24/09/2026
It is interesting what one can find if have some kind of lasers and also point them to coffee.
https://www.facebook.com/share/p/1CbF9MMkjH/?mibextid=wwXIfr
☕ Physicists have found a simple way to make stronger pour-over coffee while using up to 10% fewer beans.
Researchers at the University of Pennsylvania studied how the flow of water through coffee grounds affects extraction.
Because real coffee is opaque, they first replaced the grounds with transparent silica gel particles inside a glass cone.
Using lasers and high-speed cameras, they watched how a stream of water disturbed the particles.
They found that pouring water from higher up — while keeping the stream smooth and unbroken — created tiny “avalanches” inside the coffee bed.
These avalanches stirred the grounds more effectively and helped water reach deeper into the bed.
That improved mixing means more flavour and dissolved coffee compounds can be extracted from the same amount of beans.
The team then repeated the experiments with real coffee and measured the amount of dissolved material in the final brew.
They found that changing pour height and flow rate could increase extraction enough to maintain similar coffee strength while using around 10% fewer grounds.
The best results came from a relatively thick, steady stream, such as the one produced by a gooseneck kettle.
But pouring from too high can cause the stream to break into droplets, reducing the mixing effect.
So the researchers recommend pouring from as high as possible while the water still forms a continuous stream.
This does not mean there is one perfect recipe for everyone.
Grind size, roast, water temperature and personal taste still matter.
But the study shows that fluid physics alone can make pour-over brewing more efficient — meaning a small change in technique could help people get more from every bag of coffee.
📃 RESEARCH PAPER
📌 Park et al., “Pour-over coffee: Mixing by a water jet impinging on a granular bed with avalanche dynamics”, Physics of Fluids (2025)
