As I pointed out, there are also some ionic solids, such as Na[sub]2[/sub]SO[sub]4[/sub] which are less soluble in hot water than cold.
Actually, the solids and gasses thing isn’t counterintuitive at all, if you think of “going from solid to liquid” as being sort of like melting, and “going from gas to liquid” as being sort of like condensation.
Again, granting that there are a few exceptions.
>Purifying water by boiling it reduces the number of viable bacteria present. It will never sterilize the water.
In studying steam sterilization I think I read that there is a required time at the boiling point that will sterilize water, though certainly it is not zero (that is, the requirement is much more stringent than just getting up to the boiling point temperature). I also think the time I remember is 20 minutes, though your 15 minutes at 250 makes me think the time at 212 would have to be much longer than 20. So, “never”? Are there bacteria that would survive a week?
"The most heat-tolerant hyperthermophile is the recently-discovered Strain 121[1] which has been able to double its population during 24 hours in an autoclave at 121°C (hence its name).
Although no hyperthermophile has yet been discovered living at temperatures above 121°C, their existence is very possible (Strain 121 survived being heated to 130°C for two hours, but was not able to reproduce until it had been transferred into a fresh growth medium, at a relatively-cooler 103°C). However, it is thought unlikely that microbes could survive at temperatures above 150°C, as the cohesion of DNA and other vital molecules begins to break down at this point."
from Hyperthermophile - Wikipedia
Color me astounded that life is actually able to survive in an active form at temperatures above boiling. Boiling-resistant spores are impressive enough, but reproducing?
That’s not entirely accurate. Increasing the pressure doesn’t change the fact that the boiling point is the hottest water can get; it just raises the boiling point.
However, pure, distilled water in a smooth container can be heated a little beyond the boiling point. The lack of nucleation points prevents bubbles from forming; this allows the water to continue to heat, rather than the normal case, where extra energy merely makes the water boil faster. This is the cause of the occasional cases you will here of of “exploding” water.
Yes, “superheating” is what I was thinking of when I said “special conditions.” I’m pretty sure that it doesn’t require distilled water, just a lack of nucleation points. There are occasional reports of people managing the trick (usually accidentally and with moderately unfortunate consequences) using just tap water in mug in the microwave.
The phenomenon that we’ve all seen of instant coffee crystals causing a microwaved cup of water to erupt has something to do with this, right? It’s been discussed here within the past few months, but I can’t remember in what context.
That’s nothing, I can’t find the link (it was a Nature podcast a couple of years ago), but bacteria have been found which can function in liquidified gases! I don’t remember the exact temperture, but, IIRC, it was liquid nitrogen, and while the critters were slowed down, they were still reproducing.
while I can’t agree that reproducing at 121C is nothing, reproducing at LN2 temperatures is even more amazing. I mean, how did the microbes practice (evolve) for that? Obviously they did not-it is just an incidental benefit of some other trait. But still-it is way cool! 
Boiling is not the optimum temperature for brewing ground coffee. I think it’s somewhere around 180-190 F. Hotter than that and you get more bitter coffee.
I notice that you live near Yellowstone National Park. Go there and you can see the bacteria that live in boiling temperatures in action–they are what cause a lot of the beautiful colors in the hot springs.
Again, condition dependant. For those of us that live at high altitude, boiling IS right around those temperatures…especially by the time the water heats up the grounds and the french press.
Vigorous boiling keeps noodles etc. from becoming starchy lumps, instead of individual units of pasta-y goodness.
Exactly. The water is superheated and the addition of coffee or whatever provides a large number of nucleation sites in a very short time. Each of which trigger a flash-to-steam event & the water comes bursting up out of the cup. For further Googleage (great coinage upthread), the magic terms are superheat & nucleation.
Most of those actually live at just slightly below boiling, though, which is in turn a bit below 100 C due to altitude. These hyperthermophiles are well above boiling, and I’m hard-pressed to think what environment they could have evolved in to develop that.
Seafloor hydrothermal vents.
That’s true. And you’re right that the boiling water at Yellowstone is cooler than sea level boiling water, although I guess it never clicked with me before that that could be why they are able to survive there.
I grew up near Bozeman, in Manhattan, MT, which is a bit lower elevation (Wikipedia says 4245 ft.) In science class, we once measured the boiling point of water, and it was, IIRC, 206 degrees F.