Water: Descaling Your Espresso Machine

Learn how to properly and safely descale your espresso machine.

The basics of making espresso sound simple: push hot water through ground coffee under pressure, and yet espresso machines can be surprisingly complex (see our blog post on how espresso machines work). Because of that people make all kinds of claims about the best way to X and the most efficient way to do Y. While, generally speaking, the prevailing content you'll find is good, we recommend you be wary on one topic—espresso machine descaling. Some simpler items like drip coffee makers or automatic "espresso makers" can be descaled by adding water and a chemical solution to the tank then blasting it through the machine. This is not recommended for the espresso machines Clive carries. Here's why:

Flow Restrictors:

Espresso machines build between 8 and 11 bar of pressure and provide the perfect amount of water flow to create delicious espresso. To make that a reality the machines need to have flow restrictors—tiny holes that slow down the flow of water moving through the system—so that the espresso grounds don't hit a wall of water during the infusion process. Some of these flow restrictors are less than 1mm in diameter. When running a descaling solution through an espresso machine, it is common for partially dissolved chunks of scale build-up to clog these flow restrictors and cause problems in the overall water flow path. 

Delicate Components:

Espresso machines utilize a range of mechanical, electrical, and electromechanical components whose constituent parts often don't hold up well to the chemicals in most descaling solutions. There are also many components that utilize pliable materials like rubber, silicone, teflon, etc. to form water tight seals inside the espresso machine. The high acidity of descaling solution can cause these materials to degrade, swell, or harden, causing both obstructions and leaks.  

Incorrect Doses of Descaler:

Descaling solutions are acid on the PH scale and are meant to dissolve scale built up on the inside of the espresso machine's boilers. What we tend to see is a treatment that is either much too harsh for the machine or not concentrated enough to accomplish the intended goal. Acid at high concentrations can quickly compromise parts like vibratory pumps, electrical sensors, and the machine's various valves. At low concentrations, the acid will only partially dissolve the scale build-up, causing it to migrate from the inside of the boiler to the rest of the espresso machine—the opposite of the intended outcome of descaling.

What Clive Recommends:

We recommend adopting the maxim, "If it ain't broke, don't need to fix it", in regards to descaling. Instead of preventative descaling, verify that your water quality is at a consistent 30-50ppm hardness and your water composition doesn't include high concentrations of scaling minerals. This way you mitigate the amount of scale that is building up inside your machine, or negate it completely. Descaling is not a magic solution to problems that should be evaluated by a qualified technician. If a specific component does need to be descaled to resolve a particular issue, refer to our knowledge base or reach out to our tech team for guidance on best practices for disassembling and cleaning. Only soak 100% metallic parts in descaling solution, in a container separate from the whole system.

Final Words:

Filling your machine's reservoir with a descaling solution and running it through the machine may be a tempting way to make up for using poor quality water, but it's a risky move that may do more harm than good. Even worse, we often see home baristas inadvertently damage their machines by trying to descale a machine that doesn't need to be descaled. The bottom line is that scale can only form when minerals like calcium carbonate are present in water as it evaporates. Your espresso machine will never need to be descaled if you don't fill it with the minerals that cause scale in the first place. Your espresso machine is an investment, invest in it by only using quality water. If that's not enough to make you think twice, keep in mind that running a descaling solution through your espresso machine could affect its warranty coverage. 

As always, if you have any questions about the best way to take care of your machine whether regarding descaling or general use you can always reach out to us at support@clivecoffee.com