July 27, 2021

Cleaning your coffee brewer at home

The quality of home-brewed coffee depends on a huge number of different factors, from the consistency of your grind to the temperature of your water. But one often-overlooked factor is how clean your coffee brewer is. 

Look up how to clean any specific coffee brewing method online, and you’ll get a number of different results. In some cases (such as with the moka pot), people may even argue that they don’t need to be cleaned. But urban myths or misinformation can affect the flavour of your brew, the lifespan of your equipment, and even your health if you’re not careful.

So, to learn more and debunk some common cleaning myths, I spoke to two SCA-certified specialists. They told me more about the correct cleaning and maintenance practices for a range of different brewers. Read on to find out what they said.

You may also like our article on keeping your coffee shop clean and safe.

moka pot

Misinformation & urban myths: Should you clean your moka pot?

There’s a long-held urban myth (supposedly Italian in origin) that states that you should never clean your moka pot. Some say that cleaning it ruins the flavour of the coffee, while others say that years’ worth of residue inside the brewer “improves” the flavour.

But most conventional moka pots are made of aluminium – which can become a health hazard if not cleaned correctly.

Davide Cobelli is a coffee consultant, SCAE official trainer, and the owner of Garage Coffee Bros and the Coffee Training Academy in Verona, Italy. According to him, these moka pot myths are widely ingrained.

In Italy, the moka pot is commonly used by homebrewers to make thick, intense coffee. Davide explains that the intense flavours and bitterness that Italian consumers associate with a “dirty moka” reflect the ideal characteristics of a Neapolitan roast. 

He says: “It is quite common in Italian households to find moka pots that haven’t been cleaned with anything but water for around 20 years.”

The old, residual coffee particles release their acids when exposed to hot water. When not properly cleaned, these particles can cause the aluminium to corrode over time and release metals into the coffee.

Edwin Harrison is the owner of Artisan Coffee and Artisan Coffee School in London. He agrees with Davide. “Seasoning a moka pot will create bitter and rancid coffee,” he says. “It should be cleaned as thoroughly as any other coffee brewing equipment.”

He says that because aluminum is porous, coffee compounds attach to these pores and become very difficult to remove. Corrosion then compounds this issue.

french press

Cleaning different types of brewers

So, we know that your moka pot needs to be cleaned regularly, or else it can become a health hazard that only produces “rancid coffee”, as Edwin says. But the same is also true of many other different coffee brewing methods, from your AeroPress to your espresso machine.

To help, we’ve put together some guidance for how you should care for a few popular coffee brewers, starting with the moka pot.

Moka pot

David and Edwin agree that the best way to clean a moka pot is by using a neutral, fragrance-free dish soap and a soft sponge. 

Edin says that it’s important to dismantle the brewer first, before scrubbing it gently, both inside and out, and rinsing every part thoroughly to ensure there is no soap residue.

Edwin says: “All the pieces of the pot should be completely dry before reassembling them, to avoid a build-up of mildew or condensation.”

The moka pot gasket seal is also commonly overlooked in the maintenance process. This is the circular seal that sits between the two halves of the pot. Edwin says that it should be changed semi-regularly, particularly when you’re unable to get rid of any brownish stains. 

You can also change the aluminium filter basket, too. If this gets clogged over time, just replace it. They’re widely available online, as are replacement gasket seals.

What you definitely should not do, says David, is simply clean the moka pot with a damp cloth or rinse it with water. You should also avoid using a dishwasher or vinegar and lemon juice, as these can cause corrosion.

French press

Start by removing the coffee grounds using a spatula or add some water and swirl. Toss the grounds into the bin (or your compost heap) and clean out any loose grains.

Fill the jug halfway with warm water and a few drops of fragrance-free dish soap. Pump the plunger through the water several times several times to dislodge any stubborn grounds caught in the filter.

Clean the jug by hand, using hot water and a soft sponge or bottle brush. Rinse both parts well, making sure there is no soap residue. Dry immediately using a microfibre cloth.

For heavy users, it’s recommended that you clean the filter thoroughly at least once a month. For this, disassemble the filter (you can usually unscrew it by hand) and make a simple paste using baking soda and water. 

Scrub the filter mesh vigorously with a toothbrush or bottlebrush to remove any oils and residue, before rinsing and cleaning with soap and water.

Batch brew

Remove the server, pot (or urn), and filter basket. Clean both thoroughly with a sponge and some fragrance-free dish soap, then rinse well. Air dry or use a clean microfiber cloth.

