Why Do All My Electric Kettles Boil Over?

December 7, 2023 11:52 AM

I drink 4 liters of tea daily, so my basic electric kettle gets a workout. Every kettle I’ve had fails by boiling over — uncontrollably spouting very hot water over my counter. I’ve searched for possible culprits, and I think I’m doing all the right things:

Carbon filtering the kitchen cold tap for our local hard water

Always at least half-full

Descale weekly with white vinegar

Scrub off visible scale every morning with dish brush

I’ve tried various US brands (Aroma, Black & Decker, Capresso, Hamilton Beach) and various designs (metal, plastic, glass). I’ve avoided the goose neck (harder to clean) and thermostats (I just need 212° water). They all boil over within 2 years (some within 2 months). I do plug every kettle into the same outlet on my kitchen counter. If there was an electrical issue, wouldn’t it show up right away?

posted by Jesse the K to Home & Garden (18 answers total)

Sounds to me like you could be over-filling your kettle?

I have a wonderful Krups electric kettle that has different temps for different kinds of tea. I usually set it to stop at 175F to 185F rather than actually boiling it. That's better for the kinds of teas I drink, and it also means it never boils over. So maybe turn off your kettle right before it boils?
posted by acridrabbit at 11:58 AM on December 7, 2023 [10 favorites]

Always at least half-full

This may be obvious, but you aren't overfilling them, are you? If you fill a kettle past the max line, it could spout hot water.
posted by pracowity at 11:58 AM on December 7, 2023 [4 favorites]

I'm not sure what normal usage is for electric kettles, but your usage seems on the high side. Have you thought about getting a hot water dispenser instead? I would think that the heating mechanism for the hot water dispenser is more gentle overall and that it less wear on the machine.

I have never had the problem you describe with all the electric kettles I have had, but I'm only using them 1-2X per day.
posted by jraz at 12:12 PM on December 7, 2023 [5 favorites]

I blend and sell my own teas for a living. I've used the following heavily and had pretty good luck with Cuisinart and Epica 6-temp 1.7L stainless kettles.
posted by Text TK at 12:14 PM on December 7, 2023 [2 favorites]

Best answer: The one thing that will reliably kill kettles is extreme and repeated changes in temperature, so putting cold water into a just-boiled and emptied hot kettle or overfilling the kettle so it takes much longer to reach a boil.

For maximum lifespan fill the kettle to somewhere between 30% and 70% and when emptying leave at least a little hot water in contact with the element so that it cools down slowly.
posted by Lanark at 12:22 PM on December 7, 2023 [7 favorites]

Your problem is strange, I can't say I've ever experienced a kettle boiling over unless I overfilled it. I'm not nearly as diligent as you are about descaling and cleaning it, and I usually buy the cheapest kettle available. (Alas, I have not yet been able to find a kettle that works more than about ten years).
posted by mumimor at 12:22 PM on December 7, 2023 [3 favorites]

I mean, have you tried filling it only half full, according to the line on the kettle window?
posted by bluedaisy at 12:25 PM on December 7, 2023

We have normal consumer grade kettles at the office and they don't fail like that despite being boiled every 15 minutes or so every weekday (2 kettles for 80 people in a tea drinking culture). They last about two years with boiling at least twice as much, and tend to fail at the on switch. I vote either overfilling or some kind of slamming down that loosens the part that's supposed to turn the kettle off once boiled.
posted by I claim sanctuary at 12:25 PM on December 7, 2023 [2 favorites]

Are you at a high altitude where water boils at a lower temperature than the kettle designers might expect?
posted by fritley at 12:42 PM on December 7, 2023 [1 favorite]

Response by poster: @Lanark, you nailed it! I'm in the habit of running the tap for minute for "nice cool water" and pouring that into the kettle right after I've made my tea. For my next (and hopefully last) kettle, I will take care to let it cool to room temp before setting up my next cup.
posted by Jesse the K at 1:08 PM on December 7, 2023 [1 favorite]

I've never had this happen with any of my previous cheapo electric kettles from various brands, despite heavy use and never descaling (whoops). I would also have suggested overfilling as the culprit, but maybe Lanark does have the answer? TBH I feel pretty sure that I've refilled a hot kettle with cold water plenty of times as well, and I've never actually managed to kill one, just replaced them due to needing more capacity or a long-distance move.

Our household doesn't drink quite as much tea as you, but still a lot of tea (as well as pour-over coffee, which also requires hot water) and we switched to this Zojirushi water boiler. It keeps the water at a constant 208 degrees, ready to dispense, and can be heated to boiling very quickly. If you got the 5-liter version, you could refill once at the end of the day and never end up pouring cold water direcly onto the hot surface (if that's indeed the source of the problem).

