Last November, millions of Britons experienced subpar cups of tea as a result of record-breaking low atmospheric pressure caused by Storm Ciarán.
A study conducted by meteorologists at the University of Reading revealed that the boiling point of water dropped to 98°C during the storm, below the recommended 100°C for optimal tea extraction.
On November 2, the barometric pressure fell to 956.0 millibars, the lowest recorded since February 1989. This marked a significant deviation from typical conditions, as atmospheric pressure naturally declines during storms.
Caleb Miller, a PhD student and co-author of the study, set up experiments to measure boiling water properties under low pressure.
Using a standard electric kettle and temperature sensors, Miller’s team compared their findings to previous boiling points observed under varying air pressure.
They integrated weather data from roadside stations across southern England to assess the storm’s regional impact, revealing how the pressure minimum moved northeast during breakfast hours.
Alec Bennett, another co-author, noted that while the effects of pressure on boiling temperatures are known among mountaineers, Storm Ciarán showcased these phenomena across a densely populated area, leaving tea enthusiasts with less than satisfying brews.