Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Limescale is the chalky white crust that grows on the bottom of a kettle in a hard water area. It slows the boil, raises the energy the kettle uses, and eventually flakes into the tea. Getting it out is easy and cheap: an acid dissolves it, and the acid is usually white vinegar or a shop-bought descaler. Most of the hour this takes is waiting.
The hard part is not the method, it is the number. Search for a kettle vinegar ratio and you will find one, confidently stated, with no kettle attached to it. We read what five manufacturers actually publish, and they do not agree — not on the strength of the solution, and not even on whether you are allowed to boil it. Breville and Fellow boil the vinegar, De'Longhi tells you to catch the switch just before the boil, and Smeg boils plain water first and adds the vinegar afterwards so that it never boils at all. Dualit names a proprietary descaler and no home remedy, while De'Longhi warns that a proprietary descaler can mark the finish of a kettle.
This page prints none of those as a house figure, because there is no house figure to print. It tells you which questions to take to your own documentation, and what each of the five manufacturers actually said.
DO NOT PUT THE KETTLE BASE, THE POWER BASE OR THE POWER CORD IN WATER.
Water in these parts can cause an electric shock.
| Item | Note |
|---|---|
| Measuring jug | A jug shows the quantity of water that your documentation gives. |
| Soft cloth | Use a soft cloth on the outside of the kettle. |
| Soft brush optional | A soft brush cleans the limescale filter. |
| Descaling agent material | Only the agent in the documentation for your kettle is correct. |
| Clean water material | Water with less mineral content makes less limescale. |
Estimated 7 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
READ THE DOCUMENTATION BEFORE YOU SELECT A DESCALING AGENT.
An incorrect agent can cause damage to your kettle.
KEEP THE DESCALING AGENT AWAY FROM CHILDREN AND ANIMALS.
The agent is an acid and can cause an injury.
Estimated 1 min
Estimated 40 min to 10 hr 15 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
DO NOT OPEN THE LID WHEN THE KETTLE IS ON.
Steam and hot water can burn your skin.
DO NOT KEEP THE SOLUTION IN THE KETTLE FOR MORE TIME THAN YOUR DOCUMENTATION GIVES.
The acid can cause damage to the kettle.
LET THE KETTLE BECOME COOL BEFORE YOU EMPTY THE SOLUTION.
Hot liquid can burn your skin.
Estimated 11 min to 16 min
DO THE RINSE CYCLE AGAIN UNTIL THE WATER HAS NO SMELL OF THE AGENT.
Some agent stays in the kettle and gives a bad taste to the first drink.
Estimated 4 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
DO NOT USE AN ABRASIVE MATERIAL ON THE KETTLE.
An abrasive material can cause damage to the kettle.
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
Do not use a descaling agent that the documentation for your kettle does not name. De'Longhi gives a warning that a proprietary descaler can cause damage to the finish of a kettle.
Stop if water comes through the body of the kettle or through the base. Disconnect the kettle from the power supply. Speak to the manufacturer.
Stop if the kettle does not stop after the water boils. Disconnect the kettle from the power supply. This fault is not a limescale fault. Speak to the manufacturer.
Do not open the body of the kettle. Do not do work on the element in the base. Only a qualified technician must do work in a kettle.
Four of the five manufacturers we read say yes, and the fifth simply does not mention it. Smeg, De'Longhi, Breville and Fellow all publish a white vinegar method for their own kettles. Dualit publishes no home remedy at all and points you at a proprietary descaler instead, telling you that whatever solution you choose must be suitable for the appliance. So vinegar is not the forbidden thing the internet sometimes makes it out to be, but it is also not universally blessed. The one thing none of them says is that a ratio from another brand's kettle is safe in yours.
There is no general answer and this page deliberately prints no figure of its own. Breville and De'Longhi both give one part vinegar to two parts water. Fellow gives half and half, which is noticeably stronger. Smeg does not give a ratio at all: it gives a litre of water in a KLF03 or KLF04 and then somewhere between 100 and 500 ml of vinegar depending on how much scale there is. Those are four different strengths for four different kettles, so the honest instruction is to read your own manual rather than to copy a number off a page like this one.
This is the part that usually gets lost when the ratio is copied around, and it is the one where the manufacturers flatly contradict each other. Breville boils the vinegar solution and then leaves it standing overnight, and Fellow also brings the mixture to a boil. De'Longhi says the opposite, telling you to switch off just before the boiling point. Smeg sidesteps it entirely by boiling plain water first and adding the vinegar to the hot water afterwards, so the vinegar never boils. Boiling an acid and not boiling it are not two versions of the same instruction, and we are not going to split the difference for you.
It depends on your water, and the manufacturers answer in two different ways. De'Longhi and Fellow both give a calendar: about monthly in a hard water area, and every two to three months where the water is soft. Dualit gives a rule of thumb of at least once a month. Smeg gives no calendar and tells you to look at the base of the kettle instead and descale whenever scale appears there. If you are in a hard water area the visual test is the more honest one, because your water does not care what month it is.
It is limescale — calcium and magnesium that were dissolved in your water supply and got left behind when the water boiled off. Dualit states plainly that limescale builds up naturally and is harmless to drink, so the flakes in your tea are unpleasant rather than dangerous. The damage it does is to the kettle: Dualit describes deposits blocking working parts and preventing efficient heating, which is why a scaled kettle takes longer and uses more energy. That is the reason to remove it, not your health.
Breville addresses this directly for its own kettles: it states that the concealed element in the base is stainless steel and that brown staining is mineral deposit rather than rust. That is a statement about a Breville kettle and we are not going to extend it to every kettle ever made, but discolouration on a stainless base is far more often scale and mineral staining than corrosion. Descaling normally shifts it. If it does not, and the metal is pitted or flaking rather than stained, that is worth a call to the manufacturer.
Not necessarily, but read your own documentation before you decide, because the manufacturers genuinely disagree here. Dualit recommends a specific proprietary descaler for its kettles and says any alternative must be suitable for the appliance. Breville names its own kettle cleaner or a proprietary descaler from a shop. De'Longhi points the other way and warns that care should be taken with proprietary kettle descaler because it could damage the surface finish. If your kettle has a painted, matt or metallic finish, that warning is the one to weigh.
Fellow publishes a citric acid method for its kettles and actually prefers it to vinegar, on the grounds that it is a bit stronger and does not leave a lingering smell behind. That is one manufacturer speaking about its own kettles. None of the other four we read publishes a lemon juice or citric acid quantity for a kettle, so if yours is not a Fellow, this is a question for your own documentation rather than something to work out from a fruit. Whatever acid you use, the rinsing at the end matters more than the choice.
Use your nose. Smeg tells you to fill, boil and empty at least twice after descaling, and De'Longhi gives essentially the same thing — boil, empty and repeat once more. Treat two full cycles as the floor rather than the target, and keep going until there is no smell of vinegar or descaler in the water. Then make one drink and pour it away. If that drink tastes wrong, rinse again.
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
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