Coffee Machine Descaling guide

Descaling removes limescale buildup from inside your coffee machine’s water system.

If you’re in the UK — especially in hard-water areas — this is essential maintenance.

Limescale affects:

• Heating performance
  
• Water flow rate
  
• Extraction quality
  
• Internal components (boilers, thermoblocks, valves, sensors)
  

Ignoring descaling is one of the fastest ways to trigger faults.

Limescale is a chalky mineral deposit left behind when hard water is heated.

It forms inside:

• Boilers
  
• Thermoblocks
  
• Flow meters
  
• Pipes
  
• Steam systems
  

Over time it restricts water movement and causes overheating.

You probably do if:

• Your machine says “Descale”
  
• Coffee is flowing slowly
  
• Steam pressure is weak
  
• The machine is noisier than usual
  
• Temperature feels inconsistent
  
• It takes longer to heat up
  

If you live in a hard water area and don’t use a filter — descaling is essential.

Water Type Frequency

Hard water every 1–2 months

Medium every 2–3 months

Soft every 3–4 months

Using filter Only when prompted
If your machine has a water filter installed, ensure the filter setting is turned ON in the machine menu — otherwise it may prompt unnecessarily.

Use a proper coffee machine descaler.

Avoid:

• Vinegar
  
• Citric acid (unless manufacturer approves)
  
• Random supermarket cleaners
  Why?
  Vinegar can damage seals and leave odours.
  Incorrect chemicals can attack aluminium or brass components.

Step-by-step:

1. Remove water filter (if fitted)
   
2. Empty drip tray and grounds container
   
3. Mix descaler with water as instructed
   
4. Fill water tank with solution
   
5. Start the machine’s Descale Program
   
6. Allow the full cycle to complete (do not interrupt)
   
7. Rinse tank thoroughly
   
8. Run at least 1–2 full tanks of fresh water
   
9. Reinstall new water filter (if using one)
   

Never stop a descale cycle midway — this can lock the machine into “Descale Required”.

Descaling usually runs through:

• Coffee circuit
  
• Steam circuit
  

But it does not clean milk residue.

You must:

• Run a separate milk clean cycle
  
• Or deep clean milk parts manually
  

Descale = mineral removal

Milk clean = hygiene

They are different processes.

1. Mix descaler as instructed
   
2. Run solution through:
   Group head
   Steam wand
   
3. Pause between cycles to allow solution to work
   
4. Empty boiler fully (if machine allows)
   
5. Flush thoroughly with clean water
   

Some dual-boiler or commercial machines require partial disassembly or engineer servicing. Always check manufacturer guidance.

1. Enter descale mode
   
2. Fill tank with descaler solution
   
3. Run full tank through
   
4. Rinse and run clean water cycle
   
5. Reset descale warning
   

Pod machines still build scale — even though they’re simpler internally.

You may experience:

• “Flow Error”
  
• “Heating Error”
  
• “Temp High”
  
• “Pump Running But No Water”
  
• Boiler safety cut-out trips
  
• Burnt taste
  
• Complete machine shutdown
  

Limescale is one of the biggest causes of premature failure.

Many UK regions have moderate to very hard water.

If you’re unsure:

• Check your local water supplier
  
• Use a hardness test strip
  
• Set the hardness level in your machine settings correctly
  

Incorrect hardness settings cause:

• Too frequent descale prompts
  
• Or not enough descaling

Option 1: Use a Water Filter

Most bean-to-cup machines support:

• Tank filters
  
• Brita-style cartridges
  
• Manufacturer-specific filters
  

Replace every 1–2 months (or per litres used).

Option 2: Filtered or Softened Water

Using filtered water significantly reduces descale frequency.

Using vinegar

Using too much descaler

Not rinsing fully afterwards

Forgetting to remove filter before starting

Stopping mid-cycle

Ignoring the descale warning for months

Still says “Descale Required”

• Machine reset not completed
  
• Cycle interrupted
  
• Hardness setting incorrect
  

Water tastes strange

• Not flushed enough afterwards
  
• Run 2–3 more clean water cycles
  

No water after descale

• Air lock in system
  
• Run hot water function repeatedly to re-prime pump

Descaling is not optional maintenance — it protects:

• Boilers
  
• Thermoblocks
  
• Pumps
  
• Solenoid valves
  
• Temperature sensors
  

Regular descaling = longer machine life + better coffee.