[Womble]

Fsmnutter is right.  The driving force for losing the the heat is the temperature difference between the coffee and the air. If you put the milk in first, that reduces the driving force for heat loss, so less heat gets lost whilst you're waiting your 10 minutes.

Rosemary - in case you were wondering, Q=UAdT(Lmtd)   

[Alistair]

Surely it depends on what your drinking it out of, I.e. Tall mug, cup etc cos of its surface area in contact with the air?

I only drink out of a saucer these days

[jaykay]

Yep, rate of cooling is dependent on the difference between the drink and the room temp. So BH's will cool faster in the first instance. However, it will have been hotter to start with, and they'll both cool to room temperature in due course.

The point is where each one is on its cooling curve, after 10 mins. Which will depend on starting temp, the room temp, how much milk you put in, what temp the milk was......

I see an experiment and thermometers in your future 

[doganjo]

If I'm going outside I put my hot drinks in one of these Thermos mug thingies - does that make a difference? 

[Womble]

If I'm going outside I put my hot drinks in one of these Thermos mug thingies - does that make a difference? 

Yes.

[SallyintNorth]

You are not disappointing me, TASers !    

You may be right about the experimenting, jaykay - but not till all me pet lambs are weaned!  lol

[mab]

I'm with fsmnutter too; leavng it without milk will result in more heat being lost.


mine is a totally unbiased opinion as I don't drink tea or coffee.

[ladyK]

Fascinating. Never thought of all that 

[Mammyshaz]

I disagree with fsm nutter  and mab.

The liquid only seems to cool quicker. It's hotter to start with as it hasn't had the coolant of the milk added.
If the milk is added immediately then the temperature drops suddenly and subsequent cooling is done at a steady rate. The drink without milk rapidly loses it's first bit of heat then slows down.

Then if my drink and OH drink is made at the same time, both with milk added at time of making then mine will be cooler.
oH cup is tall and thick walled, mine is smaller with a wider open top thus the heat will evaporate quicker.

Then if OH takes his outside while chopping wood,  his will cool quicker than mine being cupped in both hands in front of the log burner 

[HesterF]

Agree with Fsmnutter and Womble. It's not a linear function. The greater the differential between the liquid temperature and the air temperature, the greater the energy loss, therefore the faster the temperature fall. When you add the milk, the liquid will average the temperature between the coffee and the liquid (weighted average because there will be more coffee than milk). I've started jotting down numbers but then realised that's all getting a bit obsessive. But basically you're better off leaving it hot for longer so that the most evaporation happens, leaving the coffee cooler and then averaging by volume between the cooler coffee and milk rather than reducing the temperature first with milk when the evaporation will then be less so it won't cool as much.

Personally I hate coffee so whatever you do to it, it'll still be awful (although I love the smell so in theory I'd appreciate you adding the milk later so I get to appreciate the smell for longer!). Quite a lot of scientific effort has been spent on the old conundrum of whether to heat the tea pot first or not too.

[Lesley Silvester]

I voted that I didn't care but I still read all the posts and now I'm 

[john and helen]

the worst thing ever, has got to be, coffee made with hot milk…… i could throw up every time i see that layer of skin floating on top……. anyway…always add the milk after, as i like mine strong

[SallyintNorth]

the worst thing ever, has got to be, coffee made with hot milk…… i could throw up every time i see that layer of skin floating on top……. anyway…always add the milk after, as i like mine strong

Wouldn't it be boring if we were all the same!  Now I have the Rayburn I can make myself hot-milky coffee whenever I want   

Umm... why is it stronger if you add the milk after?  If you add the same amount of milk, surely it has the same strength whether the milk goes in first or second?  Or did you mean tea - in which case I agree, the flavour develops better if you let it steep for a few minutes before adding the milk.

[john and helen]

if you add the milk before, you may put in to much… by adding it after, you can get the right amount..nothing worse than over milky coffee ……..bluuuuuuuuu 

and over stewed tea is a big no no  as is under stewed tea …i.m sounding fussy 
and always smell the milk 1st….

[SallyintNorth]

…i.m sounding fussy 

No, really?     Do you think so?   

Many many many moons ago, I was preparing to take my then new boyfriend (later to be my husband and now unfortunately my ex-hubby) to meet my family for the first time.

I explained that we were the sort of household where, if you wanted a hot drink, you just helped yourself, and asked everyone else if they'd like one too.

And then I explained who drank what and how...

By the time I finished he had collapsed down the kitchen cupboards to the floor, literally crying with laughter and gasping for breath.