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by firefax 70 days ago
it's never instant because boiling water takes sooooo longgggg. apparently uk teakettles are faster due to voltage differences? i want to look for a usb-c solution sometime
14 comments

The good news is that boiling water is not functionally necessary since the extraction was done up front. I drink it cold or with warm water. Boiling is hotter than I want to drink anyway.

If there's significant scale at the bottom it's possible it's making your kettle materially less efficient. If you put in like a cup of vinegar and a cup of water (you could probably dilute it more than that), heat it up and swish it around (it doesn't need to be boiling), it should all come off.

I found that 160F to 180F is enough for instant coffee, depending on personal taste and what you feel like at that moment. I have an electric kettle that has a several buttons for different temperatures, and heating only to 180F saves time over heating to boiling, plus I can drink it right away.
Yep, all the instant coffee jars I’ve seen have a note to use hot but NOT boiling water. And I’ve noticed that using too hot water can even spoil the taste a bit.

I usually turn off the kettle when the noise starts noticeably changing. This usually is something between 70-80℃.

Indeed. I have a Nespresso machine for when I need coffee quickly. As soon as I press the button, hot water flows in a trickle. It’s certainly not boiling but it’s an ideal temperature as a hot drink.
U. K. 240v vs. 120v in the U. S., twice the voltage == twice the amperage (EDIT: oops, wattage, for the same amps) == half the time to boiling. I will note that doubling the voltage will still not make it "instant". For that I think you need liquid oxygen[0].

[0] https://improbable.com/2018/10/26/a-look-back-at-george-gobl...

Twice the voltage == half the amperage for the same wattage. Are UK kettles higher wattage?
US circuits are about 15 amps; UK ones similar - but twice the volts.

So a US kettle is about 1500 watts, a UK one 3000.

You can get commercial water boilers in the US if you need.

or just use an insta-hot tap which is infinitely faster than an electric kettle. or a plain old kettle on an induction cooktop which will also be faster than a single purpose electric kettle.
Actually yes, around double the wattage. It's one of the things English people notice when they move to the US (true!).
3000 glorious watts
You can also simply keep water near boiling.
All the time? That's very inefficient, especially when running your boiler outside heating season and without a vacuum flask.

The actual solution is to boil small quantities of water. I can boil one cup in 90 seconds or so, even with the 120v handicap.

Or boil a larger quantity and fill it into a thermos. Perfectly fine for instant coffee throughout the day. (And without the coffee stains in the thermos.)
Sure, but efficiency wasn't the goal here. Anyway I use hot water enough (~6-10 times daily) that I don't mind spending extra for it
Most people boil too much water. Get a kettle that can take a smaller amount of water and then boil what you need. If that’s not good enough, you can get a kettle that keeps water warm and then you don’t need so much energy to boil it (or figure out a routine or trick to turn the kettle on earlier, eg a teasmade). If you want to throw money at the problem USB-C is not the answer (how does that even make sense??) but you could (a) get a 240V socket (eg NEMA 6-15) in your US kitchen and rewire a 15A 240V European kettle to the appropriate plug. Or get an impulse labs induction hob set. Their whole selling point is using batteries to be able to put more power into boiling water than they can get from the wall.
>If you want to throw money at the problem USB-C is not the answer (how does that even make sense??)

I thought maybe it could use a capacitor or something? I'm not an electrical engineer -- all I know is we have half the voltage here, and I've seen things like USB plates before -- the older type of USB... and USB C can power a laptop.

So I thought, since the English love their goddamn tea so much, they'd probably have a USB-C teakettle if such a thing is possible, and then I wouldn't need an adapter (if an adapter is even possible for higher voltage appliances like that).

Mine takes four minutes. Minutes are short in the morning in America :-(

The voltage isn’t really the limiting thing (you actually get 220 volts to almost any American home for some appliances like A/C or cookers). The issue is that the regular 110V circuits aren’t meant for more than 15A and that then limits the amount of power coming from your wall. If you change the voltage, you’re still bottlenecked by the power from your wall (and it is that power that is almost all turned into heat to boil the water).

A capacitor is too small but you could imagine a kettle with a battery to deliver more power than it can get out of the wall.

I shouldn’t have been snarky about your USB-C comment. I’m sorry.

I just made a cup of tea, here in the States[1], using science (which means I wrote it down).

I started with 300ml of water that I measured at 68.5F.

I dumped that into the Sunbeam Hot Shot[2] "hot water dispenser" that lives on my countertop (which is labeled as using 1450 Watts).

I pushed the go button and started a clock. It took 1 minute, 29 seconds to reach what I considered to be a rolling boil.

That's pretty good, I think. I could futz around with keeping a hot electric kettle going during the day and maybe save some time on everything after the first cup, but meh. This seems quick-enough, to me, and also avoids all chances of flash-boiling water in the microwave[3].

---

But that's not the interesting part. The interesting part is the math.

At my elevation, I added about 100kJ of heat to the water over those 89 seconds.

If the input power is 1450W (I didn't measure that; I just read it from the back), then ~23% of it was lost. Wherever it went (heating the appliance itself, evaporative cooling, whatever), that power was not included the final state of the water. That's hugely inefficient as a percentage.

But if electricity costs $0.19 per kWh, then I only spent about 7/10ths of 1 cent to boil this 300ml cup of water. (I could add or subtract 23% and it would still be an irrelevant part of my power bill.)

The cheap store-brand black tea cost me $0.0218 per bag.

So a cup of hot tea was a bit less than 3 cents. Not bad!

---

[1]: The freedom to use cursed units

[2]: The Sunbeam machine is no longer available, which sucks. They're simple electromechanical devices with no smarts at all and only a couple of moving parts, and I recommend one to anyone with 120v outlets who likes hot beverages one-cup-at-a-time.

