WHEN THE PRESSURE IS ON
Dr. James Merritt
1. Is there anybody here under pressure? Do you ever
feel like you live in a pressure cooker? Did you know
that it takes longer to cook food at high altitudes,
because at high altitudes the air pressure is much
lower than in the lower plains? Because of that the
boiling point of water is lower, and therefore it
takes much longer to cook food.
2. But in a pressure cooker high pressures are built
up within the vessel, which raises the boiling point
of water, and food can be cooked within minutes.
3. In fact, the principle of pressure-cooking is
really fascinating. Because a pressure cooker is
airtight, pressure builds up inside the pressure
cooker as the liquid inside comes to a boil. The
steam that is trapped inside causes the internal
temperature to rise beyond what it would be capable of
doing under normal room pressure. Food then cooks at
a higher temperature, and because it's under pressure
it cooks even faster.
4. At sea level (where the normal atmospheric
pressure is 14.7 pounds per square inch) the boiling
point of water is 212°F, the highest temperature which
can be reached by water at that elevation. But that
boiling point is raised 38º F to 250º F, under the 15
additional pounds of pressure that can be obtained in
a pressure cooker.
5. But I learned something else fascinating about a
pressure cooker, and that is pressure-cooking can help
you maintain a healthier lifestyle. First of all, it
uses only 1/3 the energy of normal cooking methods,
and because very little water is used in pressure
cooking, and because the pressure cooker is a "closed
system," few vitamins and minerals are lost to the
cooking water, or dissipated into the air. Vegetables
are not exposed to oxygen, and therefore they retain
their vitamins, minerals, and color.
6. In fact, the cooking times for most foods in ...
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