Engineers introduce 'beans' to cool and then maintain hot beverage temps

May 03, 2011 by Bob Yirka report

(PhysOrg.com) -- Buddies and mechanical engineers, Dave Petrillo and Dave Jackson, have, thanks to Kickstart.com, begun a business selling the Coffee Joulie (clearly a play on the word for joule, a unit of energy, and jewel, the stuff you wear as bling), a stainless steel bean they’ve invented that will first cool a hot drink, then maintain it at a consistent 140°F (60° Celsius) temperature for up to five hours if the container is kept closed.

Generally used with more than one “bean” at a time, Joulies have a special secret ingredient inside of them that works first as a heat sink; absorbing heat from the hot coffee or other beverage that surrounds them, until reaching 140F°, at which point the secret ingredient melts causing it to reverse course and to then start working as a heat source as the absorbed heat is radiated back into the beverage as the secret ingredient slowly solidifies once again.

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The Dave’s as they’re called, won’t let on what exactly is inside the , but they claim its safe enough to ingest. They refer to it as a “non-toxic phase change material.” The outer cover is all stainless steel, which they say is the same grade as that used for cutlery, which they point out, has a very long safety record as a means for both the drinking of hot beverages and for stirring them.

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Coffee Joulies cool your coffee to a drinkable temperature in under 90 seconds.

A natural question might be to ask if the beans might work for cold beverages as well, as a replacement for ice cubes, but that question has not been addressed thus far. At this point it would seem unlikely as there is no indication that the special ingredient inside the beans would absorb and hold any more of a chill than freezing anything else and dumping it in your cup.

At any rate, to use Coffee Joulies, once on the market that is, coffee drinkers would place a few of them in a cup, pour in their hot beverage of choice, wait a moment for the beans to cool, then commence to drinking. Afterwards, the beans could be washed the same way as other utensils, though they likely would only need a little rinsing. No word yet on whether the phase-change material inside the beans degrade over time, and if so, how long it might take.

Explore further: LG Chem's super-efficient OLED lighting has life of 40,000 hours

More information: www.joulies.com/

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User comments : 22

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kaypee
not rated yet May 03, 2011
Sounds like the bean might be filled with sodium acetate. The melting point of sodium acetate trihydrate is about 58C (136F).
Javinator
not rated yet May 03, 2011
A natural question might be to ask if the beans might work for cold beverages as well, as a replacement for ice cubes, but that question has not been addressed thus far.


No, they would not (at least these specific beans anyways).

The phase change material holds the temperature where it is because the temperature of the phase change material at the time of the phase change is a constant.

In this case, the stuff in the Joulie would first begin melting (as the temperature of the coffee is above its melting/freezing temp of ~60oC) and would steal heat from the coffee to do this (endothermic process).

Once the temperature got down to the melting/freezing temperature, the now melted liquid in the Joulie would begin to solidify (an exothermic process) holding the temp constant until all of the phase change material was frozen. The temperature would then continue to decline as normal.
jscroft
3 / 5 (2) May 03, 2011
If the coffee cools to 140 deg in a third the time and stays between 130 and 140 deg twice as long, one wonders whether it drops below 130 deg BEFORE or AFTER the control cup does?

My guess is that they both hit 130 deg at about the same time. The Joulie won't keep your coffee hot longer in ABSOLUTE time... it will just cool the coffee down to a drinkable temp and KEEP it there.
Javinator
not rated yet May 03, 2011
If you had a phase change material with a melting/freezing temp near ~4oC (heavy water for example...although I wouldn't recommend that) or so you could use them in the same fashion to hold the temperature there.
jscroft
3.7 / 5 (3) May 03, 2011
Of course, you also have to factor in the fact that the liquid volume is reducing as you drink the coffee, and that this reduction starts SOONER than for the control... but probably AFTER the Joulie has undergone its phase change. So, basically, the Joulie is maintaining the temperature of the coffee you HAVEN'T drunk with heat scavenged from the coffee you ALREADY drank.

In this "dynamic" model, I guess I'd have to expect the coffee REMNANT to remain hot LONGER than the control in absolute time, if it is consumed at the same rate with respect to temperature.

That's brilliant!
Eikka
not rated yet May 03, 2011
Sounds like the bean might be filled with sodium acetate. The melting point of sodium acetate trihydrate is about 58C (136F).


That's what I was thinking.

But sodium acetate tends to supercool easily, in which case it will melt and then not release the heat back by re-crystallizing below the melting point. That's how heat pads work - they have supercooled sodium acetate inside, and the crystallization is started by clicking a small steel disc.

They have to add some sort of permanent seed crystal in the bean to start the process every time. Perhaps that's the secret ingredient.

bg1
not rated yet May 03, 2011
The heat needs to be taken up by the "bean" faster than its taken up by the surroundings. The heat loss to the surroundings will occur at 140° rather than at a higher temperature, and so will be lower.
pauljpease
not rated yet May 03, 2011
@jscroft,

excellent comments! I would also add that a major source of cooling for hot coffee is evaporation (highly endothermic process). So, all other things being equal, adding these things would cool the coffee off, decreasing the amount of evaporation, therefore holding heat for longer. Of course a thermos with a lid works well too.
macsglen
5 / 5 (3) May 03, 2011
So, you get about two-thirds of a cup of coffee instead of a whole cup -- and then risk swallowing one of these things, or having it slide back and whack you in the teeth.

