I'm not seeing the point here, especially for $120.

If it's fast, you'll end up with an extremely hot metal rod at the end of the cooking process, which you have to wash if you're heating anything other than water, and which will burn milk, soup, etc. Plus, you can't use it with metal containers, so a stainless-steel insulated travel mug is right out, unless you want to drink your tea with an oven mitt.

Plus, there's no mention of how much of a household's energy budget is spent heating water. I'm guessing "not very much," so energy savings are a red herring. $120 spent on LED lights or insulation around your hot water heater will probably save a lot more.

To make a single cup of hot water, it's much easier to: (1) microwave it; (2) stick in an immersion heater; or (3) pour a cup's worth into your kettle, turn it on, then pour the result back into your cup.

EDIT: Relevant, more detailed analysis: http://physics.ucsd.edu/do-the-math/2012/05/burning-desire-f...

Kettles are only for water. Ever.

Right but the article mentions how this invention will allow you to heat other liquids:

> The design’s capability of heating soup and food for babies as well as a coffee in a cup means the invention has left the kettle far behind, said Grase, 26.

Right -- perhaps I should have been more precise. For my 2-3 hot beverages a day, I just use a small pot with a lid and a rim shaped to pour well. It's cheap and works with all kinds of liquids.

In the UK 3kw kettles are common, so we can make tea in a reasonable time. Running costs can easily be 60GBP a year. Considerably higher if you are really into Tea

Well you can get a cup size immersion heater:

http://www.amazon.com/Instant-Immersion-Heater-Portable-Beve...

For about $9. We used to have those growing up.

But those can be very unsafe. (Or at least those designed and built by the Soviet industry were...).

I used to use these. Convenient on the go, always amazed my fellow travelers. But then I read an Amazon review where the guy used a multimeter to demonstrate that his model conducted electricity into his cup... and I decided to stick to normal kettles from then on!

If you pass an electric current through a metal coil you will create a magnetic field. A magnetic field will create an electric field. So it isn't surprising a heating coil produces an electricity into the cup. What is important is how much and where.

Most people, I assume, are smart enough not to put there finger into a cup of hotwater to find where the electric current runs through.

I had the additional problem of using a metal Klean Kantern to boil my water, so it was easy to forget to not touch the outside. (Mine never shocked me, but I get the feeling that these things aren't exactly made with care...)

Or (don't)build it youself! https://www.youtube.com/watch?v=aTejx32xVgc Could be the most UNsafe use of 'safe' razor blades.

Electric heating elements that can be used with a mug are nothing new. This is recycled 1970's tech, if not older. The only difference is that this is IH, which just makes it a more complicated mouse trap than the following compact (and cheap!) design:

http://ak.picdn.net/shutterstock/videos/1497616/preview/stoc...

That's something you can slip into your backpack for traveling.

Google image saerch for "immersion travel water heater":

https://www.google.com/search?q=immersion+travel+water+heate...

This IH-driven metal stick is not going revolutionize the way we heat liquids. If the market was eager for immersion heating, the existing immersion heaters would be everywhere. You don't see them much, though, and they have had decades to take off.

Brilliant, revolutionary, fresh, lets make a kickstarter and pour millions of dollars into this, after all its standing vertically!

http://termos.com.pl/p/2013/09/turystyczna-grzalka-do-gotowa...

In our office we have this

http://www.billi.com.au/

Spits out near-boiling water heated on-demand basically instantly.

Looks cool, but not sure it's something I'll ever be able to motivate a buy for.

(I went to the site and did a first scan with the words 'Spits out near-boiling water heated on-demand' and the first image i saw was this http://www.billi.com.au/cms_images/17_29-09-2012_2608.png which made me chuckle.)

Would be interesting to see some specs/measurements to substantiate their proposed energy savings -- without an insulated heating vessel it's hard to believe this is more energy efficient than existing technology.

Even using an insulated kettle, the water ends up in the same uninsulated cup.

It seems the biggest efficiency comes form heating much less water in the first place. Given that a typical cup of tea will stay hot for several times longer than the time spent heating it, the lack of insulation should be more than made up for by heating less water.

But, yes. Specs and measurements are required to substantiate specific claims.

