Storms have an influence on tea preparation

At home, the breakfast egg always turns out perfectly, but on vacation in the mountains it is still flabby, despite the same amount of boiling time? The change in air pressure at high altitude is to blame for this misery. But even those who prefer to spend the summer on the beach are not immune to such incidents. Researchers have discovered that bad weather can also affect the boiling of water - and therefore tea, eggs and spaghetti.

The boiling point is important when preparing these foods. It is usually said: Water boils at 100 degrees, i.e. it then changes 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 more quickly - all other things being equal - at temperatures below 100 degrees. The rule of thumb is: for every 300 meters of altitude, the boiling point drops by one degree.

Low pressure area or altitude: physics does not differentiate

Low pressure areas also cause a change in air pressure. When the storm "Ciarán" passed over the UK in November 2023, Caleb Miller from the University of Reading's Department of Meteorology quickly got out his measuring equipment. He and his colleagues were able to establish a direct correlation between the low pressure on the morning of November 2 and the boiling temperature. In some cases, only 953.6 hectopascals were measured - and the water boiled at less than 98 degrees.

As the researchers describe in their study in the scientific journal "Weather", millions of Britons were therefore possibly unable to boil their tea properly. "This is because tea is very sensitive to the temperature of the boiling water used to make it, which is related to the effectiveness of extracting the tannins from the tea." For black tea, 98 to 100 degrees is recommended. The breakfast tea on this day was therefore probably a little weak for many people.

Effects greater than expected

"Like many Brits, I need my morning cup of tea," said lead author Giles Harrison. "I know that the boiling point of water depends on air pressure, but I didn't expect a storm to take the temperature of boiling water outside the recommended range for making good tea."

Even if you wanted to boil an egg for breakfast in the south of the UK at the time, you had to wait a few seconds longer than usual. This is because the cooking time depends on the temperature. If the pressure is lower, the water evaporates at less than 100 degrees without getting any hotter. At such a lower cooking temperature, it takes longer for the egg to set. Pasta also needs more time.

No hard-boiled eggs in the Himalayas

Incidentally, on the highest mountain in the world, Mount Everest, you couldn't cook an egg at all, as geophysicist Roland Pail from the Technical University of Munich explains. "The yolk still solidifies, but the egg white only coagulates at 84 degrees." This would no longer be reached up there - unless you dragged a pressure cooker up there.

And the effects are also relevant at a mountain hut in the Alps: "A normal Easter egg takes nine and a half minutes at sea level, and just over ten minutes at an altitude of a thousand meters."