While the remainder is drying, wipe the brewer head with a damp cloth to ensure there are no odd coffee grounds or stains. Only reassemble the brewer once every part is completely dry to avoid risk of mold.

aeropress and hand

AeroPress 

After brewing, press down on your puck over the sink to squeeze out any remaining liquid. After this, move to the bin (or compost heap) and unscrew the filter cap. Press the plunger down until the puck pops out.

After this, disassemble the brewer and wash each individual piece with hand using a soft sponge and fragrance-free dish soap. Air dry or use a clean microfibre cloth.

About once a month, you should remove the rubber seal from the plunger entirely to clean it. Scrub it inside and out to remove any oil buildup. 

Pour over drippers

Most pour over coffee drippers can be cleaned reasonably simply. Use a neutral dish soap and a sponge to scrub the inside and outside, rinse clean and dry.

How you clean your server (if you use one) will depend on the material. For glass or clear plastic servers, you may be able to use a dishwasher (check manufacturer guidance). If not, or if you’re using a metal server, you will need to be more thorough. 

Try using a cloth with some dish soap and warm water. You may not be able to fit your hand through the opening, so a brush may be easier.

Home espresso machine

To start with, Edwin suggests that you follow the manufacturer’s cleaning instructions thoroughly. Each machine has its own requirements, but simply using the auto-clean and descaling functions won’t be enough after a prolonged period od regular use.

He says: “After pulling a shot, remove the portafilter and immediately flush (purge) the group head for a couple of seconds. This will release any coffee that may have attached itself to the diffusion screen.

“For cleaning a steam arm after steaming milk, carefully wipe it with a damp cloth.  Then, activate the steamer’s jet for a few seconds to purge any left-over milk. 

“Finally, remove the portafilter basket [and rinse with hot water to] remove all the coffee oils and residues. Dry with a microfiber cloth.”

Next, he says, you need to turn on the pump and scrub the diffusion screen with a toothbrush or a Pallo brush. Backflush it using a blind portafilter and a quarter-teaspoon of an espresso machine cleaning powder of your choice. Allow the pump to flow for at least five seconds, then repeat several times.

Empty the water from the blind portafilter and repeat once with no powder to clear any remaining chemicals. Empty the drip tray, rinse with hot water, and dry it with a microfibre cloth. Finally, once everything is dry, reassemble all the pieces. 

For the exterior, Edwin’s pro tip is to use a glass cleaning product to keep the machine’s stainless steel surfaces “looking as good as new”.

coffee machine steam wand

Getting rid of limescale

Limescale is a sediment found in hard water (water with high levels of calcium and magnesium) that builds up in brewing equipment and kettles. It can cause damage to your brewer if left unchecked.

For kettles and batch brewers, Edwin says a solution of one part vinegar to one part water is enough to clean limescale. 

For a kettle, he says to let the solution soak overnight, then rinse the equipment thoroughly. Boil a full tank of water a couple of times afterwards just to clear it out.

For a batch brewer, he says to fill the tank with the solution and let the cycle run through two or three times. Then repeat the process with fresh water a few more times.

However, he also notes that prevention is better than the cure. Limescale can generally be prevented by brewing with filtered mineral water or distilled water.

He says: “Espresso machines have instructions on how to deal with limescale, but in this instance, prevention is by far the economic solution, because you might [eventually] need to pay a technician to descale your machine.”

coffee cup on the ground

Can improper cleaning be bad for you?

Correct cleaning procedures are vital for home brewing, but it’s not just about safeguarding the longevity of your equipment or compromising taste – improper cleaning can also be a serious health hazard.

According to Edwin, the biggest mistake people make is not cleaning devices soon enough.

He says: “A lot of people forget that coffee is a food product and, if the equipment is not properly looked after, it will eventually stop working properly and can make you seriously ill.”

For instance, he notes that letting spent grounds sit in the equipment until you are ready to make your next coffee is a really bad habit. The oils in coffee build up and create a “film”, which is then a perfect environment for bacteria to grow.

And while it’s widely believed that the acidity of roasted coffee is enough to kill most of these germs, it is not always enough on its own. Along with allergies and respiratory infections, the bacteria that form on this film can also affect your digestive health.

To put things in perspective, a 2011 study by NSF International found that an unclean coffee maker’s reservoir can host more bacteria than pet toys and the flush handle on your toilet. 

collection of coffee brewers

“There is no such thing as ‘self-cleaning’ coffee equipment,” Edwin concludes. Good cleaning practices for coffee brewers should ultimately not be taken lightly.

To make sure you remain healthy and get the best possible flavour from each cup of coffee you brew, make sure you’re cleaning your brewer properly. It will also maximise the lifespan of your equipment.

Enjoyed this? Then read this article on how and when to clean your coffee roaster.

Photo credits: Pixabay, Pexels

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