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Article by
Linda Stradley
of
What's Cooking America.
Also check out:
Poaching vs. Simmering vs. Boiling
Boiling Points of Water
From the book Kitchen Science by Howard Hillman
Salt: Salt, sugar, and practically any other substance elevates the boiling point
and therefore shortens cooking time. The difference in temperature between unsalted and salted water (one teaspoon of salt per quart of water) is about 1° to 2° F, a difference that can be critical in cooking
situations demanding exactness.
Hard Water: Hard water defines water with a high level of dissolved mineral salts. Therefore, hard water boils at a higher temperature. The difference in the boiling point between typical supplies of hard and soft
water is about a degree or two.
Alcohol:
Alcohol has a lower boiling point that water (about 175° F as compared with 212° F). If you dilute water with alcohol, the mixture will have a lower boiling point up until the
alcohol completely evaporates. Should you decide to alter an existing recipe by substituting a fair portion of wine for some of the water, remember to extend the cooking time
by 5 to 10 percent depending on the alcohol strength of the wine and the heaviness of your touch.
Weather:
The boiling point of water is a degree or two lower on stormy, as opposed to fair, weather days. Consequently, boiled food will take longer to cook on a stormy day.
Different
Size Pans: Will a given volume of water boil at a higher temperature in a tall, narrow pot than in a short, wide one? Yes. since the tall, narrow pot has a great depth,
its bottom-lying water is under greater pressure from the water above it than is the water at the bottom of the short, wide pot. The greater the pressure, the high the boiling point.
The difference is approximately 1° F.
Altitude:
The higher the altitude, the lower the atmospheric pressure. The less atmospheric pressure that bears down on the surface of the liquid, the easier it is for water molecules to escape into the air.
Thus, the water comes to its full rapid boil at a lower temperature in the mile-high city of Denver than it can in coastal Miami. For each thousand feet above sea level,
the boiling point of water drops almost 2° F.
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How To Boil Water:
 Boiling water is very easy to do, but it is crucial to many meals, such as cooking rice and
Pasta.
Choose
a pot that's large enough to hold the amount of water
you want to boil, and has a lid that fits.
You might be
tempted to use water that's already warm or hot from the
tap, but this water has been sitting in your pipes for
some time, getting stale. Use cold water if you're going
to drink it or cook with it.
Don’t fill the pot all the
way up. Keep in mind that anything you add to the
boiling water will increase the volume, and plus, you’ll
need to allow room for those bubbles to do their thing. Without enough room in the pot, for example, rice or
pasta will boil over.
Place the pot on the stove
and turn the heat to high. If you want to speed up the
process, put a cover on it
Check for steam escaping from under the lid, then lift the lid
carefully to see how the water is doing.
Look at the water. If large bubbles are rising from the
bottom of the pot to the surface, the water is boiling.
NOTE: Small bubbles that stay at the bottom or sides of
the pot are air bubbles present in the water; they don't
necessarily indicate that boiling is imminent. Wait for
bubbles that rise to the top of the pot.
High Altitudes:
Water will boil at high
altitudes, but it isn't as hot as boiling water at sea
level. This is because the air pressure is lower at high
elevations. Boiling occurs when the water is hot enough
to have the same pressure as the surrounding air, so
that it can form bubbles. At high altitudes, air
pressure is lower than at sea level, so the water
doesn't have to get so hot to get to boiling.
Because
the temperature of the boiling water is lower at high
elevations than at sea level, it takes longer to cook at higher altitudes than at sea level.
The speed that food cooks is not related to the time it
takes to boil.
Adding a little salt to
the water will cause the water to boil at a slightly
higher temperature which can be helpful while cooking
especially at high altitudes.
Temperatures of water:
Approximate Boiling
Temperatures of Water
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Altitude |
Temperature |
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Sea Level |
212 degrees F |
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984 ft. |
210 degrees F |
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2,000 ft. |
208 degrees F |
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3,000 ft. |
206 degrees F |
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5,000 ft. |
203 degrees F |
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7,500 ft. |
198 degrees F |
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10,000 ft. |
194 degrees F |
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20,000 ft. |
178 degrees F |
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26,000 ft. |
168 degrees F |
High Altitude: Water boils at less than 212°F (approximately
96°F). Each 500 foot increase in altitude causes a drop of about 1° in the boiling point.
Sea Level:
Water boils at 212°F and simmers at 190°F.
Tepid Water - 85 to
105°F. The water is comparable to the temperature of the human body.
Warm Water
- 115 to
120°F. The water is touchable but not hot.
Hot Water - 130 to
135°F. The water is too hot to touch without injury.
Poach - 160 to 180°F.
The water is beginning to move, to shiver.
Simmer - 185 to 200°F.
There is movement, and little bubbles appear in the
water.
Slow boil - 205°F.
There is more movement and noticeably larger
bubbles.
Real boil - 212°F. The
water is rolling, vigorously bubbling, and steaming.
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