Musings on cooling down coffee...

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related coffee question,

when I have coffee I put 1 teaspoon of coffee in a mug, add a splash of milk and sugar then stir. then add boiling water.

is that a latte? is that what I order in starbucks to get the same thing?
 
Man of Honour
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It makes far more sense to add milk when it's too hot to drink than to wait for it to cool then add milk, cooling it further.

To be more sciencey though, the coffee is cooling at the quickest rate at its hottest temperature i.e. the moment its poured. By decreasing the temperature differential between the room temp and the coffee temp as soon as possible the rate of heat loss is slowed. Put the milk in straight away.
 
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It makes far more sense to add milk when it's too hot to drink than to wait for it to cool then add milk, cooling it further.

To be more sciencey though, the coffee is cooling at the quickest rate at its hottest temperature i.e. the moment its poured. By decreasing the temperature differential between the room temp and the coffee temp as soon as possible the rate of heat loss is slowed. Put the milk in straight away.

Ah, but the OP has made the point that if the milk does not cool it sufficiently, then the resulting lower heat differential will slow the heat transfer after the milk addition. This requires more science.
 
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Step 1 - Make the coffee.
Step 2 - Add the milk.
Step 3 - Muse for 5 minutes over possible ways to cool the coffee down.
Step 4 - Give up because its clearly impossible.
Step 5 - Drink coffee.
Step 6 - Be impressed by the witchcraft that has somehow occurred.
Step 7 - At some point you wet yourself.
 
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Get a set of Coffee Joulies, they cool down the coffee and then keep them at that temp for longer. I personally think they are a ridiculous idea but someone buys them (someone on here has a set from the original lot on Kickstarter).

Those look simultaneously awesome and utterly pointless :D

That was me. I bought them from Kickstarter. I just thought they were a funky idea, but they really work.

I don't use them everyday, but if I'm going out somewhere where there is no decent coffee then I'll take a small 1litre thermos out with me with all 5 of them in then just filled with coffee.

The thermos is a chap thing that isn't particularly good, but with the joulies it kept the coffee hot for 9 hours last time.
 
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Add in boiling water, a little cold water and milk to desired drinking temperature.

Boiling water & coffee? Boiling water & coffee? Boiling water & coffee?

Get out. Get out now! :mad:

It makes far more sense to add milk when it's too hot to drink than to wait for it to cool then add milk, cooling it further.

To be more sciencey though, the coffee is cooling at the quickest rate at its hottest temperature i.e. the moment its poured. By decreasing the temperature differential between the room temp and the coffee temp as soon as possible the rate of heat loss is slowed. Put the milk in straight away.

But I wanted to know the fastest and most efficient way to cool it. So with your more sciencey bit, it would actually be better to wait until it's cooler before putting the milk in, as it will lose heat to the environment quicker that way.

Did that test in GCSE Physics. Leave the milk out till you want to drink.

Do you have graphs etc. to prove this?! :p

Well, since this is less musings about coffee, and more musings about thermodynamics and heat transfer, I applaud the OP. I'm sure, from the OP, that this is already common knowledge, but it may help if not

Q = mc*Delta T

Q = heat energy ; m = mass, c = specific heat, delta T = the change in temperature

So you'll need to know the mass of the mug, assume a mass of 1 kilo per litre for the coffee (if it's instant anyway, it's mostly water) and maybe marginally higher for the milk, but we could fudge it a bit.

If you measured the temp before and after adding the milk, we can work out the energy exchanged at different temperatures, and you could compare that with set time periods of heat radiation with and without milk.

Do it. Graph it. Let us know the results.

I will try. Although explaining to my girlfriend why I'm up at 5am making 10 cups of coffee might be interesting...
 
Soldato
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I will try. Although explaining to my girlfriend why I'm up at 5am making 10 cups of coffee might be interesting...

Tell her you're really tired and have a long day ahead of you :p

Seriously though, you could simply try it with hot and cold (fridge temp) water to get a rough idea. Use a measuring jug (preferably two to make sure the jug temp doesn't influence it) and thermometer and away you go.
 
Soldato
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Yeah you dont want the taste of that instant coffee to get ruined now do you?

Shush you! :p

Tell her you're really tired and have a long day ahead of you :p

Seriously though, you could simply try it with hot and cold (fridge temp) water to get a rough idea. Use a measuring jug (preferably two to make sure the jug temp doesn't influence it) and thermometer and away you go.

Pretty sure the impurities in the coffee would affect the results.
 
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Shush you! :p



Pretty sure the impurities in the coffee would affect the results.

In a perfect world, we would take that into account. In a GD thread on "musings about coffee", we will assume the gram of instant granules dissolved in the water will have a small effect on the overall heat transfer. I do think that the milk would have a significant effect, however, depending on whether it's skimmed or not.
 
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