally, I wouldn't want to turn my machine into a science experiment. I would use the chemical acids only as a last resort.

You can definitely use those proprietary citric acid based descalers that the espresso machine manufacturers recommend, however the cheapest descaler to buy is citric acid. Citric acid is a naturally occurring fruit acid found in citrus fruits like lemons, grapefruit and oranges. Food grade citric acid can be purchased at health food stores or at winemaking supply stores.

This is not an exact science, so there are no strict guidelines as to how much citric acid to use. I believe that Jim Schulman recommends about 1 - 1.5 tablespoons to every liter (about a quart) of water. All espresso newbies should be forced to read his insanely long water FAQ. Go to google groups and search on the phrase "insanely long water FAQ". I would pay special attention in the FAQ regarding the extra TLC required for the Gaggia machines.

Here is how I would do a routine descale for my Gaggia (controls on other machines may work differently):

The Gaggia recycles wickedly fast, so I would be very careful not to flash steam a boiler full of citric acid! Therefore, I would turn the power switch on, hit the steam switch and immediately hit the brew/pump switch. The trick is to flush out as much scale from the wand as possible without superheating the citric acid solution. I would run the solution through the wand for maybe 10 seconds at a time or so - maybe a bit longer, however, I would not want the temperature ready light to come on! Turn off the steam switch after your purge. Contrary to the FAQ instructions, I think it would not hurt to flush the group a couple times as well. You may as well do a thorough cleaning by removing and cleaning the shower screen before doing this. Let the machine sit for about 20 minutes after each purge and repeat the procedure until the reservoir is just about empty.

Clean out the reservoir, fill with fresh water and flush it through the group and the wand. Don't forget to put back your newly cleaned shower screen. Brew a shot to season the machine and discard. You are set to go for your next brewing session.


Glenn lives and works in Southern Ontario as a senior financial advisor. His passion for coffee and espresso keeps him looking for the better brew. He has been a regular with the CoffeeCrew for several years now.


Goto Chapter Two of the Guide to Espresso Care and Feeding.