Nicole Sharp<p><strong>Pour-Over Physics</strong></p><p>Fluids labs are filled with many a coffee drinker, and even those (like me) who don’t enjoy coffee, can find plenty of fascinating physics in their labmates’ mugs. Espresso has received the lion’s share of the research in recent years, but a <a href="https://doi.org/10.1063/5.0257924" rel="nofollow noopener" target="_blank">new study</a> looks at the unique characteristics of a pour-over coffee. In this technique, coffee grounds sit in a conical filter and a stream of hot water pours over the top of the grounds. Researchers found that the ideal pour creates a powerful mixing environment in a coffee-studded water layer that sits above a V-shaped bed of grains created by the falling water jet. </p><p>The best mixing, they find, requires a pour height no greater than 50 centimeters (to prevent the jet from breaking into drops) but with enough height that the falling jet stirs up the grounds. You also want to pour slowly enough to give plenty of time for mixing, without letting the jet stick to the kettle’s spout, which (again) causes the jet to break up. </p><p>That ideal pour extracts more coffee flavor from the grounds, allowing you to get the same strength of brew from fewer beans. As climate change makes coffee harder to grow, coffee drinkers will want every trick to stretch their supply. (Image credit: <a href="https://unsplash.com/photos/a-cup-of-coffee-with-a-dog-on-it-ygAeDaLKJe4" rel="nofollow noopener" target="_blank">S. Satora</a>; research credit: <a href="https://doi.org/10.1063/5.0257924" rel="nofollow noopener" target="_blank">E. Park et al.</a>; via <a href="https://arstechnica.com/science/2025/04/the-trick-to-making-great-pour-over-coffee-with-fewer-beans/?__readwiseLocation=" rel="nofollow noopener" target="_blank">Ars Technica</a>)</p><p><a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/coffee/" target="_blank">#coffee</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/fluid-dynamics/" target="_blank">#fluidDynamics</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/granular-material/" target="_blank">#granularMaterial</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/jets/" target="_blank">#jets</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/mixing/" target="_blank">#mixing</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/physics/" target="_blank">#physics</a> <a rel="nofollow noopener" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/science/" target="_blank">#science</a></p>