A lot of teas need the water to be a specific temperature before they are put into cups/have the tea leaves inserted. Even if "the water ends up in the same uninsulated cup", the process of getting the water to the correct temperature will be more efficient in an insulated container.

Also, it's hard to believe that this would substantially decrease the amount of water heated. If you were super anal about only heating the water needed, then that's do-able with a tea kettle. If you're not, then even under the new model you would probably just use a kettle or pot most of the time.

Really?

We had those for at least 50 years:

http://www.img.chh.pl/large_size/cdeeb903fbbd7e9488757bb92fc...

I don't see how it's any different?

I'm not a tea drinker but I've always wondered why people don't just use the microwave.

So I don't have any real proof but there's a common belief that I also share that microwaved water tastes different from kettle-boiled water. I realize many people will dismiss this, but most of them probably aren't tea drinkers. And that all said, I'm sure there are a lot of people who use microwaved water for tea and are very happy with it.

Also, if you're making a pot of tea a kettle generally works better. Not sure if I'd want to put a whole teapot in my microwave.

Anyway, the real solution is to own one of these: http://www.zojirushi.com/app/category/water-boilers

Can confirm, just microwaved my tea water this morning. Still yum.

Personally, I don't use a microwave to heat pure water because of the danger of superheating (https://en.wikipedia.org/wiki/Superheating), which I have seen first-hand before.

Once you're keenly aware that this can happen, it ceases to be a danger. So it becomes pointless to avoid the microwave.

I enjoy superheating when making instant coffee; I like the burst of churn that happens when you sprinkle the stuff into the superheated water and try to nail it just right so that it fizzles vigorously but doesn't burst out of the cup, sending half the water over the counter.

You could... if you're a teabag-using plebe!

(Just kidding... but no, seriously. Loose leaf or bust.)

I always use the microwave, but some people think that makes the water taste funny. Maybe their microwave is so filthy that it does make the water taste funny.

You could. I find it is harder to heat the water to a given temperature and I also make a pot of loose leaf tea then keep it in a thermos. So need about a kettle worth of water. And imagine it is hard to beat direct resistive heating energy transfer. As opposed to say, run it through a transformer, mangetron, drive a cooling fan and spin the platter.

People are afraid the microwave will irradiate the water. Not really logical but it's hard to convince someone otherwise and since the alternative - putting a pot on the stove or turning on an electric kettle - is also pretty fast and convenient, there's not a lot of reason for them to switch.

Concern that a microwave oven will irradiate the water is usually logical; it is just that the logic makes reference to ignorant beliefs, rather than facts. :)

You need to boil the water for optimal black tea flavor, which results in heating the mug/glass to the point it's too hot to hold, and causes a portion of the water to splash out of the mug in the microwave once it bubbles over.

Well, I use.

But I'd prefer a Kettle. It seems to go faster and you have better control of the temperature (since you see what's going on and can shut it down easily, I don't like coffee with boiling water)

Big-ass induction coil... bet it would do a quick number on a credit card. Or a thumb-drive... or a phone... "Oh, is that one of those induction battery chargers?" fzzzzt!

$120 is expensive.It would take 16 years to make 2 cents on your investment. You don't believe me, here is my calculation:

Regarding energy usage: 1 cup of water is 28 grams t0=25s t1=100s C=4.1810^3J/kg.s Q=mc(t1-t0) for boiling Q=.0284.1810^375=8778J 8778J correspond to 0.00243833333 kilowatt hours so if you pay .11$ per Kw hour we are talking about 2 cents per cup! If we are wasteful and 2 cups of water and drink 1 we have wasted 2 cents. How much time I have wait to make profit on my 120 investment. 120/0.02=6000 And if you drink 1 cup of tea a day. You have wait 6000/365=16 years. You have to wait 16 years to make money on your investment.

Uh, no, a typical cup is way more than 28 grams of water.

A standard metric cup is 250 ml, so you're off almost by a factor of 10 on that value, at least. I didn't check your calculations, perhaps that was just a typo though.

I wonder if there's any technical reason they wouldn't be able to have a thermometer at or near the end of the rod. It would be interesting to see it heat the rod rapidly and then fluctuate the induction base when an ideal temperature is reached in order to maintain that temperature. Ideally wirelessly, but I suppose the top of the rod could have a tether back to the base.

