Descaling: follow your maker's manual

Descaling is the removal of limescale from the inside of a machine. A descaling agent is the product used to do it, and Wikipedia says such agents are typically acidic compounds¹. Which product, how often and in what steps are all things your maker decides.

Descaling isn't cleaning

Breville says cleaning and descaling are different maintenance processes. A cleaning cycle removes coffee oils and residue from the coffee pathway, while descaling removes mineral buildup from the machine's internal water system². Don't swap one for the other.

How often

Makers answer this in three ways.

When the machine asks. Breville says to complete the recommended descale cycle when prompted, or according to the maintenance instructions for your machine². If your machine has a water hardness setting, Breville says setting it correctly also helps determine when descaling or other maintenance is needed³.

On a calendar. A Breville blog post says to descale every one to three months, depending on how often the machine is used⁴. That's a general blog figure. The manual for your model comes first.

By the water. Decent Espresso ties it to the water. It recommends descaling once per year with a 5% citric acid solution for water between 30 and 120 ppm TDS⁵. With sufficiently soft water, under approximately 30 ppm TDS, it says there's no need to ever descale⁵.

Filters can change the timing too. Breville says replacing the water filter as recommended can help reduce mineral buildup and may reduce how frequently the machine needs to be descaled³.

With what

Use the product your maker names. Breville says to use the recommended descaling solution and follow the complete descale and rinse procedure for your specific model². Decent Espresso asks you not to descale with anything other than citric acid, since it can't guarantee that other agents won't damage the machine's components⁵.

Why the care? Wikipedia says strongly acidic descaling agents are usually corrosive to the eyes and skin, so protection such as rubber gloves is advised¹. Read the safety notes on whatever product you use.

Steam boilers

Wikipedia says descaling steam boilers, such as those in espresso machines, can be difficult. The boilers don't fill completely, and the agent can't reach the top¹. It's another reason to follow a maker's full procedure and not make up your own. Never open the machine or change its parts to get at scale.

Where to check

1. The printed manual for your exact model number.
2. The maker's own support site.
3. The machine's own prompts, lights or settings, if it has them.

Water type and hardness feed into all of this. The manuals page shows how two makers' rules differ.

Different makers disagree on timing and products, so don't copy a schedule from another brand. If the manual doesn't answer your question, ask the maker.