Why do we fry with grease?

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sherifffruitfly

Senior Cook
Joined
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147
If water didn't boil away, would we use that instead?

Is there some other reason?

It just occurred to me while watching my pork chops sizzle. :)
 
It's the difference between boiling and frying. Drop pieces of potato into hot water and get mashed potatoes. Drop them into hot fat and get french fries.

Fat gets 150-200 F hotter than water. That higher heat is what makes fried foods brown.
 
It's the difference between boiling and frying. Drop pieces of potato into hot water and get mashed potatoes. Drop them into hot fat and get french fries.

Fat gets 150-200 F hotter than water. That higher heat is what makes fried foods brown.

Then could I pressure cook potatoes in water (achieving the oil-like temperature) and get a similar result?
 
When you drop a piece of potato in hot water do you get that "sizzle" that says it is getting crispy on the outside? No...

You can certainly pressure cook your potatoes in water and you will get cooked potatoes quicker - for mashing - not fried potatoes. You don't fry in water. Can you just accept that answer? You CAN'T fry in water :chef:
 
When you drop a piece of potato in hot water do you get that "sizzle" that says it is getting crispy on the outside? No...

You can certainly pressure cook your potatoes in water and you will get cooked potatoes quicker - for mashing - not fried potatoes. You don't fry in water. Can you just accept that answer? You CAN'T fry in water :chef:

Can I both accept it and ask why?
 
:LOL: Yes, you can accept it and ask why. But it would be better to accept it and try it both ways. And as my mother always said................BECAUSE! ;)

Another answer is - "it don't work" Water absorbs into the food - period - not gonna happen any other way. Oil causes a barrier to form on the outside keeping the oil out and leaving a crispy coating.
 
Oil goes to a much higher temperature for cooking so seals rather being absorbed - if you use fat/oil at a lower temperature, it can be absorbed and make your food very greasy,
 
You're getting into a very special area of cooking science called "Mailliard Reactions" or "Mailliard Browning Reactions". It's basically a chemical reaction between sugars (including carbohydrates which are sugars) and fats at high heat. Moisture (water) retards, limits or prevents those browning reactions.

Even if you could get water to 600ºF - you would not get browning ... the browning is a chemical reaction between the sugars in the food and the fats used in frying.

Humm .... example ... ever hear that when you want to sear some meat (like to make stew) you should not over crowd the pan? The reason is because if the meat is crowded too close together it steams and does not brown - thus the flavors generated during browning never develop.

Many people think that it is the fact that oil can be heated to a higher temperature than water without being under pressure that makes the difference - that just isn't so.
 
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Then could I pressure cook potatoes in water (achieving the oil-like temperature) and get a similar result?


A pressure cooker doesn't raise the temperature enough.

As Michael explained, You need the heat to generate the Maillard reaction. That won't happen with water.
 
Water, by its nature, is the ultimate solvent. It reacts, albeit slowly, with nearly every element there is. It is a part of , and is absorbed all foods, and breaks down the food tissues, be they meat or vegetable. It is the water in meat, mixed with enzymes that tenderize the meat tissue. Heat speeds the process.

Oils tend to be absorbed less, and don't break down as many substances as do meats. And the substances that are dissolved in oil are things like oil soluble vitamins and such.

Frying with oil cause two reactions. First, oil does not mix with water, especially when heated. Mix hot oil and water and it creates a violent reaction. The water becomes super-heated and litterally explodes. The same kind of reaction occurs when you pour water into acid. The sizzling you hear when frying foods is the result of that reaction. The hot oil contacts the moisture located in the outer layer of the food and superheats that moisture. The water can't boil away the heat energy and pops, or explodes, expanding vioplently, sometimes splashing hot oil all over the place. AS teh water vaporizes into steam, it is replaced by the oil, which is then free to heat the food sufficeintly to create the Mailliard Effect spoken of by Michael. The food browns, with the natural sugars and protiens changing both color and flavor.

Super-heated water can be obtained by heating the water in a very smooth container, in a microwave. Bubbles can't form and the water heats beyond the boiling point. If you add something to the water, or disturb it by, say, stirring it, the water boils suddenly and violently, sometimes splashing the scalding liquid all over the place.

If you took this super-heated water, and dropped an uncooked french fry cut potato into it, the potato would cook faster, but there would be not crisping, or browning, as the outer layer of water would never be replaced by the oil, and would reamain in the potato, as it would if the spud were boiled in water.

Also, hot air will not produce the same soft and crispy texture obtained by frying. You have probably eaten oven roasted potatoes before. Try this experiment. Take two potatoes and cut them into wedges. Sprinkle oil and seasonings on the first batch of potato wedges, and just seasoning on the other batch. Place them both on cookie sheets and bake in a 400 degree oven for 35 to 40 minutes. You will notice that the spuds that have had an oil coating brown better and have a more crispy, yet tender skin than the spuds without the oil. Hot air will brown the potatoes, but will toughen the outer layer, drying it out and not replacing the moisture with anything else.

Manufacturers have tried to duplicate the frying process with ultra-powerful microwave energy, theororizing that the high energy will flash-fry the potato chips, giving them a no-fat alternative to the fried chip. They found that the chips became tough and rubbery rather than light and crispy. They wer, however, able to overcome the problem by lightly spraying the chips with oil before nuking them. The oil was necessary to replace the lost moisture. The potatoes basorbed less oil than when fried, but still became light and crispy.

So you can see that oil serves multiple purposes in the frying process. It keeps the food from drying and becoming tough; it browns the food surface, and it adds flavor. It also makes some nutrients available to the body that would otherwise be lost.

Too much oil is bad for you. It is packed with calories and not much else. It may also contain cholesterol and contribute to coronary issues if abused. But when used properly, it is a valid and deliscious cooking substance that can't be duplicated by other means of cooking.

Oh, and if you are wondering why steaks and other meats cooked on the grill develop that same mailiard effect when they are not fried, remember that fat melts into oil and bastes the meat surface as it's cooking. Try grilling a very lean piece of meat or poultry, without covering it in any sauce and leaving it open to the direct heat and air. You will end up with a very dry and tough piece of food, with no nicely crisped surface. That's why the term "well-marbled" si synonomous with great grilling. You need the fat to obtain quality grilling results for direct cooking without added sauses, mops, or cooking in foil.

Seeeeeeya; Goodweed of the North
 
You're getting into a very special area of cooking science called "Mailliard Reactions" or "Mailliard Browning Reactions". It's basically a chemical reaction between sugars (including carbohydrates which are sugars) and fats at high heat. Moisture (water) retards, limits or prevents those browning reactions.

Even if you could get water to 600ºF - you would not get browning ... the browning is a chemical reaction between the sugars in the food and the fats used in frying.

Humm .... example ... ever hear that when you want to sear some meat (like to make stew) you should not over crowd the pan? The reason is because if the meat is crowded too close together it steams and does not brown - thus the flavors generated during browning never develop.

Many people think that it is the fact that oil can be heated to a higher temperature than water without being under pressure that makes the difference - that just isn't so.

Thanks for the beginnings of an answer I can research with!
 
Water, by its nature, is the ultimate solvent. It reacts, albeit slowly, with nearly every element there is. It is a part of , and is absorbed all foods, and breaks down the food tissues, be they meat or vegetable. It is the water in meat, mixed with enzymes that tenderize the meat tissue. Heat speeds the process.

Oils tend to be absorbed less, and don't break down as many substances as do meats. And the substances that are dissolved in oil are things like oil soluble vitamins and such.

Seeeeeeya; Goodweed of the North

Thanks!
 
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