Different substances have different temperature restrictions, but it seems like for rapid heating, you could target 100C at the end of the rod but reduce power as the liquid (perhaps monitored by a second thermometer higher up the rod) approaches 70C, or whatever your preferred temperature is.

I think it'd be pretty difficult to do for arbitrary liquids, because i imagine there would be some non-trivial temperature gradients. You'd probably have to account for the heat capacity and thermal conductivity of your soup to get it close to right. Simpler and cheaper to just use an old-fashioned thermocouple that clips onto the mug wall or something.

That's a good point. Perhaps an infrared sensor pointed down from the handle would give you meaningful data.

because it would be extremely hot if it's inside the rod, giving the wrong temperature

so it would be useless because all of the hot liquid is around the rod, while the coldest liquid is the farthest from the rod

Would it be the wrong temperature if what you want to know _is_ the rod temperature?

I would agree the liquid surrounding the rod vertically would also be above the average liquid temperature. It seems like you could use a different material and shape farther up to get a more accurate liquid temperature.

OT: I've always wondered, why aren't pots (edit: all pots, not just water kettles) insulated? And to take it step further, why aren't the stove burner and its interface with the pot also insulated?

To test the energy loss yourself: Put a pot on the stove, turn on the stove, and hold your hand over the pot, next to the pot, and also touching the side of the pot. (DO NOT DO THIS. It's dangerous. Do it as a thought experiment instead.)

The nice ones are (and solve this wasted energy problem, and eliminate time spent waiting for water to boil, and any rain dance to get non-100C water)

https://zojirushi.com/app/category/water-boilers

Thank you. For people who want to know more about Zojirushi's tech:

http://www.zojirushi.com/product/product_wb_01.html

Do you know of insulated products for other types of pots, besides kettles?

probably cost. I imagine that there's some insulated things somewhere out there

It should come with a set of tea spoons with insulated handles, then you could put instant coffee in your cup, stir and heat with the same object!

It should also come in a 'kettle' so that it can be used conventionally in a receptacle with pouring spout. This would make migration easier. A kettle with a removable element that you can put straight in your cup.

This is a great place to ask 2 questions:

1) Anybody using single serve electric kettles that have variable temp heating? Some teas need lower temps and I'm usually drinking 1-2 cups at a time.

2) I've always imagined building some kind of adjustable mechanical whistle into a kettle to accomplish this. Is that possible to make a kettle whistle with "low" steam?

Chinese tea shops often use little electric kettles (maybe two cups worth) that sit on a base, and are kept at a constant (adjustable) temperature, usually just below boiling. The constant heating is good for lengthy tea sessions -- if you just want a cup or two you could probably just switch it off when it reaches the right temperature.

I've "solved" the problem for myself by buying a pen-sized Thermaltake food thermometer. You heat your water until it's slightly above the right temp and then let it cool a bit while measuring.

I like having a more scientific approach to my tea-drinking. :)

~ 1 in 1000 children in the UK suffer from scalding accidents every year involving kettles, so anything to reduce the quantity of boiling water around is good, I've got one of these, works just fine http://www.onecupkettle.co.uk/

I have a small and cheap kettle (1L), which I just fill with the amount of water that the cup has. Problem solved.

My grandparents use this little boiling device. May not be fancy looking but it's does the job, it's cheap and portable. http://imgur.com/gallery/Yk23aAl/new

How fast is it? It would have to compete with the speed of an electric kettle or microwave.

Also, other than the fact that it uses induction, there are many single cup liquid boilers on the market. Their design seems really clean and efficient, though.

So it works with glass, ceramics, anything non-ferrous.

What if I had a ferrous mug with say a wooden handle, would I still need the iron rod, or would the system not work at all?

Your cup would be insanely hot near the rim, so don't drink from it!

Why not just measure the water in your cup first, then pour it into the kettle? Seems to solve the problem for me...

That's in the article: most kettles have a minimum-fill line, which is often way above the volume required for a single cup.

Brilliant is an understatement for this innovative design! But it takes probably much longer time for the water to boil.