Delhi, NCR
Sitting at the dining table and looking at the dish, Arka frowned and said, “Just water, only water, seeing it, my heart has grown faint...”
Riya was playing a game on her mobile. Without stopping the game, she absentmindedly remarked, “Are you planning to sail across the sea, Arka da? Where did you find water?”
“Right here, the dish is floating in water today. What kind of dish it is, it’s impossible to tell from the top. Jyotsna Di seems completely distracted these days. Who knows why she’s always in such a hurry? I see she’s made bread in a casserole. But even though you’re a Dilliwali, if you can finish the famous line of Bengali literature I’m quoting, I’ll treat you to mutton rezala and paratha at Aminia, guaranteed.”
“The next line is— seeing it, my heart has grown faint. Did I get it right? It’s written by Rabindranath, taken from Debotar Grash. I may not be as ignorant about Bengali as you think. So, the treat at Aminia is definitely in my destiny.”
Arka shouted, “Absolutely, absolutely. You got it right. Then we’ll head out together tomorrow afternoon.”
Riya put down her mobile on the table. Then she scooped up some of the dish with a spoon, surveyed it with a scrutinizing eye, and said, “Hmm. This is broccoli, peas, and potato curry. But each vegetable looks like a submarine sinking in the water.”
“You’re right. Whatever it is, let’s just eat it. I have to attend a dry seminar today. I’m in a bit of a hurry. You’ll get bored if you come along. Better you lie down and keep thinking about your exam results. Or maybe write a book on the hundred and eight ways to become a scientist.”
Arka’s words annoyed Riya, “Couldn’t you just avoid loading my mind with the burden of exam results again? Ever since I’ve come to Kolkata and fallen under your influence, it feels like I have no choice but to study nutrition.”
“Utter lies. I feel like drowning you in this watery dish right now. I’ve told you about the science behind cooking. But did I ever say that you can’t do research in the world of physics and chemistry?
Never mind, let’s drop the nonsense. Instead of eating this waterlogged curry with bread, answer some of my scientific questions. If you pass, a round of puchka at Gariahat is guaranteed. So, tell me, how much water is there on Earth?”
“I’ve read since childhood that the Earth is three parts water and one part land. However, 70% of the Earth's surface is covered by water, while the remaining 30% is visible land. 96.5% of the water is in the oceans, and that water is salty. The remaining 3% of the water is trapped in glaciers, clouds, and underground, and that water is fresh. Next question.”
“Very good! Now tell me, how much water is in raw food ingredients?” Arka asked, pausing his eating and looking at Riya for the answer.
“Most vegetables generally contain 70-80% water by weight. Meat has slightly less.”
“Correct answer. You’ve earned your puchka. You can eat as many as you want. Now, no more questions for puchka, but a question about cooking. Why do we add water when cooking?”
“You don’t need water when frying. But if you’re cooking vegetables or meat, it will burn without water, so…”
“Of course. But the reason it burns needs to be examined closely. The pots and pans we cook in are made of metal, like aluminum or iron. When you place a pan on the stove, it heats up quickly because metal is a good conductor of heat. That heat doesn’t immediately spread to the vegetables in the pan. So, the outer layer of the vegetables in contact with the pan gets hotter, and those parts burn if we don’t stir. Even if you stir, the heat from the stove doesn’t evenly distribute throughout the vegetables. Air stays in contact with the food, and air is a poor conductor of heat. But when you add water to the cooking process, everything stays in order. Water absorbs heat from the metal pan and distributes it evenly to the vegetables because there’s nothing like water for conducting heat through convection. Additionally, water can control the temperature. Since the boiling point of water isn’t more than 100 degrees Celsius, the temperature in the pan remains below that.”
“And when you cook in a pressure cooker, the boiling point of water increases because the pressure in the cooker rises, which also raises the temperature,” Riya remarked knowledgeably.
“Bravo! No one will be able to stop you from getting good results. Because the temperature rises, cooking in a pressure cooker is faster. However, the taste of food cooked in a pan differs from that cooked in a pressure cooker. That’s why it’s better not to cook meat in a pressure cooker.
Water has a special property, which is its specific heat. You studied this in your science books when you were younger…”
Riya interrupted Arka, saying, “Water has the highest specific heat. That’s why it takes longer to heat up compared to other liquids. For any metal, this specific heat is much lower, so it takes longer to absorb heat from a pan made of iron or aluminum.”
“Good girl! Because of its high specific heat, even though cooking takes time, the vegetables don’t burn. Now let’s talk about another property of water. A water molecule contains two hydrogen atoms and one oxygen atom, which even school children know. Due to the structure of the water molecule, the hydrogen atom side is positively charged, while the oxygen atom side is negatively charged. We know that oxygen is a master at stealing electrons. So, in the presence of heat, it snatches electrons from other proteins or chemical compounds, causing some amazing reactions. As a result of these reactions, compounds like ketones are formed in the food. A twelfth-grade student knows that ketones have various smells. The presence of these ketones in the cooking pan alters the taste of the food. And on the other hand, cooking with purified water makes it easier to preserve different chemical compounds in the food.”
“But Arka da, when cooking, after adding spices to the vegetables, water isn’t added immediately. The cooking is first sautéed until it has a bit of an oily texture, and only then is water added. Why is that?”
“Very good question. First, we add a little oil to the pan and then add the vegetables. The vegetables are lightly fried. Then the spices are added. The raw vegetables absorb the oil first because they have numerous capillary tubes on their surface. You’re surely familiar with capillaries—tiny, invisible tubes through which water and other minerals circulate in living plants. The oil enters these tubes. Then, as the heat in the pan increases, the tissues of the vegetables break down. As a result, the walls of all the cells break, and the oil and water mix together. The sizzling sound in the pan is because oil and water don’t mix. How could they? Water is polar, and oil is a non-polar compound—meaning the first one has electric properties, and the second one does not.”
“But explain why Jyotsna di ruined the dish by adding too much water,” said Riya.
“There’s only one reason. The lovely aromatic ketones that were formed in the cooking pan got diluted in the excess water, making the dish too watery and tasteless. It’s very important to pay attention to the amount of water used while cooking. We Indians have a particular fondness for gravy. Gravy certainly can’t be made without water. But if you add too much water, it will overpower all the taste and aroma.
Now, future scientist, I have to go out. Tomorrow we’re going to Aminia for a meal. The rezala and paratha they make there are amazing!” Arka said, pushing back his chair and standing up.
Looking at her mobile screen, Riya excitedly said, “Tomorrow our class twelve results will be out, Arka da!”
Arka, without getting excited, said, “And I know that someone in our house is going to get great results! And that person will study science, that’s for sure. So, tomorrow we’re going to Aminia at Esplanade, right?”
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