Coffee Machine Cleaning and Maintenance

Cleaning and Maintenance of Coffee Machines – Complete Guide

A coffee machine is an investment that, with proper care, will reward you with years of reliable performance and excellent taste in every cup. Neglecting cleaning, on the other hand, leads to gradual degradation of flavor, reduced performance, and in extreme cases, costly repairs. At pestik.cz you'll find everything you need for cleaning and maintenance of coffee equipment.

Why is cleaning a coffee machine so important?

During coffee preparation, three types of contaminants gradually accumulate in the machine, each with a different impact on taste and machine lifespan and requiring a different approach:

Coffee oils and residue

Coffee beans contain 10–15% oils that are released during extraction and settle on all surfaces in contact with coffee – in the portafilter, shower head, group head, and internal hoses. Oils go rancid quickly and give coffee an unpleasant bitter, even pungent aftertaste. If your coffee has inexplicably become bitter, old coffee residue is the first suspect.

Scale (mineral deposits)

Hard water contains dissolved minerals – primarily calcium and magnesium carbonate – which precipitate on the walls of hoses, heat exchangers, and valves when heated. Scale reduces water temperature, slows flow, strains the pump, and increases energy consumption. A neglected coffee machine can lose up to 30% of its thermal efficiency.

Bacteria and mold

The wet internal environment of a coffee machine is favorable for microbial growth, especially in the water tank, drip tray, and on rubber seals. Regular cleaning and thorough drying of these parts is not just a matter of taste, but also hygiene.

Daily cleaning – the foundation of good practice

A daily routine takes only 5–10 minutes, yet it has a crucial impact on flavor consistency and overall machine lifespan.

After each preparation

Rinse the portafilter – after knocking out the coffee puck, run the portafilter under hot water and wipe with a clean cloth. Wet coffee residue will go rancid within hours.
Purge – run hot water through the shower head without the portafilter for 2–3 seconds. This removes ground coffee particles trapped in the group head.
Wipe the steam wand – immediately after steaming milk, wipe the wand with a damp cloth and purge briefly with steam to dislodge milk residue from inside. Dried milk proteins are remarkably stubborn.

At the end of the day

Backflush with clean water – on machines with a three-way solenoid valve, perform a backflush without any cleaning agent
Clean the drip tray – empty and rinse to prevent odor and mold
Empty the water tank – stagnant water is a breeding ground for bacteria; if you don't use the machine overnight, remove the tank and let it dry

Backflush – how to do it

Backflush is a process where water under pressure is forced back through the shower head and three-way valve, flushing out coffee residue from otherwise inaccessible places. It only works on machines equipped with a three-way solenoid valve (most lever machines).

Insert a blind basket (blind basket) into the portafilter
Attach the portafilter to the group head
Run the extraction for 10 seconds
Stop for 10 seconds – water will reverse through the valve and dislodge residue
Repeat 5–6 cycles
Remove the portafilter and rinse thoroughly

Weekly cleaning – deep intervention

Once a week, perform a more thorough cleaning using cleaning agents specifically designed for coffee machines. This frequency is appropriate for home use; in commercial settings, chemical backflush is recommended daily.

Chemical backflush

Insert a blind basket into the portafilter
Sprinkle 2–3 g of cleaning agent (Cafiza, Puly Caff, or comparable product)
Perform 5 backflush cycles (10 seconds on, 10 seconds off)
Let the solution sit in the group head for 5–10 minutes – the alkaline agent needs time to break down coffee oils
Perform 5–6 backflush cycles with clean water
Prepare and dispose of 2–3 "waste" coffees until the water runs clear and odor-free

Soaking the portafilter and baskets

Dissolve the cleaning agent in hot water according to manufacturer's instructions
Submerge the portafilter, baskets, and shower head – never submerge the entire portafilter with a wooden or plastic handle
Let soak for 15–30 minutes
Scrub all parts with a brush, paying special attention to the holes in the basket
Rinse thoroughly with clean water and let air dry

Cleaning the grinder

Clean the bean hopper with a dry cloth – coffee oils settle here too
Run cleaning granules (e.g., Grindz) through the grinder according to manufacturer's instructions
Immediately after the granules, grind a small amount of coffee to remove any traces of the cleaning agent
Use a brush to clean the outlet and the area around the burrs

Descaling – fighting scale

Descalers are an essential part of maintaining any coffee machine that uses tap water. The frequency of descaling depends on the hardness of your water and intensity of use.

How often to descale?

