Exceptional espresso is the culmination of many factors. Obviously the coffee itself is first and foremost, supported by the barista's technique and the capabilities of the equipment. One factor that is often overlooked in commercial establishments and homes alike is the foul flavors that poorly maintained espresso machines can introduce to the cup. As you will read, the sense of "clean" this article advocates doesn't mean wiping down the driptray and running water over the portafilters before closing, it means a regular cleaning regime that removes impurities on an hourly, daily, and weekly basis. Don't be put off by the detailed-oriented nature of the task—the reward is genuinely better and more consistent espresso.
This article has several authors. Dave Stephens introduces why cleaning must be a regular part of your barista duties and how to perform them with step-by-step instructions focused on the business-end of your espresso machine. Nick Griffith outlines when these cleaning duties need to be performed. Finally, Chris Tacy explains the salient differences between the cleaning regimes for home and commercial establishments. The instructions and recommendations presented generally apply to any espresso machine with a three-way valve type group; feel free to adapt these instructions to your own personal use. In doing so, you remove one impediment standing between you and great espresso.
Related: Grinders are not "self-cleaning" and can harbor rancid oils that taint your espresso. How to Clean a Mazzer Mini explains how to remove the burr assembly and properly clean the grinding chamber.
The best coffee beans cannot make up for the impurities a dirty machine adds to your drinks. Coffee beans contain essential oils. While these oils are responsible for the rich crema that tops your espresso, it can also be responsible for a rancid off flavor that develops over time. Those oils emulsify and cling to and behind the water screen of your espresso machine, doubly so on brass surfaces. These oils also leave a film on the filter basket and portafilter. Over time this film will start to plug the holes of the filter basket and create deposits inside the portafilter spout. Luckily these impurities are relatively easy to remove IF you follow a regular cleaning schedule.
Does this sounds a little excessive to you? Perhaps it will help to see what a portafilter might look like after a hard day at a busy café if it's not cleaned properly (shown next to new portafilter):
Of course nobody should ever let their portafilter reach this degree of filthiness. The results in the cup with be dramatic and unpleasant. Even in a café this is not acceptable, though there one has the (weak) excuse of being very busy.
Keeping your espresso machine clean will not only help maintain the quality of your espresso but also extend the life of the machine. You should purge and wipe off your steam wand after every use and run a water shot through your machine after every brewing session. Do a clean water backflush every 10 to 15 shots and at the end of every session as part of your cleaning routine. This section will concentrate on the more detailed cleaning routine that should be performed every week or 20 to 30 shots, whichever comes first.
IMPORTANT: Only machines with a three-way valves can be cleaned using methods described in this article. If your espresso machine does not have a three-way valve, do not attempt to backflush as doing so can damage your espresso machine. Please consult your operator's manual to verify the presence of the three-way valve (often called a three-way solenoid).
by Dave Stephens
Below we have a prime example of a dirty machine. There are milk deposits on the steam wand and coffee residue and oils on the shower screen. You should wipe off the shower screen with a moist cloth at the end of each session and the steam wand after each use (one dedicated to each task to avoid cross-contamination). Once a week (or more often depending on your usage), do a more detailed cleaning as described below.
Dirty shower screen (l) and dirty steam wand (c) before
and after cleaning with these instructions (r)
You will only need a few items to adequately perform your cleaning:
Optional components include:
Start by simply wiping off the residue on your shower screen. Now gather up your portafilter, backflush basket and flushing detergent. Please read the instructions on your detergent and use their recommended dosing. I am using JoeGlo. They recommend using ½ teaspoon of detergent in your blind basket. Snap the blind filter basket into your portafilter and add the recommended amount of detergent.
Follow the recommended flush sequence of the detergent you are using. JoeGlo recommends running the pump five times in 15 second start/stop intervals. Once the portafilter is locked into place, engage the pump. You will notice a change in the pitch of your pump as the pressure increases. Turning off the pump automatically opens a pathway from the brew group to the drip tray; you will hear the distinctive "whoosh" as the water escapes.
This release of pressure will force the dissolved detergent back through the dispersion screen and the three-way valve. Flushing those spoiled essential oils out of the system will not only improve your espresso taste, but also clean the three-way valve of oils and grind deposits so it seals properly. With some vibration pump machines, the pressure increase will trigger the over-pressure valve to vent excess pressure back into the water reservoir or drip tray. In this case, turn off the pump once this occurs.
