IIT-Madras professor explains why dosas are crispy on outside & soft on inside
Dosa, a popular South Indian dish, has been a staple in many Indian households for centuries. The delicate balance of crispy exterior and soft interior has always been a topic of interest among food enthusiasts. Recently, Prof Mahesh Panchagnula from IIT-Madras shed light on the science behind this phenomenon, revealing the secret to achieving the perfect dosa texture.
The practice of sprinkling water on a hot tawa before pouring dosa batter is a common technique used by chefs and home cooks alike. However, few people know that this practice is linked to a fascinating scientific concept known as the Leidenfrost Effect. Identified in Germany in the 18th century, the Leidenfrost Effect explains the behavior of liquids when they come into contact with a surface that is significantly hotter than the liquid’s boiling point.
According to Prof Panchagnula, when the tawa is not hot enough, the water sprinkled on it evaporates slowly, resulting in a sticky surface that can cause the dosa to adhere to the tawa. However, when the tawa is heated to the right temperature, the water glides and floats on a thin vapor layer, creating a non-stick surface that allows the dosa to cook evenly. This is where the Leidenfrost Effect comes into play.
The Leidenfrost Effect states that when a liquid comes into contact with a surface that is significantly hotter than the liquid’s boiling point, it creates a thin layer of vapor between the liquid and the surface. This vapor layer acts as a cushion, allowing the liquid to move freely and reducing friction between the liquid and the surface. In the case of dosa making, this effect prevents the dosa batter from sticking to the tawa, resulting in a crispy exterior and a soft interior.
So, how does this effect contribute to the crispy exterior and soft interior of a dosa? When the dosa batter is poured onto the hot tawa, it comes into contact with the thin vapor layer created by the Leidenfrost Effect. This layer allows the dosa to cook evenly and prevents it from sticking to the tawa. As the dosa cooks, the heat from the tawa causes the batter to dry out and crisp up on the outside, while the inside remains soft and moist.
The key to achieving the perfect dosa texture lies in the temperature of the tawa. If the tawa is too hot, the dosa will burn on the outside before it has a chance to cook through. On the other hand, if the tawa is not hot enough, the dosa will stick to the surface and fail to develop the desired crispiness. By sprinkling water on the hot tawa and creating a non-stick surface, chefs and home cooks can achieve the perfect balance of crispy exterior and soft interior.
In addition to the Leidenfrost Effect, other factors such as the type of batter used, the ratio of ingredients, and the cooking time also play a crucial role in determining the texture of a dosa. However, the practice of sprinkling water on a hot tawa remains a crucial step in achieving the perfect dosa texture.
In conclusion, the science behind the crispy exterior and soft interior of a dosa is more complex than one might think. The Leidenfrost Effect, identified in Germany in the 18th century, plays a significant role in creating a non-stick surface that allows the dosa to cook evenly and develop the desired texture. By understanding the science behind dosa making, chefs and home cooks can refine their techniques and create the perfect dosa that is sure to delight the taste buds.
For more information on this topic, you can visit the following link: https://x.com/iitmadras/status/1993901259925909929
News Source: https://x.com/iitmadras/status/1993901259925909929
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