OT (but science ...)

Good point, but...

I drink my coffee (after a small amount of milk has been added) straight away. I like it HOT...!

NOt sure how to solve this...

Why would using boiling water denature some of the components of the coffee when it has already been heated to over 200 deg C for many minutes in the roasting process?

John

I've not experimented, but does it also reduce the skin effect of water, allowing for the those smaller bits/drops?

I use a coffee machine, maybe as above - water reservoir, heating element, thermostatic switch, jug and a control which automatically switches itself off after 20 minutes. Filter, into which you measure the coffee grounds.

I always make myself two small cups at a time and take my time drinking the first one, such that it has often switched off by the time I get to pouring the second cup. My workaround, when I remember, is to switch off/on after pouring the first cup, otherwise it can be off and cooled before my second cup.

If I forget, or take too long, I pop the cup of too cool coffee in the microwave for 10 seconds to put some warmth in it. Allow too long in the microwave and the coffee ends up very bitter and horrible. Get it right and it is not too bad.

During the initial syphoning/making phase, the stat switches off and the syphoning stops for a while, which greatly extends the time it takes for it to make the coffee. Being impatient, I was considering adding a switch across the stat, so it gets the coffee brewed quicker.

Its the different saturations of other liquids or gasses in the liquid you stir.

I'd imagine if you were playing the old glasses tuned by water you need to be sure your water is at room temp before testing the pitch.

Brian

This seems to be the right explanation

Assuming you are using instant coffee the freeze drying process drives off all the volatiles before the water anyway.

If you like milk with your coffee then that is no longer a problem.

I wonder if you could genuinely taste the difference in a double blind trial, where the cup is allowed to attain the same final temperature. Taste is a function of temperature.

So what's that you smell in the cloud of vapour when you pour boiling water onto instant coffee?

Is this based on your DIY experiments in drying coffee at -40C?? If not, please cite.

SWMBO suggested (since hearing of this thread) I also drop in our experience not that long ago with a friend who insisted they couldn't drink twice-boiled water and made a point of emptying the kettle every brew.

We would have dismissed it only shortly afterwards someone in a TV programme made a similar claim.

There are two questions here, really. Does it make any difference at all (possibly due to dissolved gases ?) and even if it did, would a person be able to detect.

However it seems some people can actually smell sugar in a hot drink ?

Why boil more than they need?

Sounds a bit suspect. Perhaps they like the taste of limescale

I certainly can.

Because filling a kettle every time is a waste of time?

Instructions for making tea usually say 'freshly drawn water'. Mind you, that's for leaf tea, and all proper tea is theft.

Certainly in tea - I don't take sugar but can easily smell if tea's been sugared.

This thread reminded me that I haven't had a cup of coffee for years, I prefer tea. So I made a cup of reputable instant. Meh. I think that's it for a few more years.

And where did the modern habit of walking round sipping coffee from a plastic spout come from? Why would anyone do that?

Pure affectation.

What you have observed it that the vapour pressure of ingredients are still sufficient, despite the process of extraction, freeze drying such that elevating the temperature to boiling once more will still not have a significant effect on aroma.

The nose is a very sensitive organ, and I can detect things like sugar in coffee simply from smelling the hot beverage. What's the boiling point of sugar? The melting point alone is in excess of 180C. Do you think sugar can survive the boiling process without destroying the smell?

Do you honestly think that water is the only compound that sublimes at

-40C? And that the more volatile aromatics don't?

The -40C is chosen to primarily extract water without concern over other volatiles. The temperature of the cold finger / condenser also dictates which volatiles are drawn off the frozen mix.

Sugar starts to break down before it reaches a boiling point.

Can you please provide a cite?

It may well be the case but the structure is very stable and if there was a breakdown it would expect it be into glucose and fructose.