An IIT-Madras professor has traced the secret of the perfect dosa to physics, arguing that the dish’s crisp exterior and tender centre are explained by an 18th-century German scientific principle.
The institute recently highlighted Prof. Mahesh Panchagnula’s work, which shows how temperature, batter consistency and technique intersect to produce the ideal dosa.
According to Panchagnula, the secret lies in controlling the heat of the tawa and understanding the Leidenfrost effect.
“The key,” he explained, “is ensuring the tawa reaches a temperature where this effect begins to work. That is when the batter spreads smoothly, lifts slightly, and crisps evenly without burning or sticking.”
The Leidenfrost effect was first observed in 18th-century Germany.
When water hits a surface that is hot enough, it does not evaporate instantly. Instead, droplets hover on a thin layer of vapour.
This keeps them from sticking to the pan.
Generations of South Indian households have applied this principle unknowingly, according to Daily Thanthi, which reported the Panchagnula’s research.
Every cook who sprinkles water on the tawa before ladling batter is running a quick, intuitive experiment. If the droplets dance, the pan is ready. If they evaporate too fast or sit still, it is not.
The ideal tawa, Panchagnula noted, allowed the thin spread of batter to cook from below while the top layer remained just moist enough to fold without cracking.
Batter matters too.
Fermentation creates tiny air pockets, he says. These expand when heated and help produce the dosa’s texture. The spread technique shapes the rest. A smooth, even spiral gives the dosa its thin, crisp structure.
The IIT-Madras post has sparked interesting conversations online.
One user wrote, “Incredible how a simple ‘water sprinkle test’ carries centuries of intuition and scientific precision. Our cuisine is smarter than we give it credit for!”
“The IIT Madras professor couldn’t find a more pressing subject to do his research. His next topics would be the vectorial effects of various condiments in the aroma of Sambhar”, wrote another.
Some defended the effort. “Physics and Chemistry exist in everything in day to day life, as they form the cornerstone of what we see around us. Individual skill, here Culinary instinct decides when to pour the batter on the griddle and get a crispy dosa.”