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To descale a milk frother, fill it with a warm citric acid solution mixed per the descaler's label, let it sit 20 to 30 minutes without running the whisk, then rinse two or three times with fresh water. That handles electric jug frothers, the kind with a heating plate in the base, which are the only frothers that scale meaningfully. Scale is a water problem, not a milk problem: it is the white mineral crust left where hard water is heated, and it builds on the frother's heating surface every time you rinse the jug and leave it wet. Milk residue is a separate deposit that needs a separate treatment, covered below. Your manual's dilution and dwell time win over any generic ratio, so match yours if it gives one.
Which frothers scale, and where
| Frother type | Where scale forms | How to descale |
|---|---|---|
| Electric jug (heats milk) | Heating plate at the bottom of the jug | Warm citric acid soak in the jug, 20 to 30 minutes, rinse well |
| Steam wand on an espresso machine | Inside the boiler and steam path, not the wand tip | The machine's own descale cycle; the wand cannot be descaled separately |
| Handheld battery whisk | Almost nowhere (nothing is heated) | No descaling needed; rinse the whisk head after use |
| Induction frothers with removable jug | Jug base and temperature sensor area | Same citric soak; keep the base unit itself dry |
The chemistry is the same in every case: scale is calcium carbonate, and a mild acid dissolves it back into solution. Citric acid is the standard choice because it rinses clean without lingering odor (citric acid descaler). Vinegar works chemically but leaves a smell that takes extra rinses to clear from a milk vessel, which is the last place you want it. How fast scale builds depends on your water; the USGS calls anything above 121 mg/L of calcium carbonate hard (USGS water hardness), and on hard water a daily-use jug frother shows crust in a month or two.
The step-by-step for a jug frother
Unplug the frother and remove the whisk. Mix the descaling solution with warm water per its label, fill to the max milk line, and let it sit. Do not run a frothing cycle with descaler in the jug unless your manual says to; soaking does the work and keeps acid away from the lid seals. After the soak, wipe the heating plate with a soft cloth, never anything abrasive, because most plates are non-stick coated and a scratch there burns milk forever after. Rinse until the water runs clear and has no smell, then run one plain-water heat cycle and dump it. If the crust survives round one, repeat with a fresh soak rather than a stronger mix.
Scale vs milk stone: two deposits, two fixes
If the deposit is beige or yellowish film rather than white grit, that is milk stone, a protein and mineral layer from the milk side. Acid alone does not clear it well; it needs a detergent or an alkaline milk-system cleaner first, then the descale. The reliable order for a neglected frother is: wash with dish detergent, then descale, then rinse. Steam wand users have the same split: milk cleaner through the wand, descaler through the machine, as covered in the steam wand cleaning guide and descaling vs cleaning.
Related reading
FAQ
How do I descale an electric milk frother? Unplug it, remove the whisk, fill with warm citric acid solution mixed per the descaler's label, soak 20 to 30 minutes, wipe the heating plate with a soft cloth, and rinse until there is no smell. Run one plain-water cycle before frothing milk again.
Can I use vinegar to descale a milk frother? Chemically yes, but it is a poor fit for a milk vessel because the smell lingers and takes extra rinses to clear. Citric acid descaler does the same job and rinses clean.
How often does a milk frother need descaling? On hard water with daily use, every 1 to 2 months; on soft or filtered water, a few times a year. White crust on the heating plate means it is due now regardless of the calendar.
Hardness classes per the USGS Water Science School page linked above. Dilutions and dwell times are general chemistry; your frother's manual overrides them.
Never miss a cycle: the free one-page Machine Maintenance Calendar (PDF) puts every daily, monthly, quarterly, and yearly task for espresso machines, drip, Keurig, and moka pots on a card you can tape inside a cabinet.
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