How do I descale my coffee machine?

by Paul Sadler

What is scale and why is it a problem?

Scale is a term used to describe mineral build up inside a coffee machine. Scale will build up on all parts of your machine that come into contact with hot water including boilers, heating elements, pumps and brew groups. Scale build up can cause a number of problems. Common problems are reduced boiler heating rate, reduced steam strength and reduced brew water flow rate.

Prevention

Prevention is better than cure. The best way to prevent scale build up in your coffee machine is to use tap water that has been filtered and softened with a professional water filtration system. Learn more about my recommended water filtration systems by clicking here. Tank water and bottled water are other options to consider for scale prevention.

Cure

Most of my customers (9/10) use unfiltered tap water so this means that most of use choose cure instead of prevention. Unfiltered tap water can be used in your Italian coffee machine but all tap water contains minerals that cause scale. This means that your machine will need to be descaled periodically.

DIY descaling

If you decide on a DIY descale only use dedicated coffee machine descaling solution. I recommend Caffetto cleaning products. Do not use citric acid. The reason for this is that dedicated descaling solution will gradually dissolve scale whereas citric acid will dislodge slithers of scale. These slithers can then get pumped through the machine and cause blockages. The risk of scale slithers is the reason that some coffee machine manufacturers do not recommend descaling.

Remember that coffee machine warranties do not cover damage caused by scale build up or damaged caused by scale dislodged during descaling. Descale at your own risk. There are risks to DIY descaling but if you follow my advice you will reduce this risk. If you decide to descale your machine here are the steps to follow.

  1. Turn the machine on and wait for it to heat up.

  2. Fill the water reservoir with descaling solution.

  3. Flush descaling water through the brew group.

    • Single Boiler Coffee Machine: Draws descaling solution from the water reservoir into the boiler and the brew group.

    • Heat Exchanger Coffee Machine: Draws descaling solution from the water reservoir into the heat exchanger and brew group.

    • Dual Boiler Coffee Machine: Draws descaling solution from the water reservoir into the brew boiler and the brew group.

  4. Flush descaling water through the hot water wand.

    1. Single Boiler Coffee Machine: Draws descaling solution from the water reservoir into the wand.

    2. Heat Exchanger Coffee Machine: Draws descaling solution from the water reservoir into the boiler.

    3. Dual Boiler Coffee Machine: Draws descaling solution from the water reservoir into the steam boiler.

  5. Leave for 60 minutes then repeat Steps 3-4.

  6. Fill the water reservoir with tap water.

  7. Flush tap water through the brew group.

    1. Single Boiler Coffee Machine: Draws tap water from the water reservoir into the boiler and the brew group.

    2. Heat Exchanger Coffee Machine: Draws tap water from the water reservoir into the heat exchanger and brew group.

    3. Dual Boiler Coffee Machine: Draws tap water from the water reservoir into the brew boiler and the brew group.

  8. Flush tap water through the hot water wand.

    1. Single Boiler Coffee Machine: Draws tap water from the water reservoir into the wand.

    2. Heat Exchanger Coffee Machine: Draws tap water from the water reservoir into the boiler.

    3. Dual Boiler Coffee Machine: Draws tap water from the water reservoir into the steam boiler.

  9. Dilute the descaling solution by repeating Steps 7-8 several times.

  10. All done. Time to enjoy a coffee.

Professional descaling

If you are uncomfortable with the risk of DIY descaling you should first look at prevention. You can prevent scale build up by using filtered water, rainwater or bottled water. If you can’t prevent the scale from building up and you don’t want to try out DIY descaling you can take your machine to a coffee machine technician periodically for professional descaling and servicing.

Descaling Frequency

Descaling frequency will depend upon the quality of your tap water quality and the amount of water that runs through your machine.

There’s no one answer here but here’s a rough guide for an Italian coffee machine running unfiltered Melbourne tap water. If you choose the DIY approach it is important that you descale regularly, before thick scale can build up. An annual DIY descale should do the trick. If you choose the professional descaling approach a professional descale every 5 years or so should be all that you need to keep your machine healthy.

Note - Italian coffee machine warranties do not cover damage caused by scale

K Bean Coffee 18 B BEAUMARIS Australia