Science Question: If I Leave My Spoon in My Hot Coffee (or Beverage), Is It Pulling Heat or Helping to Retain Heat?

[AmandaYVR]

Help me, science nerds. I suck at science. I've been wondering this for a long time. Inquiring minds need to know.

I don't want to keep a spoon in my coffee while I'm drinking it, but I'm interested in when I'm making it up (and using a hand frother to make up some foam for a pseudo cappuccino), if in that interim, after stirring in the sugar, should I keep the spoon in or take the spoon out? Which will keep the coffee hotter longer?

I think the layer of milk foam does help to retain the heat a bit, making a somewhat protective 'cloud pocket' I'm calling it. But would a spoon sitting in it while I'm doing this pull heat or retain heat?

Would you change your answer depending on the mug material? Ex: ceramic, bone china, glass, metal, plastic, paper cup. Obviously metal is far more conductive than paper and plastic, and ceramic and bone china are... what... in the middle of efficiency? I always use ceramic mugs at home.

I've tried various things to keep my one cup of coffee as hot as possible for as long as possible. I have a hotplate. It tends to burn the coffee, even on low temperatures. 176F seems to be the best temp to drink the coffee, but it burns. Lower temperatures will burn the coffee when the quantity is lower in the mug (about halfway empty; or halfway full, lol).

I also have a ceramic top/lid. I'm back to using that a lot now. I find it works the best. But, of course, you have to keep taking it on and off for every sip.

I don't use coffee makers, so there is no pot to pull from. It's too much volume of coffee. I"m sensitive to caffeine.

Anyway, any science-y thoughts or advice, I'm interested. Use all the jargon. Talk over my head,, lol. The more science, the better...

Don't use the spoon. Leaving the spoon in the ceramic mug with a hot beverage will cool your coffee because it's pulling/absorbing/extracting the heat.

Use the spoon. Leaving the spoon in the coffee will help your coffee stay hot because it's helping to conduct the heat into the coffee.

Depends on the mug material.

I have no friggin' idea. Here for the results!

Updates

6 mo

Thanks, everyone. You were all right, and @bowenw dug up an engineering forum with study on stackexchange, so the answer is definitive. No spoon for the win.

🙏🏻

[Friendlybro79]

The best temp to drink coffee and actually taste it is around 120-140 degrees. 176 is not the best temp and you prove it by saying but it burns.

I find 120 too cool but 140 is hot (not scalding) without burning and you can taste the flavor of the coffee. Over 160 and your taste buds really can’t register anything good, especially if you’re drinking specialty coffee. It will taste burnt and bitter.

That said, I don’t think the spoon is the problem as it is your cup. Get a small tumbler with a lid to maintain the temp longer without additional heat like your hot plate which will ruin the taste of the coffee typically.

How long does it take to drink your coffee out of curiosity?

[Friendlybro79]

Oh and if you want to lessen cooling of the coffee when putting it in a tumbler rinse the tumbler out with hot water first. Let it sit in there while you make your coffee. It doesn’t have to be filled with hot water but enough in there to warm the tumbler. Don’t be like me and forget to pour the water out before putting the coffee in lol. I love making pour overs and grinding before every cup if you ever want to pick my brain

[AmandaYVR]

A long time. Hours. Though I of course don't have the expectation that it *should* stay hot for as long as I want.
I'm not sure what my expectation is. I guess I don't have one. Because science is science. Can't wish it to be something else. Was just wondering the best method for best result, eeking out every degree, lol.
And I"m into a green tea caffeinated, mildly carbonated beverage these days (WakeWater, which is only sold in Canada right now), so, partly because I'm not enjoying the latter half of the cup of coffee, I move over to a can of WakeWater for the next few hours.

I made a mental note about your coffee passion. I was in the market for a compact espresso/cappuccino maker at one point, and did get overwhelmed about that world. Cancelled the idea and am still on a basic, individual drip cone system still. With side frother. Mostly because of counterspace limitations, but also noise in the morning. One day maybe we'll get one and I'll hit you up for some tips. The coffee world is much like the wine world, isn't it, some similar parallels. Though with wine, I already know what I like (pinot noirs, and the occasional merlot or Montepulciano D'Abruzzo, etc.) I have about six bags of types of coffee currently, but I don't buy beans and grind often, so I'll leave the 'Coffeephile' room now...

[Friendlybro79]

I totally hear you on all of this lol. The science is science made me laugh but a good tumbler should keep it hot for hours. It is very much like wine as well. I'd say I'm not an expert but I am an educated consumer with a bunch of different coffee gadgets. I started liking wine first, then coffee (specialty coffee), and now bourbon. The last one though took me some time because I don't really like to drink excessively.

Good luck on the journey. Be careful because you can easily go down the rabbit hole lol.

[AmandaYVR]

Omg I am ALL about rabbit holes lolol. (To the point I was even going to use it for a book title. So me.)

I don't like dark liquors at all, but just for fun at a wine festival one time, I signed me and my husband up for a whisky tasting class. We learned a bunch about the various notes. Or maybe it was a food festival. Anyway, I like the idea of deconstructing flavours. I've seen tequila flight [school? lol] on reality dating show dates, though I don't drink tequila.

I'm kind of particular about what vessel I drink out of. I will only use ceramic.
My husband went a bit nuts on that whole Stanley thermos-collecting thing. (He pretended he had a sudden need for hydration, of course, but it was FOMOCA, Fear of Missing Out Collection Anxiety, I'm sure - I just made that up, by the way.) A bit like that Starbucks Bear Cup nonsense, though the bear is much less useful than one that controls temperature.
Anyway, yeah, though he bought me a nice looking tumbler (black with pearl-coloured Japanese cherry tree flowers), still, it's plastic, and I can't get excited about sipping from plastic.
(He also bought me a crystal liquor carafe, so he does know me well. I am a glass fanatic/enthusiast. Just love the material. (Except mugs.) On this, I will buy things just for their intrinsic beauty, not utility.)
A tisket, a tasket, tangents are so easy...

