Coffee Machine Cleaning and Maintenance

It’s easy to watch hours of videos of latte art and to pull shots perfectly, but if you’re looking to serve a great-tasting cup of coffee, making sure your espresso machine is clean is where you need to start.

By neglecting a proper maintenance routine, you can end up with a bitter cup of coffee or, even worse, an espresso machine that won’t work at all. Cleaning an espresso machine isn’t difficult, but it requires knowledge of the appropriate cleaning products and techniques.

Don’t forget that an espresso machine is likely one of the biggest investments for any café, so keeping it in good operational condition is common sense, even from a financial standpoint.

Before we begin, we should clarify that we primarily had cafe owners and baristas in mind when we created this list. While most of these guidelines should apply to domestic coffee machines and grinders, please note that a basic coffee machine may not have all the features of a commercial one.

What are the common pitfalls to avoid when maintaining various coffee brewing devices?

Maintaining coffee brewing devices is crucial for both the longevity of your equipment and the quality of your coffee. Neglecting care can result in poor-tasting, bitter, or metallic coffee, or even cause your machine to stop working entirely. It can also significantly reduce the resale value of your equipment.

Here are common pitfalls to avoid across various coffee brewing devices:

Espresso Machines

Ignoring Water Quality

To maintain your coffee machine, be aware that scale buildup from hard water can cause costly repairs and slow water flow, which is an early indicator that descaling is needed. Additionally, corrosive water chemistry can damage the machine, and biofilm accumulation can occur if water is left in the tank for too long, which will affect the taste of your coffee.

Neglecting Daily/Frequent Cleaning

Neglecting to purge the group head after each shot allows grounds and residue to accumulate on the diffusion screen. If a shot chokes, the stronger liquid forced back into the machine makes immediate flushing crucial to prevent deposit buildup.

Failing to backflush the brew group regularly (daily for commercial machines, weekly for home machines) causes coffee, grinds, and oils to be sucked back into the group head and valve, leading to soluble deposits in internal tubes that negatively impact coffee taste. Not purging the steam wand immediately after steaming milk encourages milk residue and bacterial growth.

Uncleaned portafilters and filter baskets allow loose grounds and coffee oils to build up, affecting coffee flavour. Daily cleaning of group head shower screens is important to prevent more difficult cleaning tasks if neglected. Lastly, allowing mould to grow in the drip tray is unsanitary.

Improper Cleaning Techniques

Avoid submerging plastic portafilter handles in cleaning solution, as this can cause wear. For E61 group heads, backflushing with detergent more frequently than every few months can lead to premature gasket wear.

Soaking the entire steam wand, rather than just the tip, can, in rare instances of poor seals, draw milky water into the steam boiler, which is highly undesirable. Lastly, using abrasive materials to clean the external casing may result in scratches.

Descaling Mistakes

Old scale buildup can be exacerbated by using a gentle descaler, as it can loosen flakes that clog narrow parts like flow restrictors, making them difficult to clear.

Furthermore, for machines with aluminium boilers (e.g., Gaggia), avoiding manufacturer-recommended descalers and opting for citric acid can cause corrosion. Lastly, diluting expensive commercial descalers more than recommended results in an ineffective solution.

Neglecting Wear Parts

Not replacing the group head gasket and diffusion screen annually can lead to an imperfect seal and leaks, as these parts become brittle over time. A worn shower screen can also impact water flow.

Coffee Grinders

To maintain your coffee machine, avoid neglecting the exit chute, as this can cause coffee to accumulate, leading to regrinding, increased fines, and a worse taste; clean it at least weekly.

Leaving beans in the hopper for too long allows oils to deposit and go rancid, resulting in a “fishy” taste. When cleaning the hopper, water alone is insufficient to remove these oils; a little detergent is needed.

Never use uncooked rice to clean your grinder, as manufacturers strongly advise against it. Rice is harder than coffee and can damage the burrs, voiding your warranty. Dedicated grinder cleaning pellets are a safe alternative.

