芯 (core, heart)

[katafei]

I have a question about the meaning of 芯 (core, heart) in this sentence:

高山の頂上で飯を炊くと、気圧が低いので水が１００度以下で沸騰してしまい、芯のあるめしになる、ということの逆の現象がおこるわけだ。湯の温度が１１０度とか１２０度になる。

It's from a piece of writing in which the function of a pressure cooking is explained by using the comparison of cooking on the top of a mountain, where air pressure is low and therefor the boiling point of water is low.
But to what is 芯のあるめしになる referring?
Surely not the core of the mountain? Cooking inside a mountain makes no sense...no matter why the comparison is made...so I'm guessing I misunderstand this bit.....

[phreadom]

Well, I can't really understand most of it.. but 芯のあるめし says it means "undercooked rice" and になる means "will turn out" or "will become" etc... so my guess is that it would be something about having to adjust the cooking time or pressure, lest your rice come out undercooked?

I'd have to try a lot harder to work out more of the paragraph and get any better of an idea. But as a beginner it's a bit over my head.

[katafei]

芯のあるめし says it means "undercooked rice"

ah, that does shed some light ^^ thanks

[Yudan Taiteki]

It's actually the reverse; the following ということの逆の現象がおこるわけだ means "...the opposite of this phenomenon [i.e. the 芯のあるめし] happens." The outside of the rice becomes hard because of too much cooking, rather than the inside being hard because of not cooking enough.

[NileCat]

It's actually the reverse; the following ということの逆の現象がおこるわけだ means "...the opposite of this phenomenon [i.e. the 芯のあるめし] happens." The outside of the rice becomes hard because of too much cooking, rather than the inside being hard because of not cooking enough.

Well...it's a little bit different.
Your understanding about the sentence structure is perfect.
But, meaning-wise,
"the opposite of this phenomenon" doesn't mean "the outside of the rice becomes hard" here.
It's just implying "it cooks quickly" or "it can easily be overcooked".

EDITED