Is it storming, is the water boiling

Air pressure influences cooking - It storms, the water boils faster

At home, making the breakfast egg is always perfect, but during a mountain vacation, it's still runny, despite the same cooking time? The blame for this misery lies in the changed air pressure at high altitudes. But even those who prefer spending the summer at the beach are not spared such mishaps. Researchers have discovered that bad weather also influences water boiling - and thus tea, egg, and spaghetti.

Important in the preparation of these foods is the boiling point. It is usually said: water boils at 100 degrees, so it then transitions from a liquid to a gaseous state. However, this rule only applies under normal conditions at sea level, at 1013.25 hectopascals. In the mountains, water begins to boil faster, even at temperatures below 100 degrees. The rule of thumb says: every 300 meters in altitude, the boiling point decreases by one degree.

Trough or height: The physics does not distinguish

Also, low-pressure areas cause a changed air pressure. When the storm "Ciarán" passed over Great Britain in November 2023, Caleb Miller from the University of Reading's Meteorology Department quickly fetched his measuring equipment. They were able to establish a direct link between the low pressure in the morning of November 2nd and the boiling temperature. In some places, only 953.6 hectopascals were measured - and the water boiled below 98 degrees.

As the researchers describe in their study in the journal "Weather," this could possibly have affected millions of Britons in making their tea. "This is due to the fact that tea is very sensitive to the temperature of the water used for brewing, which is related to the effectiveness of the extraction of tannins from the tea." For black tea, temperatures between 98 and 100 degrees are recommended. The breakfast tea on that day was therefore likely weaker for many people.

Effects greater than expected

"How many Britons need my morning cup of tea," thought the main author Giles Harrison. "I know that the boiling point of water depends on air pressure, but I didn't expect a storm to bring the temperature of the boiling water outside the recommended range for making good tea."

Even those who wanted to cook a breakfast egg in the south of Great Britain at that time had to wait a few seconds longer than usual. The cooking time depends on the temperature. Water evaporates below 100 degrees at a lower pressure without getting any hotter. With such a reduced cooking temperature, it takes longer for the egg to set. Noodles also need more time.

No egg in the Himalayas

By the way: On the highest mountain in the world, Mount Everest, one could no longer cook an egg, explains geophysicist Roland Pail from TU Munich. "The yolk still jiggles, but the egg white starts to solidify only at 84 degrees." These temperatures would not be reached there - unless a pressure cooker was carried up. And even in an Alpine hut, the effects are relevant: "A normal egg takes 1.5 minutes to cook at sea level, but on a thousand meters in altitude, it already takes more than ten minutes."

Despite taking the same cooking time, an egg during a mountain vacation can still be runny due to the altered air pressure at high altitudes, affecting the boiling point of water.
Physics does not differentiate between a trough or height, and the boiling point of water can change significantly in the mountains, influenced by changes in air pressure.
During the passage of the storm "Ciarán" over the United Kingdom in November 2023, the low air pressure caused the boiling temperature to drop below 98 degrees, which could have affected the brewing temperature of tea for millions of Britons.
In the south of Great Britain at that time, those who wanted to cook a breakfast egg had to wait a few additional seconds due to the reduced cooking temperature caused by the lower air pressure.
On Mount Everest, the highest mountain in the world, the yolk of an egg can still jiggle, but the egg white starts to solidify only at 84 degrees, which is below the temperature necessary to cook an egg due to the extremely low air pressure.