On Fri, 4 Feb 2005 20:27:19 +0900, kuri wrote:

> "Bluesea" > wrote in message
>
>>> >WHOA! Stop right there 'cause you're scaring me. Are you aware that a
>>> >microwave oven can super-heat water beyond the 212F boiling point w/o
>>> >it ever creating a shimmer much less a bubble?
>
> No, it can't. Use your thermometer to check (I did). Microvawe is not magic.
> The bubbling occurs at the same temp. whatever you use to heat your water,
> the exception is when you do it in a pressure cooker.

Yes, it actually can. Yes, it has been documented.

A clean, smooth container in the microwave inhibits nucleation, the
transition from liquid to gas. Temperatures as high as 241 degrees
Fahrenheit have been achieved using a microwave without ever having a
bubble form. The jostling of the water when removing typically prompts
the sudden formation of bubbles, as evidenced in the boil over.

The same effect can actually be accomplished with a kettle. But most
kettles have seams in the metal, or patterns embossed in the bottom.
These are enough to prompt nucleation, so at 212/100 degrees, water
boils at sea level in a kettle.

I have "tested" several different microwaves over the years, and on
several instances, I produced a cup of water that was over 212/100
when measured with a thermometer but never produced a bubble.

However, to accomplish the "boilover" in a microwave typically
requires overcooking the water by a couple of times beyond what was
necessary to achieve a boiling temperature.

--
Derek

Hard work often pays off after time, but laziness always pays off now.