Ever Wondered Why Your Dosa Is Crispy Outside And Soft Inside? IIT Madras Explains The Science Behind It

Last Updated:November 28, 2025, 12:52 IST

IIT Madras explains that this simple step is connected to the Leidenfrost Effect, a phenomenon discovered by an 18th-century German physician.

A new post online is capturing widespread attention by shedding light on something most people never stop to think about. Everyone loves a dosa that’s perfectly crisp on the outside and soft on the inside, but few understand the science behind this delightful texture.

The post reveals that the secret goes beyond mere cooking technique. It’s tied to a centuries-old scientific principle that Indians have been using instinctively, without even realising it.

IIT Madras Explains The ‘Science Behind Dosa’

IIT Madras shared the post that started the discussion on X (formerly Twitter). It says, “Ever wondered why a dosa turns out perfectly crispy on the outside and soft inside? The secret goes far beyond culinary instinct driven by physics.” The institute added that one of its professors, Mahesh Panchagnula, wrote an article for DT Next explaining the idea in simple terms.

According to the post, the familiar practice of sprinkling water on a hot tawa before pouring the batter has a fascinating scientific basis. IIT Madras explains that this simple step is connected to the Leidenfrost Effect, a phenomenon discovered in 18th-century Germany. Interestingly, Indian families have been applying this effect in their kitchens for generations, all without knowing its scientific name.

The post explains that if the pan is not hot enough, the water stays in place and slowly evaporates. But when the temperature is perfect, the droplets slide on the surface because they float on a thin layer of vapour.

IIT Madras says this same effect stops the dosa batter from sticking and helps it spread smoothly, which later gives it that nice crispy edge. “So the next time you hear that sizzle, remember: making the perfect dosa is not just tradition, it’s a brilliant interplay of temperature, vapour, and technique.”

‘Every South Indian Grandma Reading This’

Shared on November 27, the post has crossed 47,000 views and has led to many reactions. A user said, “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 on the aroma of Sambhar. IIT-M was a world-class institution. Third Class “Professors” have ruined that.”

Another person joked, “Every South Indian paati (grandma) reading this like ‘cute that Germany discovered it, we just call it Tuesday morning.’”

Someone else wrote, “Only a Tamilian will propose these theories to get a publication and money. It all depends on the batter. If the batter is bad, everything will stick in every temperature.”

Another user said, “Physics and Chemistry exist in everything in day-to-day life… Individual skill, here, Culinary instinct decides when to pour the batter on the griddle and get a crispy dosa. Not just physics…need to complement it with skills.”

A person also remarked, “Incredible how a simple ‘water sprinkle test’ carries centuries of intuition and scientific precision. Our cuisine is smarter than we give it credit for!”

What Exactly Is The Leidenfrost Effect and Examples

The Leidenfrost effect occurs when a liquid touches a surface far hotter than its boiling point. At such temperatures, the bottom layer of the droplet vaporises instantly and forms a thin cushion of vapour. This vapour layer lifts the droplet slightly, preventing direct contact with the surface. Instead of evaporating immediately, the droplet skates, glides or “dances”.

That same effect we see when a few drops of water sizzle and dart across a super-hot frying pan is also the secret behind crispy dosas. When a tawa is at the right temperature, water droplets dance, and that tells cooks the pan is perfectly hot for the batter to spread evenly without sticking.

Hot cooking pan: When you splash a little water on a very hot pan, the droplets don’t evaporate instantly. Instead, they wobble, skate and swirl around, a classic sign of the Leidenfrost effect.

Pressure cooker lid: After cooking, a very hot metal lid causes water droplets to glide instead of sticking. A thin steam layer forms underneath, making them move around easily.

Clothes iron: Sprinkling water on an overheated iron causes droplets to zip around rather than soak in. The iron’s heat instantly creates a vapour cushion that lifts the droplet.

Buzz Staff

A team of writers at News18.com bring you stories on what’s creating the buzz on the Internet while exploring science, cricket, tech, gender, Bollywood, and culture.

A team of writers at News18.com bring you stories on what’s creating the buzz on the Internet while exploring science, cricket, tech, gender, Bollywood, and culture.

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