Finally, replace dull burrs promptly, as ignoring them can lead to a sudden increase in fines and hotter ground coffee, negatively impacting taste and performance.

Other Coffee Brewing Devices

Filter Coffee Brewers

Anything that repeatedly touches coffee will acquire unpleasantness if not cleaned regularly. While tubes are wider than in espresso machines, neglecting to descale can still affect performance.

Kettles

Allowing scale to build up in kettles due to hard water is a common pitfall.

Moka Pots

Not cleaning Moka pots thoroughly is a common mistake; the “patina of dirt” is not seasoning, it’s just dirt and needs to be cleaned. Additionally, not changing the rubber gaskets when they become brittle or cause pressure leaks will affect brewing performance.

What parts of an espresso machine need regular maintenance?

Regular maintenance of an espresso machine is crucial for ensuring delicious coffee, maintaining the machine’s functionality, and extending its lifespan. Neglecting these tasks can lead to bitter or metallic-tasting coffee, an inoperative machine, and a reduced resale value.

Here are the parts of an espresso machine that require regular maintenance:

Water Quality and Tank

Maintaining your coffee machine effectively requires attention to several key aspects, beginning with water quality. Using water that is too hard is a common issue, as it leads to scale buildup within the machine, potentially necessitating expensive repairs. Corrosive water can also cause damage. To assess your water’s hardness, you can use a testing strip. For home machines with a reservoir, consider using BWT water softening pouches or Third Wave Water packets with distilled water. If your machine is direct-plumbed, cartridge-based water softening and filtration systems are available options.

Regular cleaning of the water tank is also crucial. Avoid letting water sit in the tank for extended periods, as this can lead to the accumulation of a biofilm that negatively impacts the taste of your coffee. If the machine has been idle for some time, the water should be changed.

Finally, descaling is a vital maintenance step that involves adding an acid dissolved in water to break down limescale. The frequency of descaling depends on your water’s hardness. For newer or recently descaled machines, a reduced flow rate from the group head can serve as an early indicator of scale buildup.

If you have very hard water and haven’t descaled in years, be aware that a gentle descaler might loosen scale flakes that could then clog narrow components like flow restrictors (typically 0.6-0.8 mm wide), which are difficult to clear. In such severe cases, a much higher concentration of descaler (e.g., 20% acid by weight) left for a longer duration might be more effective in breaking down a significant amount of scale.

It’s important to note that some machines, such as Gaggia models with aluminium boilers, may advise against the use of citric acid due to corrosion concerns, recommending manufacturer-specific descalers instead. After descaling, thoroughly flush the machine with fresh water until no sour taste remains.

Portafilters and Filter Baskets

Daily cleaning of the filter basket is crucial to prevent the accumulation of loose grounds and coffee oils, which can negatively impact the taste of your coffee. After each use, knock out the coffee puck and rinse the portafilter basket with a quick flush from the group head. For significant accumulation, deep cleaning involves soaking the parts in very hot water with espresso machine cleaning powder. However, avoid submerging plastic portafilter handles, as this can cause wear over time. Soaking for 10-15 minutes, or even overnight for a more thorough clean, followed by rinsing and brushing, is recommended.

Group Head and Shower Screen

For optimal coffee machine maintenance, daily cleaning of the group head shower screen is recommended. This screen, which evenly distributes water to the coffee puck, quickly accumulates residue. To clean, unscrew and separate the screen into its components (screen, metal plate, screw). Simmer these parts in hot water with cleaning powder for 10-15 minutes, then brush them clean. This process is more effective when done daily.

Additionally, preventing buildup is crucial. Purging the group head for a few seconds after each shot rinses away grounds and residue from the diffusion screen, preventing bitterness and harshness in your espresso. Using a puck screen can also reduce residue accumulation around the shower screens. Finally, when the shower screen is removed, the dispersion block (the water source) should also be wiped clean, as coffee slowly builds up there.

