Millions of Britons were forced to drink substandard cups of tea last November due to the record-breaking low pressure caused by Storm Ciarán.
The low pressure caused the boiling point of water to drop below the 100C temperature that some experts recommend to extract the full flavor from tea leaves.
The study by meteorologists at the University of Readingpublished in the journal Weer, reported that the water in Reading was boiling at 98C on the morning of the storm.
For water to boil, the atmospheric pressure must match the vapor pressure of the liquid. It is normal for atmospheric pressure to drop during bad weather such as storms.
On the morning of November 2, Caleb Miller, a PhD student and co-author of the study, set up his equipment in the meteorology department’s laboratories to measure the boiling point.
“As an experimental person, I saw the opportunity to make some measurements of the properties of boiling water at low atmospheric pressure,” Miller said.
By conducting controlled experiments with temperature sensors and a standard electric kettle, Miller and his team were able to compare the results with previous boiling points observed under different air pressure conditions using the same apparatus.
To assess the wider regional effect of the storm on boiling points, they also combined weather data from various resources, including roadside weather stations across southern England and pressure readings from the Read University Atmospheric Observatory.
This allowed them to monitor how the pressure minimum moved northeast across the region during the morning, coinciding with typical breakfast times.
Such effects are rarely seen in densely populated areas. Alec Bennett, a co-author of the study, said: “The effect of pressure on boiling temperatures has long been known to mountaineers, but Ciarán brought the effect to a wide region.”
