Jumping kettle

Limescale?

Could be.

Will it lose significant power transmission if you put a sheet of paper underneath it? Or, a bit thicker, but providing more damping, a piece of that sort of silicone fabric sheet that can be put in the bottom of ovens to make cleaning easier?

Its urm, Kettling then, has it got a build up of lime scale inside it, Not sure how efficient a device might actually be!

Brian

Mike Halmarack has brought this to us :

Limescale, you can buy descaler tablets and powder fairly cheap.

Use heavy water instead of ordinary tap water ?

We have very, very soft water here, but I have descaled a badly coated kettle in a rented holiday home by boiling vinegar in it. Followed by washing out and boiling water a few times.

Probably, though I have one of those steel mesh balls inside the kettle plus a nice round beach pebble that grandma used in her kettle.

I'll try the vinegar method suggested, or other descaler

That sounds like intersting fun. I'll have to give that a try.

Would that save on electricity as well?

Thanks, I was considering using Harpic but that would perhaps be recklessly frugal.

Kettling, yes, that sounds about right

It's strange, as a kid I used to take a bottle to the local grocer and get it filled with vinegar, then drink some on the way home. Now, when pickling is going on in the kitchen, I have to get out of there.

No, you'd use more electricity. The thermal capacity of heavy water is higher: it takes more energy to get them heavier deuterium atoms moving. And the boiling point is higher.

You need an acid, rather than Harpic which will be alkaline.

Vinegar may not be to your liking but is safe. Perhaps ensure lots of ventilation?

You might get better tea because of that, though!

Quite so. I knew astronomers in the 70s who drafted a grant application for heavy water for making tea when observing at 3000m.

Is it really worth it for a difference of 1.4 deg C (H2O=100, D2O=101.4 degC)? Those are figures for sea-level atmospheric pressure. Does the difference in BP between H2O and D2O become more pronounced as atmospheric pressure is reduced?

At least they didn't suggest using tritiated water (tritium rather than deuterium) because that is both radioactive and corrosive "due to self-radiolysis".

It is a well-recognised problem in mountaineering. It would be quite nice to do some tests on tea made at different temperatures in a pressure cooker, but it is a bit difficult to control the "steeping time". It does strike me as being quite a nice DIY project.

"Experts" seem to claim that only black tea needs brewing at 100 deg C, but that this is too hot for "finer" teas. It seems strangely convenient if standard boiling point is just right for black tea (although perhaps the drying conditions have been optimised for that).

I know about the problems of getting the water hot enough at high altitudes. I'd wondered about a pressure cooker, but it would need a way of venting the pressure quickly (*) so the teabags/strainer could be removed at a defined time. I wonder if the most controllable results are to heat the water so it boils at (reduced) atmospheric pressure, add the tea, put on the lid and heat it as fast as possible so it boils again at sea-level pressure as quickly as possible, then start timing.

I presume there is the same problem with making tea on an aircraft which typically has a cabin pressure that is equivalent to about 6000 feet. Mind you, they probably use instant tea powder - which is about as palatable as instant coffee ;-)

Don't have the problem with (real) coffee. That is best made with water which is about 70 degC, to avoid "scorching" the coffee grounds.

Apparently D2O has a slightly different flavour to H2O (eg when drunk cold), and that might impart a noticeable flavour to tea made with it.

(*) Use a long stick to "pop" the safety valve from a safe distance to avoid getting scalded by the steam?