How to Descale a Coffee Machine: Full Step-by-Step Guide

Several clear signals tell you it's time: your machine takes noticeably longer to brew than usual; the coffee comes out at a lower temperature than it used to; you're getting a smaller volume of coffee per cycle; the machine makes loud gurgling, hissing, or straining noises during brewing; and most tellingly, your coffee starts tasting bitter, flat, or noticeably different without any change in beans or settings.

Many modern machines (Nespresso, most Keurigs, and some espresso machines) have a dedicated descaling indicator light that turns on automatically—if that light appears, don't delay.

On machines without indicators, I recommend descaling every 2–3 months in hard-water areas and every 4–6 months with softer water.

Most descaling cycles run 20–45 minutes total, including the rinse phases. Drip coffee makers are typically the quickest at 20–30 minutes.

Nespresso machines run a dedicated descaling mode that takes about 20 minutes once you fill the reservoir and start the process. Keurigs take roughly 45–60 minutes because the rinse cycles use many individual brew cycles.

Espresso machines vary by model but usually require a 15–20 minute descaling cycle followed by two to three full water-only flushes. The actual hands-on time is minimal—most of the duration is just waiting while the machine runs its cycle.

Using a properly diluted, purpose-made descaling solution will not damage your machine—it's specifically formulated for this purpose. What can damage machines is using the wrong chemicals (household cleaners, bleach, or undiluted acids), skipping the rinse cycles so residue remains inside the machine, or descaling far too infrequently and allowing severe scale buildup that requires aggressive treatment.

The worst outcome from improper descaling is damaged rubber seals from overly acidic solutions—use manufacturer-recommended products or food-grade citric acid at correct dilutions to avoid this. Actually, the bigger risk is NOT descaling: thick limescale insulates heating elements, causes them to overheat, and eventually leads to premature heating element failure.

After testing dozens of products across 500+ machines, my go-to recommendation is Urnex Dezcal for espresso machines and drip coffee makers—it's citric acid-based, effective, and gentle on seals. For Nespresso machines, Nespresso's own descaler is specifically formulated for their equipment and I recommend sticking with it to maintain warranty coverage.

For Keurig, Keurig's own descaling solution or Impresa descaler both work reliably. If you prefer a DIY option, food-grade citric acid powder (1 tablespoon dissolved in 1 quart of water) is effective, inexpensive, and leaves no flavor residue.

I avoid products with harsh synthetic acids unless dealing with extreme calcification.

Yes, significantly—and this surprises many people who assume taste changes are always about beans or technique. Limescale buildup directly affects brewing temperature because calcified heating elements heat water unevenly and often at lower temperatures than the machine was designed to reach.

Cooler water extracts coffee incompletely, producing flat, thin, under-extracted flavors. Scale deposits on flow paths also alter water pressure and distribution.

In my testing, machines brewed 5–8°C cooler when heavily scaled versus freshly descaled—a temperature difference that dramatically changes extraction efficiency. After descaling a heavily calcified machine, the flavor improvement is often dramatic: brighter, more balanced, better-extracted coffee from the same beans.

The most effective prevention is using filtered or softened water instead of hard tap water. A simple Brita-style pitcher filter removes enough minerals to meaningfully extend descaling intervals. Whole-house water softeners essentially eliminate limescale issues.

BWT water pitchers (popular in the specialty coffee world) specifically filter for coffee brewing and are excellent. After filtering water, the next best prevention is regular descaling before severe buildup occurs—treating scale when it's light takes 20 minutes; treating advanced scale after years of neglect is much harder and sometimes impossible to fully resolve. Empty and dry the water reservoir between uses to prevent stagnant water deposits.

These habits can easily double or triple the time between necessary descaling cycles.

Technically yes—citric acid dissolves calcium carbonate (limescale) effectively. However, Nespresso officially recommends using their own descaling kit and warns that using third-party solutions may void the warranty.

If you're still within the warranty period, stick with the official Nespresso descaler. If you're past warranty and want to use citric acid, dissolve 1 teaspoon (4g) of food-grade citric acid powder in 1 liter of water, then follow the standard Nespresso descaling procedure.

Run at least two full rinse cycles with fresh water afterward. I've used this method on my own out-of-warranty Nespresso Vertuo without any issues, but I wouldn't risk it on a new machine.