Water hardness	Descaling frequency
Soft (below 7 °dH)	Every 6 months
Medium hard (7–14 °dH)	Every 3 months
Hard (14–21 °dH)	Every 6–8 weeks
Very hard (above 21 °dH)	Every month

You can determine water hardness using a test strip (usually included with the machine), on your water utility's website, or with a simple laboratory water test.

Descaling procedure (general)

Empty the water tank and remove any filter
Prepare a descaling solution according to instructions – maintain the exact ratio of descaler to water
Fill the tank with the solution
Run the descaling cycle (if your machine has one) or manually run the solution through the group head and steam wand in stages
Let the solution sit in the system as recommended by the product manufacturer – acids need time to chemically dissolve the scale
Rinse with at least two full tanks of clean water
Prepare and dispose of the first coffee after descaling

Types of descalers

Citric acid – a natural and affordable option. Use 20–30 g per liter of water. It's gentle on seals and metal components and easily available at any pharmacy.

Specialized descalers – formulated specifically for coffee machines; contain corrosion inhibitors and additives that protect rubber seals. They're more expensive, but a safer and more reliable choice for higher-end machines.

Vinegar – we don't recommend it. Aggressive acetic acid can gradually degrade seals and leaves a persistent odor and taste that are difficult to remove even after repeated rinsing.

Portafilters and seals – replacement parts

Portafilters and seals are components that gradually wear with regular use and require planned replacement.

Portafilter

The portafilter lever itself has a practically unlimited lifespan if made from quality material – brass with chrome plating or stainless steel. The baskets inside, however, wear and their holes enlarge, disrupting extraction evenness:

Standard baskets – inspect every 6–12 months; replace when you notice visible wear or enlarged holes
Precision baskets (VST, IMS) – a more expensive alternative with laser-drilled holes; ensure more even flow and significantly longer lifespan

Group seal

The rubber seal between the group head and portafilter gradually hardens, shrinks, and stops sealing properly. Characteristic signs of wear include:

Water leaking around the portafilter during extraction
Need for more force when inserting or rotating the portafilter
Visible cracking, deformation, or hardening of the seal

The group seal should be replaced every 6–12 months with daily use. It's a simple home task – just pry out the worn seal with a flathead screwdriver, thoroughly clean the groove, and insert a new seal of the correct size.

Shower screen

The shower screen ensures even water distribution across the coffee puck. Over time it becomes clogged with coffee residue and minerals, causing uneven extraction and channeling. Unscrew it monthly, soak it in cleaning solution, and carefully scrub with a brush. If you notice visible damage, deformation of the holes, or corrosion, don't hesitate to replace it.

Maintenance plan – clear schedule

Daily

Rinse portafilter after each use
Purge shower head
Clean steam wand after steaming milk
Backflush with clean water at end of day
Empty drip tray

Weekly

Chemical backflush with cleaning agent
Soak portafilter, baskets, and shower head
Clean water tank
Clean grinder with brush

Monthly

Disassemble and thoroughly clean shower screen
Clean grinder with cleaning granules
Visual inspection of seals and hose connections

Quarterly

Descaling (adjust frequency to your water hardness)
Check and possibly replace group seal
Check for wear on portafilter baskets

Annually

Professional service – especially recommended for mid-range and higher-end machines
Replace group seal and possibly other rubber parts
Check pump pressure and safety valve function

Frequently asked questions

Can I use regular dishwashing liquid to clean a coffee machine?

No. Dishwashing liquids contain fragrances, softeners, and surfactants that settle on internal surfaces and penetrate into the coffee's taste. Use only cleaning agents specifically designed for coffee machines – they're formulated to effectively break down coffee oils without leaving residue or odor.

How do I know if a coffee machine needs descaling?

Warning signs include slower water flow, lower espresso temperature, louder or irregular pump operation, weaker steam pressure, and in advanced cases, dripping or blockage. Most modern machines have a descaling indicator. Still, we recommend not waiting for symptoms and following a preventive schedule based on your water hardness – this prevents damage that's difficult to repair.

Is soft or hard water better for making coffee?

Neither extreme is ideal. Water that's too soft (below 3 °dH) leads to under-extraction and a flat cup without body, as minerals actively help dissolve flavor compounds. Water that's too hard (above 14 °dH) clogs the machine and produces a dull, chalky cup with suppressed acidity. The optimal range is 4–8 °dH with a balanced ratio of calcium and magnesium. A complete selection of water treatment products is available at pestik.cz.

How often should I replace the portafilter?

The portafilter lever itself practically never wears and with standard care will last decades. Replace the baskets inside approximately once every 1–2 years with home use, sooner if you notice uneven extraction or channeling. The group seal – the rubber part where it meets the group head – should be replaced about every 6–12 months. Quality portafilters and seals are available at pestik.cz.