Backflushing the Brew Group

Backflushing is a crucial maintenance step for espresso machines. For commercial machines, it should be done daily, while for home machines, weekly backflushing is sufficient. This process addresses the issue of “coffee water”—a mixture of coffee, grinds, and oils—being sucked back into the group head and valve after an espresso shot due to a vacuum created by the solenoid valve. Over time, this “coffee water” can deposit solubles within the machine’s internal tubes. Backflushing utilises a blind filter basket with a cleaner to push hot water and detergent back through these internal components, effectively clearing accumulated oils and residue.

To perform backflushing, insert a blind filter basket containing half a teaspoon of cleaner. Lock the portafilter into place, then activate the brew cycle for 10 seconds, repeating this process 5-8 times. Afterwards, remove the portafilter, rinse the group head thoroughly, and then re-insert the portafilter with a clean blind filter for a final rinse.

While daily backflushing with detergent is recommended for commercial machines, for home E61 group heads, detergent backflushing should only occur every few months. More frequent water backflushing can supplement this to prevent premature gasket wear. Additionally, if a shot flows too slowly (known as “choking”), the liquid drawn back into the machine is significantly more concentrated. In such cases, immediately remove the portafilter and flush the group head for about five seconds to help prevent the accumulation of this stronger liquid.

Steam Wand

Immediately after steaming milk, the steam wand must be purged and wiped with a hot, clean cloth to prevent residue buildup and bacterial growth. For a more thorough deep clean, the tip of the steam wand can be removed and soaked in hot water with a cleaning solution like Cafetto MFC or Rinza, followed by a thorough purge. Avoid soaking the entire steam wand, as a poor seal could, in rare cases, pull milky water back into the steam boiler.

Drip Tray

The drip tray should be removed, emptied of coffee grounds, and wiped clean with a soft, wet cloth regularly. Allowing mould to grow in the drip tray is unsanitary and should be avoided.

External Casing

Clean the external casing with a soft, wet cloth and buff dry with a separate cloth or paper towel. Avoid abrasive materials that could cause scratches.

Wear Parts

Group Head Gasket and Diffusion Screen: These are wear parts that become brittle and can form an imperfect seal over time, leading to leaks. It is recommended to replace them annually, or more frequently if pulling many shots. They are inexpensive and easy to replace.

How to clean the portafilters?

Cleaning portafilters is crucial to prevent the build-up of loose grounds and coffee oils, which can significantly affect the taste of your coffee, often leading to metallic or bitter flavours. Proper maintenance ensures delicious espresso and contributes to the longevity of your machine.

Here’s how to clean your portafilters:

Daily/Frequent Cleaning

To maintain your coffee machine, rinse the portafilter basket with a quick 2-second flush from the group head after each shot to remove grounds and residue. The filter basket should be kept clean daily, both inside and out. After each coffee-making session, remove any retained liquid from the portafilter, as leaving it in a hot machine can lead to unpleasant deposits. At least weekly, wash the basket with dish soap and a sponge or soft scour to remove old coffee accumulation; the inside of the basket should be clean enough to pass the “finger test.”

Deep Cleaning/Soaking

To ensure thorough cleaning, it’s recommended to soak your portafilter basket every few weeks to remove stubborn residue. For significant accumulation, a deeper soak may be necessary. To prepare, place the portafilters and filter baskets in a metal bowl or sink. Add one tablespoon of espresso machine cleaning powder (such as Puly Caff Powder, Cafetto Evo, or Urnex) or a teaspoon of espresso machine cleaner. Fill the bowl with very hot water to submerge the metal parts. Let them soak for 10 to 15 minutes, or for an hour or even overnight for a more thorough clean. Crucially, avoid submerging plastic portafilter handles, as this can cause wear; only dip the metal parts. After soaking, remove the parts, rinse them thoroughly with hot water, and brush off any remaining coffee grounds. If stubborn residue persists, give them a light scrub. Finally, place the filter baskets back in the portafilters and leave them on the group head overnight.