[AmandaYVR]

Have you ever drank from a squoval mug? (This, I am not making up, lol.) Square oval.
I had a favourite mug for years, like this. It was tall, dark green, squoval, with a great print, too. It was perfection.
It cracked, had to throw it out, sadly.
I bought my husband one a bit similar one day, but he thinks that shape is awkward to drink out of. Strange, to me. I find it lines up perfectly.

In design, females tend to prefer round shapes. Males prefer angles.
I'm an outlier.

[bowenw]

Someone tested this. The spoon in the cup will draw heat out. Here are the test results:

https://physics.stackexchange.com/questions/5265/cooling-a-cup-of-coffee-with-help-of-a-spoon

[AmandaYVR]

This was excellent, thanks so much for finding and posting.
Interesting that it's about cooling your coffee, not keeping it hot. Other than the woman whose legs got scalded by a McDonald's hot coffee whose lid was not put on tight (and won the lawsuit), I didn't know cooling a beverage was ever an issue.
Anyway, that study proves it unequivocally now - no spoon for the win. The quandary will now thankfully not be part of my groggy morning routine. It's done and dusted.

[bowenw]

As you probably know, a good trick is to warm the ceramic mug beforehand. An inexpensive electric mug warmer is my favourite table gadget.

[AmandaYVR]

I hadn't thought of pre-warming the mug, but based on your and other suggestions here, maybe this is the ticket. I have a hotplate, as I mentioned, but I notice a difference very quickly (and at too low a temp, the coffee cools). Are you saying you warm your mug, empty, on the hotplate first?
That's an interesting idea. Though I don't really have room to keep it out on the kitchen counter all the time and the receptacles are full and/or very stiff and I hate plugging things in and out.
Would it be bad to microwave the mug, empty, while the kettle is warming?
At the very least, I can add some hot water from the tap, in the meantime I guess.

[bowenw]

I prewarm the mug with hot tap water or boiling water beforehand. If you're boiling water in the kettle anyway, you could pour some into the mug, let it sit for 15 seconds, then dump the water. You could probably do it in the microwave, but you may want to have water in it.
I don't use my mug warmer until after the coffee is in it.

[AmandaYVR]

Ok, so I'll pour some of the kettle water into the mug beforehand, before boiling point but on its way to the boil.
Thanks, that's the new plan.

[bowenw]

The water can be boiling.

[AmandaYVR]

But at the point the kettle is boiling, that's when I'm pouring it through the cone filter into the mug.
There would be no point swishing boiling water into the mug, only to immediately throw it out and drop in the coffee, right? This heat-the-mug method is just to get it warmed up beforehand if possible. And not-quite-boiling water from the kettle will be much hotter than tap water from the faucet.

[bowenw]

What you are proposing sounds perfect. Hopefully you will report back your findings.

[bowenw]

Thank you for the MHO. 😊 ☕

[Friendlybro79]

This is great. Nice find

[WindAtMyBack]

If the spoon is hotter than the coffee (which is unlikely), it will add heat to the coffee for a short time, until the coffee and spoon are the same temperature. Once they are the same temperature, the spoon will draw heat from the coffee and radiate that heat through the handle into the air. It will basically act like a radiator - hence the name, it radiates heat, much like the radiator of a car.

If the spoon starts at a lower or same temperature as the coffee it will draw heat from the coffee right from the start.

One last possibility is if the surrounding air temperature is higher than the coffee. In which case the spoon will add heat to the coffee until both the coffee and spoon reach the ambient air temperature.

[Lynx122]

Metal can only pull heat from something, that's why it always feels cold when you touch metal because it conducts energy. So as soon as it's in contact with something that has more energy it will absorb it at the end that's in the coffee and disperse it to the air at the end that's out of the coffee. That's why you don't want to touch metal when it's really cold because it will take all the energy from your body and your skin could stick to it but that's a separate issue. This is why for example you make a pan out of metal because you can heat the metal and it will heat the water. But you don't want to make a house out of metal because it would be very hot in the summer and very cold in the winter.

[exitseven]

Heat flows from a hot place to a cold place. If the spoon is colder than the beverage it will absorb some of the heat of the beverage and make it cooler. Then the handle of the spoon is exposed to the ambient temperature in the room and will dissipate some of the heat to the surrounding air.

Happy New Year , Amanda

[AmandaYVR]

Happy new year, exit.

[NathanDavis]

heat loves to travel... metal loves to transport... temperatures love to trade

so... that spoon will pull the heat, spread it all over its surface, and then it will release and exchange it to the much cooler air all around it, lol

[NathanDavis]

and the truth is, a coffee will never last hot long enough for a multitasker or a high-focus person... lmao

[ArrowheadSW]

Being a science nerd and a coffee drinker, I've never thought of this! LOL... Leaving the spoon in the coffee would slightly hasten the cooling of the coffee over time. The heat from the coffee would travel up to the handle of the spoon and the heat would dissipate into the surrounding air.

[Agape93]

It's pulling heat from the drink, and expelling it through the part not in the drink itself.

[Mike_Hum]

If you put a spoon in a beverage hotter than the spoon, the heat will move from the beverage to the spoon. Metal is a conductor of heat.

[Daytoday79]

Pulling heat at first until spoon and coffee are the same temperature

[I_am_a_human]

Cooling it.

With that spoon in the coffee, you have increased the surface area in which the heat is radiated (extra area is from handle sticking out).