I live in NYC and our water isn't the worst for limescale, but I only descale the water boiler a couple times a year. It's been going strong for 4 years of daily use without an issue and I expect many more years of no-drama hot water.
posted by sparkling at 1:29 PM on December 7, 2023 [4 favorites]

Huh, the cold-hot thing might be deforming things around the overboil safety, boiling for too long is a failure mode I've run across (though that one actually died for other reasons). Your use case seems to fit a samovar too - the classic mode is to use the teapot for "essence" / very strong tea and dilute it with hot water from the urn. They're likewise made for long term heavy use.
posted by I claim sanctuary at 1:44 PM on December 7, 2023 [2 favorites]

The only reason I can even imagine for this is that you're overfilling the kettle. That will make them 'boil over' every single time. I assume you are putting on/closing any lid to the kettle while boiling it - leaving the lid open/off can lead to them continuing to boil and never shut off for reasons I have no clue about.
posted by dg at 2:41 PM on December 7, 2023 [2 favorites]

I have two Chef's Choice model 675 stainless steel electric kettles. I usually only boil as much water as I need. I never leave water in them when not in use. Both have a small but non-objectionable amount of scale, but I have never descaled either of them in the 11+ years I've owned them. (In case you're wondering, I keep one at work and one at home.)

What's my secret to keeping the scaling down? Don't leave standing water. Otherwise the water evaporates and the minerals precipitate. At least, that's my understanding. There's a slight amount of water left after pouring it off, so a small amount of scaling.

My usual habit is to fill my (clean) mug with water and pour it into the kettle. Pretty much measures itself, and takes less time and energy to boil than if I fill it to capacity. And it never boils over. ... OK, it's done it once or twice when I overfilled it, but I know that I overfilled it, so it's no mystery and not the fault of the pot. If I had to guess, I'd guess you're overfilling it.

I cannot imagine any reason to boil more water than you need each time, nor any reason to leave standing water.

MHO. YMMV.
posted by jjnonken at 3:25 PM on December 7, 2023 [1 favorite]

If you drink that much tea, you should just get a Zojirushi Water Boiler and be done with it.
posted by rockindata at 3:47 PM on December 7, 2023 [6 favorites]

I stayed in a cabin a few years back way out in the woods on an island, the well water tasted amazing but scaled the hell out of everything. I noticed the electric kettle they provided there behaving really strangely every time i used it, even if it was filled up maybe 30-40% of the capacity line and everything.

What i'm saying is, i wonder if this is a water hardness/quality issue?

i also seriously second just getting a water boiler/dispenser. such a great, life changing object
posted by emptythought at 12:04 AM on December 8, 2023

Also: it is more energy efficient to boil just the water you need, rather than overfilling. The excess water will cool and need to be reheated otherwise. This adds up over time!
posted by Kiwi at 10:41 PM on December 9, 2023

I found it unclear when this problem presented itself -- does the overflow happen when boiling for tea or when refilling after making tea (when power would presumably be off)?

Other people have tackled other ideas, one part seemingly left unattended is:

I just need 212° water

OK, so you're not getting what you want from how your kettles behave at present, but it's multiple kettles from multiple brands each doing what is normal in your jurisdiction, so it's how you're trying to get to 100°c water -- any chance you're holding the 'On' button after the kettle is trying to cease heating water?

Boiling water is undergoing a state change to vapour and almost never shows 100°c on a thermometer because (i) evaporation happens anyway at lower temperatures and (ii) the average temperature of molecules hitting the thermometer is skewed to report the contact from more-sticky liquid rather than the gas and (iii) depending on your air pressure (or height above sea level) and ambient humidity, all the water may evaporate without any of it reaching 100°c.

I don't think you need 100°c water for good tea. Boiling hot-kettle water, yes, boiled once and not reheated, yes, (a reheat can confuse a kettle's automatic off by being at a different temperature to the water).

For good black tea, let the kettle boil, use just-boiled water to warm your teapot or mug and discard it before brewing with kettle water that you don't need to reheat. Black teas like hot-hot water, infusions and green teas lose a bunch of delicate flavour when you use boiling water and can deliver great tea from water no hotter than 65°c or (gets out list of firkins, chains, shillings, bailiwicks and quora, aha!) 150°F.
posted by k3ninho at 1:15 AM on December 11, 2023 [1 favorite]