Think of cleaning your portafilter like cleaning a frying pan – you want to cook every meal in a fresh, clean pan, not one with yesterday’s remnants.

How to backflush a machine?

Backflushing is a crucial maintenance step for espresso machines, primarily designed to clean the internal components of the brew group, particularly the solenoid or three-way valve. When an espresso shot finishes, the machine’s valve creates a vacuum that draws “coffee water” (containing coffee, grinds, and oils) back into the group head and internal tubes. If not regularly cleaned, these parts accumulate deposits, leading to poor-tasting coffee, often described as metallic or bitter, and can eventually cause the machine to malfunction.

Here’s how to backflush your espresso machine:

Frequency

Backflushing the brew group is a key maintenance task for espresso machines. Commercial machines require daily backflushing, while home machines can be backflushed weekly or daily, with more frequent cleaning leading to better-tasting espresso. For E61 group heads, it is recommended to use detergent for backflushing only every few months, supplementing with more frequent water backflushing to protect gaskets from premature wear.

Materials Needed

• A blind filter basket (a filter basket without holes).
• Espresso machine cleaning powder or tablets, such as Puly Caff Powder, Cafetto Evo, or Urnex. A tiny amount of powder is often sufficient for frequent cleaning.

Step-by-Step Process

1. Prepare the Portafilter: Insert a blind filter basket into your portafilter.
2. Add Cleaner: Add about half a teaspoon of espresso machine cleaner into the blind filter basket. If using powder, a tiny amount is often enough.
3. Lock In: Lock the portafilter with the blind filter and cleaner into the group head.
4. Activate & Pause: Activate the brew cycle for 10 seconds, then turn it off.
   • The cleaning begins when the machine is off and the pressure drags the detergent up into the machine’s internal tubes, allowing the detergent to dissolve accumulated oils and residue.
5. Repeat: Repeat this on-off cycle 5 to 8 times. You can vary the timing, such as shorter “on” times and longer “off” times, to be just as effective.
6. Rinse (Initial): After the detergent cycles, remove the portafilter from the group head.
7. Rinse (Group Head): Activate the brew cycle again for a few seconds to rinse the group head, ensuring no detergent remains.
8. Rinse (Final Backflush): Re-insert the portafilter with a clean blind filter basket (without detergent) and rinse again by repeating the brew cycle activation and pausing a few times. This helps to flush out any remaining cleaning solution. Continue flushing until the water coming out looks and smells clean, and no sour taste remains.

Important Tips and Precautions

Immediate Flush for Choked Shots

If you pull a shot that flows too slowly (“chokes”), the liquid sucked back into the machine is significantly stronger and contains more soluble material. Immediately remove the portafilter and flush the group head for about five seconds to prevent this stronger liquid from accumulating inside.

Preventive Flushing

Purging the group head for a couple of seconds after each shot helps to rinse away grounds and residue from the diffusion screen, preventing buildup. This action brings clean water through and helps to drag out residue before it deposits.

Puck Screens

Using a puck screen can also help to reduce the amount of residue that ends up inside the group head.

Read Your Manual

Always consult your machine’s manual for specific cleaning and maintenance instructions, as processes can vary slightly between machines.

No Such Thing as “Too Clean”

A machine cannot be too clean; it can, however, very easily be too dirty, leading to compromised coffee taste.

How to clean the group head screens?

Cleaning the group head screens is vital because they evenly distribute brewing water to the coffee puck and are in constant contact with coffee, quickly accumulating dirt. Neglecting this can lead to bitter-tasting coffee and make future cleaning more difficult.

Here’s how to clean your group head screens:

Frequency

• For commercial espresso machines, it’s recommended to clean them every day.
• For home machines, the minimum frequency for a regularly used machine is weekly, but there’s no reason not to clean them more frequently if desired.
• Every few weeks, it’s recommended to remove your machine’s diffusion screen and portafilter basket to soak.