What they should do (Version 2.0) is to incorporate the material into a fixed capsule in the bottom and/or walls of the cup.

And, if they want a market for this, they'd better be able to produce it cheaper than an insulated mug.

Personally, I drink my coffee to quickly for it to get cold in the first place.
sender
not rated yet May 03, 2011
Amateur chemist,
The data relation of phase transition temperatures for the 'hidden' core seems to correlate well with:

https://secure.wi...7s_metal

Glad to deconstruct this mystery :}
panorama
not rated yet May 03, 2011
and then risk swallowing one of these things, or having it slide back and whack you in the teeth.


Seriously. Last thing I want in the morning is a chipped tooth...or asphyxiation.
Personally, I drink my coffee to quickly for it to get cold in the first place.

I agree, while this new tech is interesting I'd rather not have the hazard of a metal bean in my coffee.
PinkElephant
not rated yet May 03, 2011
@macsglen,
And, if they want a market for this, they'd better be able to produce it cheaper than an insulated mug.
To be fair though, an insulated mug doesn't rapidly cool your coffee to a drinkable temperature, then hold it at that temperature.

My biggest problem with insulated mugs and thermoses is the unfortunate side-effect of scalding my tongue/mouth/throat by trying to drink the hot drink before it had sufficiently cooled down.
hooloovoo
not rated yet May 03, 2011
Well, I drink coffee far too quickly for it to get cold, and if it starts off too hot what's wrong with a little cold water?

Cleverish mechanism I suppose, which may be useful in other areas, but as far as coffee goes it seems like a useless gimmick.
jwalkeriii
not rated yet May 03, 2011
Just don't swallow one.
Isaacsname
not rated yet May 03, 2011
If I was accustomed to drinking tepid fluids all day I'd love it. Usually a good cup of joe is gone in under 10 minutes.
Clouds_Phantom
not rated yet May 03, 2011
Thinking about the reactions in the liquid wouldn't this be best to use in a thermos?

It would cool the drink / soup down to a level that you could consume it easily and then would help hold the temp to a reasonable level for longer, assuming that you were consuming it at a regular pace based on it being at a comfortable temp.

Another way to put it would be, for a lunch break drop one into your hot soup in a thermos and eat without scalding early in your lunch period.
macsglen
not rated yet May 04, 2011
@macsglen,
And, if they want a market for this, they'd better be able to produce it cheaper than an insulated mug.
To be fair though, an insulated mug doesn't rapidly cool your coffee to a drinkable temperature, then hold it at that temperature.

My biggest problem with insulated mugs and thermoses is the unfortunate side-effect of scalding my tongue/mouth/throat by trying to drink the hot drink before it had sufficiently cooled down.
Excellent point, Pink. I should have said, if they want a market for these, they'll have to do some outstanding salesmanship -- and I still think they should integrate it into the cup.
jscroft
1 / 5 (1) May 05, 2011
Thinking about the reactions in the liquid wouldn't this be best to use in a thermos?


I would say not... at least not in the sense of replacing the vacuum layer with this Joulie material. The reason is simply that, if you did, MOST of the heat absorbed by the Joulie layer would be released into the ROOM, not the beverage, because the room is colder than the beverage.

Location matters. When the Joulie is IN the beverage, it's a thermodynamic buffer. When it's BETWEEN the beverage and the rest of the universe, it's just a conductor.
Isaacsname
2 / 5 (1) May 07, 2011
The real problem here is that delicate aromatics that give a good cup of coffee it's character are spoiled rather quickly once brewed, so this invention might keep coffee warm, but it won't keep coffee good. True aficionados know this. It might be suitable for Maxwell House, but for higher shelf java, noe, not so much.

'pats self on shoulder and nods in agreement'
jscroft
1 / 5 (1) May 10, 2011
@Newton: If you've got that much time to devote to appreciating fine coffee, odds are your unemployment check won't cover a set of Joulies anyway.
Javinator
not rated yet May 10, 2011
he real problem here is that delicate aromatics that give a good cup of coffee it's character are spoiled rather quickly once brewed, so this invention might keep coffee warm, but it won't keep coffee good.


You should pay attention to what the Joulies actually do. Not only do they hold the temperature steady at a good, warm drinking temperature, but it brings the temperature down faster so it can be consumed sooner after brewing.

If anything, these devices allow the beverage to be consumed sooner, leaving more of your "delicate aromatics" unspoiled when the drink is ingested.
jscroft
1 / 5 (1) May 11, 2011
Hmm probably also worth pointing out that aromatics are generally more volatile as temp increases, so lowering the temperature faster will keep more of them in solution.