I have a Question for you ?
I made Poori Potato for the family this morning for Brunch. Then this question popped up in my head. I used Plain Flour. Mixed a teaspoon of salt to a glass of water & add a bit of water and a bit of Oil and make it into a smooth dough after a lot of kneading. Make them into small balls and roll them flat with a rolling pin into thin Pooris and deep fry them in hot oil.
There are so many things we Deep fry and eat like Pakoras, Vadas, Samosas, Potato Chips etc etc.
Here is the question why and how does a poori dough rolled flat and inserted into hot oil split into two skins and puff up. Same thing happens with Pappadams from kerala. Tamil Nadu Appalams will not rise like the Pappadams. why ?.
When a Poori Bloats I know it is full of hot air like a hot air baloon it rises to the top of the Boiling oil. How does a Poori develop two skins. I am looking for a scientific explanation. Best answer will get a Uber Eats delivery of Poori Potato as a Thank you
Interesting so far no good answers and many have done Google searches and passed it on as their own and I caught them cheating as that is plagerism copying someone else's work. This is what is happening to students these days. No one wants to think logically or scientifically. Just do a Google search. Yes Google searches can help but they also make the brain dull and redundant too
Responses so far:
Ranga: poori and pappadam separate into 2 skins because they carry moisture, and are thick, large, thin dough doesn't separate into 2 surfaces. This ans. is from my wife and daughter. As to why it separates into 2 surfaces, requires may be quantum physics or particle physics, whichever is applicable.
Me: explain the difference between Appalams and Pappadams why one rises and the other does not despite both being bone dry and thin
Ranga: only appalam is dry, not pappadam which forms into 2 surfaces or ubbufies
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Amrita: Brother in laws answer: The moisture in the dough gets heated into steam which makes two layers as this gets trapped inside because the oil acts as barrier to let it escape Me: If this is true, why don't we get the same two layers in Bondas, Pakoras and Vadas ? Why do Pappadams puff up and Applams do not ?
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Ravi: I am from the defence ministry.. The question pertains to the Home ministry.. Will however pass it on
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Hema: First let me eat then explain ha ha ha
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Vickram: Best person nowadays to explain this is Krish Ashok. But, basically, the outer part of the dough gets sealed while the inside releases the trapped hot air.
Me: Why doesnt the vapour escape into the air. Vic:Sealed covers. Answers to further deep questioning needs approval of the Indian Supreme Court. 😂😂😂
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Varun: Interesting question. Even twice Nobel Laureate Madam Curie asked the same question when she came to India and was served puri sabzi. Me: Did she?. Thats news to me. Never even knew she came to India. Thanks
Varun: I read it as a school student.
Varun: The answer is that when puri is placed in hot oil, its lower surface becomes hotter than upper surface, with water within it becoming steam. As a result the lower surface puffs out with steam creating and filling gap vis-a-vis upper surface.
Me: How does it split into two layers is the question. Also not all pooris puff up. Why do some become biscuit like made from the same dough at the same time?
Me: Why does a vada not puff up?
Varun:The answer I gave was from Google.
Me: I knew you cheated
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Titu: It is because the boiling point of water in the poori is 100 degrees Celsius. The temperature of the oil in the pan is higher than this. When put poori in the oil, the water in the poori is converted to steam making the poori puff up and swell. Yum yum brunch.... poori with aloo!
Me: Why doesn't the water just escape as vapour ?
Titu: Because it cannot get out of the poori. Just make a small hole in the poori dough and the steam will escape and the poori will collapse. Most pooris don't stay puffed up for long. They flatten after a while
Me: You mean put a small hole in the poori dough before dropping it into hot oil. Then you will get something like a Do-Nut.
Titu: No. A small hole after the poori has puffed up in the hot oil. Think the hot temperature of the oil has something to do with the vapourisation of the water in the poori. Take it out of the oil and it will slowly flatten. So eat it hot when it is still puffed up.
Me: Some pooris made from the same dough do not rise and come out like crisp biscuits
Titu:Yes. That happens to us very often. Maybe the art of rolling out the dough plays a part. Also the amount of water and oil or ghee in the dough has to be in the right proportion. The oil's temperature could also contribute to this.
Me: Did you do a Google search?
Titu: Yes I did ...
Me: I knew you cheated
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Suresh: Just like a roti which swells open and is of similar thickness to the bottom the puri has thin upper layer because of the intensity of the heat. Steam in the middle follows archimedes principal and floats. If the oil is cold (not hot enough) it will stay submerged as the atta absorbs the oil.
Me: Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially, is equal to the weight
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Solly: Thanks for the tip about the difference between Kerala vs TN papadums. Good question about balooning
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Mohan: It is the moisture in the dough that is the root cause. The poori was not made from a dry flat piece of dough. There is a separation of layers because of the evaporation of the moisture trapped in the dough. Please remember that poori started off as a ball of dough. It is not a unitary mass and so it separates into layers when the heat evaporates the trapped moisture. It is made possible by the thinness of the poori. Similar thing happens when pulka roti is made. A thick roti does not have separate layers. Now, shall I send my address in this WhatsApp chat itself? I am waiting for Uber eats.