Materials Needed

• A screwdriver (flathead, Phillips head, or other, depending on your machine) to unscrew the screen.
• Espresso machine cleaning powder (such as Puly Caff Powder, Cafetto Evo, or Urnex).
• A brush.
• A soft scour or sponge and dish soap for scrubbing.

Step-by-Step Process

1. Disassemble the Screen
   • Unscrew the screw holding the group head shower screen.
   • Carefully separate the three parts: the shower screen, the metal plate, and the screw. Some machines may only have a screen or a screen and a dispersion block.
2. Soak the Parts
   • Simmer these parts in hot water with a teaspoon of espresso machine cleaning powder for ten to fifteen minutes. For a more thorough clean, or if stubborn residue remains, you can also soak them in a solution like Cafetto Evo.
3. Clean Remaining Residue
   • After soaking, brush off any residing grounds.
   • If there’s stubborn residue, you can also give them a little scrub with a sponge or soft scour and a little dish soap. Rinse them out completely.
   • Wipe clean the dispersion block (if present) and the gasket area where the water comes from inside the group head. Coffee can accumulate in these areas, adding bitterness and harshness to your espresso.
4. Reassemble
   • Once cleaned, reassemble the parts and screw the shower screen back into place.

Additional Tips

• “Finger Test”: The screen and the inside of the basket should pass the “finger test” – you shouldn’t be disgusted by what you find when rubbing your finger inside. If you see significant coffee accumulation, your cleaning schedule may not be frequent enough.
• Puck Screens: Using a puck screen can help reduce the amount of residue that accumulates around the shower screens.
• Gasket and Screen Replacement:
  • Gaskets inside the group head are wear parts and should generally be replaced every year in a domestic setting. They can age, become brittle, and lead to imperfect seals, causing water or coffee to run down the outside of your portafilter.
  • The shower screen itself may also age or its mesh may detach. It’s not an expensive part to change and is worth replacing if it shows significant wear, especially if you pull a lot of shots or use higher doses.

How to clean the steam wand?

Cleaning the steam wand is crucial for both the lifespan of your espresso machine and for safety, as milk residue can build up, leading to bacteria growth and affecting the quality of your microfoam.

Here’s how to clean your steam wand:

Daily/After Each Use Cleaning

This routine maintenance helps prevent milk build-up and avoids the need for more frequent deep cleaning.

• Purge the steam wand for a couple of seconds immediately after steaming milk. This releases any milk inside the wand.
• Wipe the wand thoroughly immediately with a hot, clean, wet cloth. This is essential to remove any milk residue that may stick to the outside.

Deep Cleaning (with Detergent)

Deep cleaning is recommended periodically, for example, around every 6 months for home machines, or whenever you observe an accumulation of dried milk solids around the holes of the steam wand.

There are two primary methods for deep cleaning with detergent:

Method 1: Soaking the Steam Wand Tip (Recommended)

This method focuses on cleaning the part most likely to accumulate stubborn residue.

1. Remove the tip of the steam wand. You might need a small spanner to unscrew it.
2. Soak the removed tip in some hot water and detergent.
3. Crucial Precaution: Always remove the tip for cleaning and avoid soaking the entire wand. Soaking the entire wand, especially if there’s a poor seal, could cause the machine to pull “milky disgusting water” back into its own steam boiler, which is “very bad”.

Method 2: Steaming a Cleaning Solution

This method cleans the internal parts of the wand.

1. Prepare the cleaning solution: Pour some espresso machine cleaning solution (such as Cafetto MFC or Urnex Rinza) into a milk pitcher.
2. Steam the solution: Pop the steam wand into the pitcher and steam the solution for a few seconds. One source also suggests letting it sit for about 30 minutes after putting the wand in.
3. Rinse thoroughly: After using the detergent, you must repeat the process just with warm water to purge any cleaning solution left inside the wand.

How to clean the water tank?

When it comes to maintaining your espresso machine’s water tank, the primary advice from the sources focuses on preventive measures rather than a specific cleaning procedure with detergents.