One trick to aid you in your cleaning after each session is the "portafilter wiggle." Once you have backflushed with cleanser, loosen the portafilter and hold it in place on the brew head. Engage the pump. The blank filter basket will fill with water (and cleanser) until it flows over the edge. Give the portafilter a wiggle to help clean the oils and residue from the group head gasket. Be careful, hot water will splash! You cannot see in the photo, but I have water splashing over the drip tray. If your boiler is at full temperature, this water will be very hot, so take care not to burn yourself.
If you elected to purchase a group brush, this is where you will use it. You need to clean any deposits from the portafilter gasket, the group head threads that the portafilter locks into and the rolled edges of the shower screen. Simply insert the brush into the group head and scrub. I use a dishrag dipped into some dissolved flushing detergent to wipedown the gasket groove, using the groupbrush to guide the dishrag along. Once completed, do not forget to brush and rinse the grouphead with clean water (using the "portafilter wiggle" again) to remove any residual detergent.
After the flush sequence and portafilter wiggle, remove your portafilter and drip tray. You many notice small coffee particles and a dirty brown tint to the water. This is the gunk responsible for that rancid flavor in your espresso.
Rinse out your drip tray and blank basket to remove any un-dissolved detergent. If there is no detergent left and the water is still brownish in color, you need to repeat the cleanser backflush with more detergent.
Reinstall the drip tray and lock your clean portafilter back into the machine and repeat the backflushing process with clean water. This time you will be flushing out any remaining detergent from the brew group. Refer to the instructions on your detergent for the recommended number of cycles (generally the same number of cycles as for the detergent; "rinse thoroughly" is the operative phrase).
Now that you have cleaned the internal workings via a backflush, you can now clean the exterior surfaces. Simply wipe the shower screen with your dishrag.
Next clean the steam wand. Take the clean wet dishrag and wipe the exterior down. If you have a steam wand brush, clean the inside of the steaming wand (though if you need to use such a device, it indicates you are not purging and cleaning your wand well enough after each use). Unscrew the tip from the steam wand, dip the brush in an appropriate cleanser and run it up the steam tube.
Note: Most backflush detergents are quite toxic and not suited for this task. I recommend clean water. Urnex does make a product specifically designed to clean steam wands called Rinza, and PuroCaf has their own dairy cleanser as well. Both of these products work very well and are highly recommended for soaking the wand and tip.
Remember to purge the steam wand after cleaning by opening the steam valve and venting it into an appropriate container for about thirty seconds.
Now that the espresso machine is nice and clean, turn your attention to the portafilter and basket. First, you'll need to rinse and wipe clean the basket. Second, you should break down your portafilter (remove the spouts and disassemble any cover the spouts may have). Once you've done this, take your green scrubby square and thoroughly scour the inside surfaces of the portafilter body and the spouts. Do not use the scrubby on your basket as you will enlarge the holes.
Find a large container to hold them and pour enough water into the container to submerge them. Add some of your cleaning detergent to the water and stir to dissolve. Refer to the directions on your detergent to get the correct dosing for the volume of water, JoeGlo recommends 1 tablespoon per quart of very hot water. Place your parts into the detergent water and allow them to soak for at least ½ hour.
Note: It is inadvisable to allow the plastic, Bakelite or rubber handle to be submerged in the water. Some handle materials can be damaged by the cleanser and over time all will suffer rust and damage to the internals of the handle.
After the soak, rinse all of the parts with clean water, repeat the green scrubby scour, and then wipe dry with a dishrag. If the portafilter spouts are the open-slot type, visually confirm that there's no trapped oils the soaking didn't dissolve; use a small round brush to scrub it clean (don't laugh, but the brushes designed for cleaning baby bottle nipples are cheap and work well). Reassemble.
Wipe down the exterior of the espresso machine to remove any surface dirt and reassemble. Now you are ready to pull shots and steam milk until the next cleaning. Please note that it is always a good idea to pull one garbage 'seasoning' shot at the beginning of the session that follows a full cleaning. This assures that any residues are indeed flushed away and lubricates the surfaces of the three-way valve of lever-type E61 groups, eliminating "lever squeak" after a chemical cleaning.
Reminder: In addition to replacing the water in the reservoirs of pourover machines every other day, remember they need regular cleaning too!