higher until the phase change from liquid to
gas has been completed.
The Boiling Point Depends on Elevation The
boiling point of water is constant given a
constant physical environment, but it varies
from place to place and even in the same
place. The boiling point of any liquid depends
on the atmospheric pressure bearing down on
its surface: the higher the pressure, the more
energy it takes for liquid molecules to escape
the surface and become a gas, and so the
higher the temperature at which the liquid
boils. Every 1,000 feet/305 meters in
elevation above sea level lowers the boiling
point about 2ºF below the standard 212ºF (or
1ºC below 100ºC). And food takes longer to
cook at 200º than it does at 212º. Even a low-
pressure weather front can lower the boiling
point, or a high-pressure front raise it, by as
much as a degree or two.
Pressure Cooking: Raising the Boiling Point