Here’s what the sources recommend:

• Do not let water sit in your tanks for too long.
• If you have been away, you should change the water in the tank.
• This is important because water can accumulate a biofilm inside the tank, which can negatively affect the taste of your coffee.
• Therefore, turning over the water in your water tanks regularly is a good idea to prevent this buildup.

While the sources emphasise preventing biofilm and ensuring fresh water, they do not provide explicit instructions on how to clean the water tank using cleaning solutions or brushes if a biofilm or other residue has already formed. They discuss using cleaning solutions for backflushing, group head screens, and steam wands, but not specifically for the water tank.

How to clean the drip tray?

Cleaning the drip tray of your espresso machine is a simple, yet important, step in maintaining cleanliness.

To clean the drip tray:

• Remove and empty the drip tray of all coffee grounds.
• Then, wipe it clean with a soft, wet cloth.
• It’s important not to let mould grow in your drip tray.

Clean the external casing of your espresso machine

To clean the external casing of your espresso machine, you should:

• Clean the external casing with a soft, wet cloth.
• Buff it dry with a separate cloth or paper towel.
• Be sure to use a gentle fabric as any abrasive material may cause scratches.

How often should I clean my espresso machine?

Cleaning your espresso machine regularly is crucial for both the taste of your coffee and the longevity of the machine itself. Neglecting cleaning can lead to poor-tasting coffee, often described as bitter or metallic, and can even cause the machine to malfunction.

Here’s a breakdown of how often different parts of your espresso machine should be cleaned:

Overall Machine / Daily Use

For commercial espresso machines, all parts should be cleaned daily. For home users, general routine care and maintenance should be performed to ensure delicious-tasting espresso and a long lifespan for your machine.

Purging the Group Head

A quick 2-second flush should be done after every shot to rinse away grounds and residue from the diffusion screen and prevent buildup. This also helps to drag out residue before it deposits inside the machine.

Purging the Steam Wand

The steam wand should be purged for a couple of seconds immediately after steaming milk to prevent buildup. It should then be wiped thoroughly with a hot, clean, wet cloth immediately to remove any milk residue.

Water Backflushing (with water only)

This can be done weekly or daily for home machines, with more frequent cleanings ensuring tastier shots. For E61 group heads, more frequent water backflushing is recommended to supplement detergent backflushing and prevent premature wear on gaskets.

Drip Tray

The drip tray should be emptied and wiped clean with a soft, wet cloth regularly to prevent mould growth.

Portafilters and Filter Baskets

These should be cleaned at least weekly. After a session of making coffee, it’s good practice to clean them immediately to prevent retained liquid from cooking down and depositing soluble material. They can be soaked in hot water with espresso machine cleaning powder for ten to fifteen minutes every few weeks or overnight for a more thorough clean.

Group Head Screens

For commercial machines, group head shower screens should be cleaned every day. For home machines, the minimum frequency for a regularly used machine is weekly, but there’s no reason not to clean them more frequently if desired. Every few weeks, it’s recommended to remove the diffusion screen and portafilter basket to soak in a cleaning solution like Cafetto Evo.

Detergent Backflushing

For most machines, it is recommended to perform a backflush with detergent every few weeks or so. For commercial machines, backflushing the brew group should be done daily. However, for E61 group heads, it’s recommended to backflush with detergent only every few months or so, as the detergent can cause the gaskets to wear prematurely.

Steam Wand (Deep Cleaning)

Deep cleaning with detergent is recommended around every 6 months for home machines, or when there’s an accumulation of dried milk solids around the holes of the steam wand.

External Casing

The external casing should be cleaned with a soft, wet cloth and buffed dry.

Water Tank

The water in the tank should be turned over regularly and not allowed to sit for too long, especially if you have been away, to prevent biofilm accumulation.

Overall, regular and consistent cleaning habits are key to maintaining your espresso machine and ensuring the best possible coffee quality. It’s also always a good idea to read your machine’s manual for specific cleaning instructions, as processes can vary between manufacturers.