23-05-2025
What's that film inside my electric kettle, and how do I get rid of it?
Q: What is the soft buildup on the bottom of my electric kettle, and what's the best way to remove it?
A: Mineral deposits, also known as limescale, can coat the bottom of an electric kettle with a white or gray film that can seem chalky or crusty, depending on how thick it is. The minerals, typically calcium and magnesium, are left behind when water boils and evaporates because only pure water turns from liquid to the gas we know as steam.
The deposits are inevitable, unless you heat only distilled water in the kettle. With tap water, how quickly the deposits form depends partly on the mineral concentration in the water. Deposits form quickly if you have so-called hard water, which has such a high concentration of minerals that soap doesn't lather well. Deposits also are more of a problem if you use a kettle frequently. How you refill the kettle also matters. If you routinely top off water that's in the kettle, rather than emptying and refilling it each time, you will gradually increase the mineral concentration in the kettle and need to remove deposits more often.
Mineral deposits are easy to ignore, but a thick crust can affect the taste of the water and block heat transfer. If water seems to be taking longer to boil, or if the kettle switches off before water boils, excessive mineral buildup is probably the culprit. Another sign that it's time to deep-clean: If your kettle has a replaceable filter behind the spout that's clogged with grit. The grit is almost certainly bits of the deposits, which you can remove by lifting the filter out and rinsing it in running water. Wipe with a cloth or use a soft brush to dislodge stubborn bits.
KitchenAid, a manufacturer of electric kettles, recommends monthly cleaning to remove deposits, but you can adjust that timing to match what you see or experience. Although it's possible to remove mineral deposits by scrubbing with an abrasive pad, doing that on the inside of a kettle could scratch the interior. It's much safer to use simple chemistry to break the bonds holding the deposits in place. The deposits are usually alkaline, so acids are the way to attack them. You can use a commercial limescale remover, such as Oxo Brew All-Natural Descaling Solution, or try one of several acids you may have on hand (if not, you can buy them in a grocery store).
Suitable cleaners include lemon juice, white vinegar, citric acid and cream of tartar. Advice varies about what concentrations to use and how long to let the solutions soak. And cleaning regimens will depend on the thickness and chemical composition of the deposits. There's considerable wiggle room: Within reason, you can use a more potent concentration or let the solution sit longer. Be aware that you might need to repeat whatever process you choose to get a clean kettle.
White vinegar is probably the most commonly recommended cleaner. Cuisinart says that if you aren't using a commercial descaler, you should pour enough white vinegar into the kettle to cover the base ½ inch deep, then heat the vinegar until it boils. 'Repeat with cool vinegar until all deposits are removed,' then rinse several times. KitchenAid recommends using one part white vinegar to three parts water, enough to cover the deposits. Heat until boiling, then let it sit overnight. Drain, then fill with water alone. Boil and drain. Refill with water and boil a second time, then a third.
Although these instructions differ in details, they all advise repeated rinsing. That's because vinegar has such a strong smell that any remnant can work its way into the first batch or two of tea or coffee you make after cleaning the kettle. Plus, while you're cleaning, the smell can make your kitchen seem like a pickle factory.
If a lemon scent is more appealing, you can switch to a solution recommended by Fill the kettle one-fourth full with lemon juice, then add enough water to make it three-fourths full. Boil, let it cool enough so the water won't burn your skin, then pour out the water and scrub the still-hot interior with a cut piece of lemon. Electric kettles often have a capacity of 1.5 to 1.7 liters, or around 6 to 7 cups, so this solution may require as much as 1½ cups of lemon juice. You might need up to two pounds of lemons (about 10 to 12).
If lemons are too expensive, head over to the store's section for baking ingredients, bulk spices or canning materials and price out citric acid and cream of tartar. Citric acid, a powder that's manufactured by fermenting a type of mold to match an acid found naturally in citrus, is used to adjust the pH of tomatoes and other produce during home canning. It's also used to add tang to recipes. Cream of tartar is made from tartaric acid, a natural by-product of the winemaking process. Among the reasons it shows up in recipes: It keeps whipped egg whites from deflating prematurely. If your grocery store sells spices in bulk, that's probably where you can purchase these powders most economically. Although both have an extremely tart taste, as you'd expect from an acid, they create only a slightly tangy smell, hinting at lemons or vinegar, while cleaning a kettle.
For citric acid, KitchenAid recommends adding one tablespoon to enough water to cover the deposits. Bring it to a boil and pour out, then rinse and dry. Bon Appetit offers a slightly different recipe: Add enough water to cover the deposits, bring to a boil, then stir in a rounded teaspoon to a rounded tablespoon of citric acid, depending on the amount of water. Let sit 10 minutes. Rinse and swirl, and rinse again. If deposits are still visible, repeat this process, but wait longer, even overnight, before you empty and rinse.
For cream of tartar, Hamilton Beach recommends putting ½ teaspoon of the powder into the kettle and adding enough water to fill it halfway. Bring to a boil, let cool, then empty and rinse several times.
Whatever solution you choose, you get the idea: Dilute an acid in water. Use heat and time to make the cleaner work better. Repeat the process if you need to. Rinse well. And next time, don't wait as long to clean so you have less to remove.
Have a problem in your home? Send questions to localliving@ Put 'How To' in the subject line, tell us where you live and try to include a photo.
