IIT-Madras professor explains why dosas are crispy on outside & soft on inside
Dosa, a traditional South Indian dish, has been a staple in many households for centuries. The delicate balance of crispy exterior and soft interior has always fascinated food enthusiasts. Recently, Prof Mahesh Panchagnula from IIT-Madras shed light on the science behind this phenomenon. In a fascinating explanation, he revealed that the secret to achieving the perfect dosa lies in the Leidenfrost Effect, a concept identified in 18th century Germany.
For those who are unfamiliar, the Leidenfrost Effect is a phenomenon where a liquid, in this case, water, comes into contact with a surface that is significantly hotter than its boiling point. When this happens, the water droplets do not immediately evaporate. Instead, they form a thin layer of vapor between the liquid and the hot surface, allowing the droplets to glide and float on this vapor layer. This effect is named after Johann Leidenfrost, a German doctor who first observed and documented this phenomenon in 1756.
So, how does this relate to the art of making dosas? Prof Panchagnula explained that the practice of sprinkling water on a hot tawa (griddle) before pouring the dosa batter is directly linked to the Leidenfrost Effect. When the tawa is not hot enough, the water evaporates slowly, and the dosa batter sticks to the surface. However, when the tawa is heated to the right temperature, the water glides and floats on a thin vapor layer, preventing the dosa from sticking and making it crispy.
This explanation is a game-changer for dosa enthusiasts, as it highlights the importance of temperature control in achieving the perfect dosa. The ideal temperature for making dosas is between 200°C to 250°C. At this temperature range, the water droplets on the tawa create a thin vapor layer, allowing the dosa batter to cook evenly and preventing it from sticking to the surface.
But why do dosas remain soft on the inside? The answer lies in the batter itself. The fermentation process involved in making dosa batter breaks down the starches and creates a network of air pockets. When the batter is cooked on the hot tawa, these air pockets expand, creating a soft and spongy interior. The heat from the tawa cooks the exterior quickly, creating a crispy crust, while the interior remains soft and fluffy.
In addition to the Leidenfrost Effect, Prof Panchagnula also emphasized the importance of using the right type of flour in making dosa batter. The traditional recipe uses a combination of rice and lentil flour, which provides the necessary structure and texture to the dosa. The rice flour helps to create a crispy exterior, while the lentil flour adds protein and fiber, making the dosa more nutritious.
The science behind making dosas is fascinating, and Prof Panchagnula’s explanation has sparked a lot of interest among food enthusiasts. The next time you make dosas, remember to sprinkle water on the hot tawa before pouring the batter, and make sure the temperature is just right. With a little practice and patience, you can achieve the perfect dosa – crispy on the outside and soft on the inside.
In conclusion, the art of making dosas is not just about following a traditional recipe; it’s about understanding the science behind the process. The Leidenfrost Effect, temperature control, and the right type of flour all play a crucial role in creating the perfect dosa. Whether you’re a seasoned chef or a beginner in the kitchen, this explanation is sure to inspire you to experiment and innovate in the world of dosa-making.
News Source: https://x.com/iitmadras/status/1993901259925909929
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