[3]: I did that once. I reached into the microwave for a cup of hot water and it boiled explosively as soon as I moved it. It was very sudden and surprisingly painful. The first-degree burns healed up over the next couple of days. 0/10; worth taking extra steps to avoid.

I was thinking about this more.

A cup of tea is a bit less than 3 cents. The cost of water from the tap isn't enough to be worth calculating (and in a world of shortages, I live in a region where we have too much water). Heating is about 1/4 of the total cost, which is significant.

But that leaves me with a dirty cup that eventually needs to be washed.

So how much does it cost to clean the cup?

Starting with my kitchen faucet that had been doing nothing for hours, I started a clock and turned on the hot water and measured the volume that came out before it became warm-enough-to-wash-some-stuff. It took about 18 seconds and 1.6l to get to right about 110f, which my fingers determined to be "warm enough". The incoming water temperature is 58f right now. (The water heater is a recently-installed resistive unit.)

Raising the temperature of this 1.6l of water cost me almost exactly 1 cent, and that's all waste energy -- that's what it takes to get the process started.

Then I have to wash the cup. I didn't work through that, but I've done it enough that I can estimate that it takes me about 20 seconds total to scrub tea stains from a coffee cup and make it white again if I'm in a hurry about it. No big deal, time-wise.

But because I'm focused on washing the cup more than I am on conserving energy, I usually let the water run while I wash up the cup. That's another 20 seconds of running the hot tap (for 38 seconds total), adding another 1.13 cents (or 2.13 cents total).

---

So that's our minimum: 2.13 cents, just to heat the water to wash the cup with 38 seconds of running it. Maybe, some days.

But realistically, it's likely more than that. I've measured incoming water temperature to be as low as 38f here[1]. The water heater itself is set to 140f, and as a practical matter when I wash a single coffee cup I generally use 100% hot water.

In that worst case, it's more like 4.23 cents to wash a cup. (Again, if I'm hurrying. I don't always hurry.)

---

So the total cost of a single cup of tea, for me, is somewhere in the realm of between 5 and 7 cents. Heating the water is by far the biggest contribution to that cost.

And merely washing the cup by hand is a significant cost contribution at one end of the scale, and is the largest contribution at the other end.

That's surprising to me. These numbers still don't matter much (how many cups of tea do I drink in a month? or in a year? how often do I actually wash that cup?), but it's surprising enough that I think I'll start using the dishwasher for these things.

The dishwasher is a bit cheaper, and a lot lazier.

[1]: I'm not redoing worst-case for making the tea itself, because the water for tea-making comes from a large countertop water filter that connects to the kitchen faucet. The contents are generally always near room temperature, at the behest of the ambient environment that is controlled by a gas forced air furnace or aircon. I'm not getting that far into the weeds. :)

I'm in the UK but I have a kettle that lets you pick the temperature. I usually just use 50C (122F) for instant if I'm having it black, or 70C (158F) for a splash of milk. Boiling water would make an already miserable experience far more miserable.
USB-C PD has far lower wattage than the wall outlet anywhere in the world. Now I want someone to build a kettle that accepts a J1772 connection (for charging electric vehicles). That’s nowadays more common than any 240V NEMA outlets.
technologyconnections has connected several things to his car charger, including kettles
The UK is not an outlier here. Much of the world has the same voltage.
I just use the microwave TBH. 60s and done.
My completely unremarkable microwave is rated at 1800W whereas my unremarkable electric kettle is rated at 1200W.
Does it? It only takes like 2 min for my electric kettle to boil. If I was a more avid coffee/tea drinker, I’d get one of the always heated hot water dispensers that are common in Japanese households (def one of the appliances I miss since moving back to the US). Then you never have to wait.
In electric kettles or a microwave or even in a moka pot or another small container on a decent induction stove it's just 2-3 minutes. There was a video I can't find where they increased the voltage or something for a kettle and at one point it boiled the water in like 10-15 seconds.
Technology Connections?

https://youtu.be/INZybkX8tLI

It was another, shorter video, not by TC. Just different voltages (or maybe there were other variables) one after the other until the water boiled really quickly and afterwards the kettle blew a fuse or broke (can't remember).

I guess many people have tried doing something like this. But I'll watch TC's video, too - he hasn't disappointed me so far.

Edit: Watched it. Not the same video, but this one had a lot more info and troubleshooting than what the one I had in mind.

This guy (sunshine) designed a 3d-printed mocha pot that boils in half the time over a flame. https://www.youtube.com/watch?v=LuZiqLb70tM
If you’re brewing from ground you really don’t want boiling 212F water as you’ll burn the grounds. I do my pour over at 185F and get smooth ready to drink hot coffee with no/low acidity.
If you (for some reason) want low-acidity coffee, it’s better to just get a darker roast (if you can stand the taste defects).

Ideal brewing temperature depends on a lot of factors but even ultralight roasts don’t require anything near boiling.

For real instant: install a hot water tap. It has a small boiler under the sink that keeps the water at near boiling. I've got one and it's great - instant tea any time.
I considered this when I rebuilt my kitchen last year but the price was obscene - starting at $1600 AUD installed.

I bought one of these for $79 instead and I’ve been perfectly happy with it.

https://www.kmart.com.au/product/digital-hot-water-dispenser...

K-Mart? The dream of the 90s lives on in the land down under apparently...
Mine was about $1500NZD. That didn't seem like a big outlay when redoing the whole kitchen for nearly $60k.
Of all the things I have cooked on my induction cooktops over the years, boiling water fast is what I miss when I travel and have to use electric coils.