What Is Coffee Descaler and How Often Do You Need to Use It?

updated Jun 10, 2021
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someone is pouring descaler into a coffee maker
Credit: Photo: Joe Lingeman; Food Styling: Anna Stockwell

Coffee definitely helps us all scale mountains. (Figuratively … probably.) But there’s another kind of coffee-related scale we need to talk about: The white or gray crud that builds up inside your auto-drip, pod-brewer, espresso machine, and kettle. (See what I did there? Sorry, I’m a coffee expert and we love our coffee jokes!) It can make your brew taste sour and under-extracted — and potentially damage your equipment.

What Is Mineral Scale?

Great question, thanks for asking! Scale is what’s left behind after boiling any non-distilled water. See, all water has some amount of minerals in it (calcium, magnesium, etc.), and they get left behind in small quantities every time water boils. After many, many boiling sessions, those deposits become limescale, which hardens and sticks on things like the boiler, temperature gauges, spray head, and the inside of your trusty carafe. If you live somewhere with particularly hard water, this process will probably happen a bit faster. And, unfortunately, using distilled water won’t solve the problem — in fact, distilled water might ruin your machine completely, as most machine rely on some mineral content in order to function properly.

If the scale builds up enough, it can really damage your equipment’s ability to accurately gauge temperature (the scale can coat the thermometer), water level (it can cling to a probe in a tank), and even its water delivery (if it clogs up the holes in your brewer’s spray head). 

How to Descale a Coffee Maker

Many people think because “water is clean” there’s no need to do anything but give your coffee pot or kettle a quick rinse in order to keep it going. However, to remove scale you have to descale it.

Thankfully, this is easy and pretty inexpensive. You’ve got options, too. One is to buy a descaling product that’s made specifically for coffee makers, like Urnex, Halefresh Descaling Solution, or Impresa, which all come with instructions on how to use them.

Your other option is to pick up a bag of citric acid powder, which can be found at grocery and home-improvement stores, as well as abundantly online. Dilute the citric acid with hot water and let your gear soak in it for a while, then give everything a rinse. (The cleaner-to-water ratio varies, but for a heavy load I like a soaking solution of 1 tablespoon of citric acid powder per quart of hot water.) After you’ve cleaned the filter basket and the carafe, assemble the coffee maker and pour the citric acid mixture into the machine’s water reservoir and let it run through a brew cycle. After brewing, discard the water in the carafe, pour clean water into the water reservoir, and run the machine through a brew cycle once again.

I’d like to note that I personally do not like descaling with vinegar: While it’s an effective and cheap cleaning agent, it can also make your coffee taste like it was brewed in a pickle factory. 

Credit: Joe Lingeman

How Often Should You Descale Your Coffee Maker?

It depends on how much minerality your water has, but I suggest a biannual cleaning at minimum. If you drink lots of coffee (I certainly do), once a quarter might be more appropriate. As soon as you notice a white film on any of your equipment, it’s time to descale. Some coffee manufacturers even recommend descaling after you’ve gone through an entire pack of filters (which is usually 100 per box). But, hey, as long as you remember to descale at some point, that’s something!

Do you have a question about descaling? Let us know in the comments!