Citric Acid Passivation and Descale

Boiler Care

Descaling with Citric Acid

The boiler and all water-contact parts of the Argos can develop scale build-up over time, depending on the hardness of your brew water. To maintain peak performance and prevent issues such as leaks at the steam manifold, we recommend a simple, food-grade descaling treatment that also doubles as a passivation method (increasing corrosion resistance)

Solution:

• Mix 1 part citric acid powder with 10 parts water.

Steps:

1. Fill the boiler with the citric acid solution.
2. Heat the machine - Screw on the boiler cap and bring the machine up to temperature.
3. Let the solution sit in the boiler for 15–20 minutes.
4. Run the solution through the grouphead a few times.
5. Once the boiler is empty, allow the machine to cool. (You can open the steam wand to speed this up.)
6. Rinse the boiler with clean water - empty by carefully tipping the machine upside down over a sink. Repeat several times to rinse thoroughly.
7. Final flush - Refill the boiler, heat the water, and run fresh clean water through the grouphead.

This method helps chemically convert the outer layer of stainless steel, removing free irons that could otherwise lead to rust. Citric acid can be purchased easily online (e.g., Amazon).

Repairing and Preventing Corrosion

The manufacturing process may leave microscopic burrs that can become starting points for corrosion. Use a green scuffing pad or 800+ grit sandpaper to gently remove these marks without damaging the stainless steel.

We also recommend passivation using the same citric acid treatment mentioned above

Solution:

• Mix 1 part citric acid powder with 10 parts water

Steps:

1. Heat the solution in a pot.
2. Submerge the stainless steel part fully.
3. Leave for 15–20 minutes.
4. Rinse thoroughly.