Me: What is inside a poori is not all water vapour and why does the water vapour nor escape into the atmosphere. Chappathis are rolled folded in four and rerolled forming four layers not poori.Poori is a ball rolled thin & flat once
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Indrajit Ray: I am no cook. Neither Tuktuk has excelled in it though she is brilliant in ideas..so I put the question to 3 ladies I could think of who indulge in cooking. None could give a specific reply.. My sister in law in Adelaide has a lot of interest. She hinted an answer which Tuktuk also mentioned. My mother a super cook used to say I remember it’s the very hot oil which expands the trapped air within the rolled flayed dough. And the layers are created and expands to accommodate that expanded air. So said my sister in law & Tuktuk. Incidentally, In 1952 my mother was part of a 3 women team of Indian cooking at London Gas Co organised International Kitchen Show where 52 countries took part for 2 days. Late Queen Mother Elizabeth's mother was the chief guest. She was thrilled seeing Ma making luchi which were ballooning up. A lot of people had similar thrills. The steam inside it cannot escape. Due to high temp the water in the poori turns into steam .This steam is powerful lifts the sheet of Gluten that is why pooris puff up .
Me: Why cant steam escape Boss?
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Kalpana: when hot oil falls on our skin it swells…. Same principle
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Raju: I think it’s the differential temperature and expansion between the top and bottom surfaces in the hot oil, since there is no stuffing in the poori. Me: Dai for Poori you mix the dough, make a small ball and roll it and rolled poori has no layers like in Chappathi where the rolled dough is folded into four making a quadrant and re rolled again creating 4 layers
Me: Dai this is the best answer I have received so far
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Monday 27th Sept:
So Many responses received yet no Scientific explanation so far.. This cartoon is the best response at this point of time Besides Pooris, Pani Poori and Channa Bhattura puff up even more that pooris.
Fine semolina, flour, and salt are the main ingredients to make this crispy puri for paani puri; whereas Bhatura is larger and made with Maida/all-purpose flour.
The Bhatura flour has to be fermented with yeast (or baking soda and baking powder) to make bhaturas and all of them puff up.
Pappadams and Applams are made from Urud Dhal (Black Gram) flour.
Appalam from Tamil Nadu don't puff up
There is the traditional Appalam, which is made from urad dal and stays flat when fried. It may expand in circumference but not in volume.
Kerala Pappadam that puffs up
The pappadom has a bit of soda and therefore puffs up like a bhatura when fried.
Many have said Hot oil is responsible for Poori Puffing up. If that is the case how do you explain this Air Fried Pani Puris that are almost spherical
Ranju: This reminds me of a joke regarding an American lady visiting her Indian friend in Mumbai. She was served this dish with hot pooris being brought from the kitchen by the servant every few minutes. She enjoyed this combination of poori and bhaaji. Then she made a request. Can I visit your kitchen and see how your cook pumps in hot air into your pooris??
Me: 😂😂😹😹😹
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Monju: Regarding the fluffing of the poori, there must be air trapped which causes the 2 surfaces to split open but held on at the edges by tight grip ( no air) . If there is anything placed within eg. Potatoes or vege as in samosas air will be captured by it. Try making samosas with very little filling or nothing to experiment.
Monju:Yes makes sense. If there are baking soda/powder or anything else which can react with water or yeast to produce air which causes the puffing. FYI dhal causes gas in your stomach - how I am not sure . But could be when it reacts with HCL secreted with your stomach. This is one problem I am facing - some dhal produce more gas than others.😂😂😂😂😂😂
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Muthu: Excellent question, but no answer from me! Sorry, buddy!
Me: I thought only you would have a scientific explanation for this question.
Muthu: Karpagam's theory is poori is made very thin. My speculative theory is that as soon as the poori is put into the hot oil the moisture in it evaporates and rises, which swells the outer batter skin which is still elastic due to shorter exposure to hot oil. We do not make poori, if we do I would do a thermal image (I have such a gizmo) and verify the theory. You can get a thermal imaging accessory for an iPhone, not terribly expensive.
Me: Muthu assuming the moisture in the poori evaporates, how much water is required to create a certain amount of steam Now if it is water causing the puffiness how do we explain the Pappad rising as it is as dry as a door nail yet applams do not rise. Is it water vapour or just hot air is what I am alluding to. The poori being fried thinks OMG this damn oil is too hot and sucks up air so it can float to the top. Also poori is just one layer how does it split into two layers. Most people are looking at Google for answer and saying it is water vapour. We can make poori dough just with oil and no water ?
Muthu:The dough (batter) is about 10% moisture (water). One poori after rolled out is about 15 grams, and that contains about 1.5 grams of moisture. If that evaporates fully, its volume is approximately 1.5x1250 milliliters, which is more than a liter. Water density is 1 gram/mL, water vapor density is approx 0.8 gram/liter
Me:This is the Muthu I know talking. Muthu it can't be all water vapour as the poori will become flat immediately on cooling down. It only goes down partially. It has to be Hot air too. I made puffed up pooris for lunch and packed left over ones in an airtight Plastic container around 5.00pm I ate one and it was still puffed up and no steam came out when I bit it either, Suggest you do some thermodynamic analysis on this and publish an article
Muthu:You are missing one thing. When it puffs up, the dough is still malleable and elastic. Once fried, it becomes rigid and water vapor/air from within will escape out due to diffusion. The fired upper thin layer is sufficiently rigid to maintain its shape. Dont expect anything to come off when it has been cold. From a freshly fried poori, if you poke in, you will see steam escaping. Try it next time with a fresh hot fried poori.
