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The perfect cup of coffee is more than just a routine, it's a science. Researchers at the University of Pennsylvania used fluid mechanics to uncover the ideal pour-over technique, revealing how simple adjustments can transform your brew. From the optimal pouring height to the importance of water flow, this gallery breaks down the groundbreaking discoveries that maximize flavor while minimizing coffee waste.
Whether you're a casual drinker or a coffee enthusiast, click on for how to take your brew to the next level.
Researchers at the University of Pennsylvania set out to find the best pour-over coffee technique, using fluid mechanics to extract the most flavor from the fewest beans.
Using a gooseneck kettle and pouring from a height creates an "avalanche" effect in the coffee grounds, maximizing contact and improving extraction for a richer brew.
This technique allows coffee drinkers to use fewer beans while still extracting robust flavor, especially helpful during times of rising coffee prices and tighter budgets.
Bad weather and rising tariffs in coffee-producing countries like Brazil and Colombia have driven up coffee prices, making daily coffee feel more like a luxury than a routine.
This newly published coffee-brewing method could help people make their grounds go further, thanks to curious physicists and fluid mechanics experts who just really love their coffee.
The idea started informally around the lab's coffee table, where researchers began wondering how to get the most flavor from minimal coffee during casual conversations and caffeine breaks.
The findings were officially published in a journal called Physics of Fluids, under the title: 'Pour-over coffee: Mixing by a water jet impinging on a granular bed with avalanche dynamics.'
While others were admiring latte art, these scientists turned their focus to the underlying mechanics of coffee preparation, looking beyond aesthetics to improve taste and efficiency.
Professor Arnold Mathijssen explained to USA Today that the coffee experiments began casually at the lab's shared coffee station, a bench corner where science and caffeine collided daily.
What started as casual tinkering with pour techniques soon evolved into structured experiments, meticulously recorded in a lab notebook by a team of highly caffeinated scientists.
The team moved to a better-equipped lab bench to control variables like pour height and water stream. The aim was simple: find out what was happening inside the filter.
Coffee grounds are opaque, making observation difficult. To understand what was happening, they needed to simulate coffee grounds with see-through materials, and some clever optical tools.
The team built a clear pour-over filter filled with silica gel, illuminated it with a laser sheet, and captured the pour with a high-speed camera to study fluid behavior.
Using custom Python and Matlab code, they analyzed how the water jet interacted with the simulated coffee bed. The goal: understand how movement affected extraction efficiency.
Their findings revealed that pouring from a higher height caused a granular "avalanche," stirring the grounds and exposing more of them to water, key for flavor extraction.
Longer contact between water and coffee grounds improves flavor. But the pour must be just right. Too slow, and water may not mix evenly with all the grounds.
A very slow pour can result in under-extracted or over-extracted coffee. Balanced water flow is essential for a cup that tastes rich, not bitter or weak.
Pouring from a greater height increases the velocity of water, triggering the ground avalanche. This movement ensures maximum surface area contact and a more even extraction.
Pouring too high or too slowly can cause the stream to break into droplets. A broken stream stops the avalanche, leading to uneven flavor extraction.
To achieve a continuous pour, aim for a laminar stream, which is a smooth, unbroken flow. It's the secret to activating the avalanche and optimizing extraction during pour-over.
A gooseneck kettle helps control the pour rate and stream thickness. It's the easiest way to produce a steady, laminar stream for a perfect pour-over experience.
Experiments showed that a slow, controlled pour resulted in the most flavorful coffee. The stream's behavior affects the entire brewing process, and ultimately, the taste.
To measure extraction, scientists evaporated brewed coffee and weighed the remaining dissolved solids. This showed how the pour method directly affected how much coffee made it into the cup.
Though the lab's usual work includes bacterial behavior in fluid flows, this experiment adds to scientific knowledge in a very delicious and relatable way: making better coffee.
During COVID-19, with their lab closed, the team pivoted to food science. Kitchen experiments kept their curiosity alive and even led them to publish research in culinary fluid mechanics.
The lab now uses coffee science to engage local students in physics. Their kitchen science outreach program makes complex ideas fun and accessible through relatable experiments.
Previous research focused on fluid behavior in espresso machines and French presses. But pour-over remained largely unexplored, until now, thanks to these coffee-loving physicists.
As far as the team knows, this is the first scientific analysis of pour-over technique using fluid dynamics. Your morning brew may never be the same again.
Sources: (USA Today) (New Scientist)
See also: Coffees from around the world you will want to try
The science behind brewing the perfect cup of coffee
Here's how to pour smarter and sip better
FOOD Drinks
The perfect cup of coffee is more than just a routine, it's a science. Researchers at the University of Pennsylvania used fluid mechanics to uncover the ideal pour-over technique, revealing how simple adjustments can transform your brew. From the optimal pouring height to the importance of water flow, this gallery breaks down the groundbreaking discoveries that maximize flavor while minimizing coffee waste.
Whether you're a casual drinker or a coffee enthusiast, click on for how to take your brew to the next level.