View source for Deep frying

{{Short description|Cooking food under hot fat}}
{{Use dmy dates|date=September 2020}}
[[File:Frying range.JPG|thumb|right|alt=Two parcels of pastry being lowered in a basket into oil|A chef deep frying [[fish and chips]]]]

'''Deep frying''' (also referred to as '''deep fat frying''') is a [[cooking]] method in which food is submerged in hot [[fat]], traditionally [[lard]] but today most commonly [[Cooking oil|oil]], as opposed to the [[shallow frying]] used in conventional [[frying]] done in a [[frying pan]]. Normally, a [[deep fryer]] or [[chip pan]] is used for this; industrially, a [[pressure fryer]] or [[vacuum fryer]] may be used. Deep frying may also be performed using oil that is heated in a pot.<!--<ref name="Tsuji 2007"/> on PAGE 230, see the Tools section for other refs--> Deep frying is classified as a hot-fat cooking method.<ref name="Stanley Thornes 1996 p. 18"/><ref name="America 2007 p. 86"/> Typically, deep frying foods cook quickly since oil has a high rate of heat conduction and all sides of the food are cooked simultaneously.<ref name="Sumnu Sahin 2008 p. 6"/>

The term "deep frying" and many modern deep-fried foods were not invented until the 19th century, but the practice has been around for millennia. Early records and cookbooks suggest that the practice began in certain European countries before other countries adopted the practice.

Deep frying is popular worldwide, with deep-fried foods accounting for a large portion of global caloric consumption.

==History==
[[File:Peixinhos da horta.jpg|thumb|left|225px|alt=Pieces of bell pepper in a thin bubbly batter|''[[Peixinhos da horta]]'', the Portuguese ancestor of Japanese [[tempura]]]]

The English term ''deep-fried'' is attested from the early 20th century.<ref>{{cite web|title="deep", adj.|url=http://www.oed.com/view/Entry/48625|website=Oxford English Dictionary Online|publisher=Oxford University Press|access-date=24 May 2015|url-access=subscription }}</ref><ref>{{cite web|title="deep", v.|url=http://www.oed.com/view/Entry/48626|website=Oxford English Dictionary Online|publisher=Oxford University Press|access-date=24 May 2015|url-access=subscription }}</ref>

Deep-fried dough known as [[Zalabiyeh]] was eaten as early as the late 2nd millennium BC in [[Canaan]]. Frying food in [[olive oil]] is attested in [[Classical Greece]] from about the 5th century BC.<ref name=cooksinfo>{{cite web|title=Deep-Fried Foods|url=http://www.cooksinfo.com/deep-fried-foods|website=cooksinfo.com|publisher=Cooks Info|access-date=18 May 2015 | quote = The ancient Greeks began frying foods in olive oil sometime around or after the 5th century BC. Frying foods in oil was common in [[Rome]], certainly by the 1st century AD. Olive oil was mostly used, as it was plentiful. The Roman word was 'frigere.'}}</ref>{{unreliable source?|date=September 2017}}{{Better source needed|date=July 2020}} The 5th century AD Roman cookbook [[Apicius]] (De Re Coquinaria) offers a recipe for deep fried chicken in a cream sauce "''Pullus leucozomus''" fried in olive oil.<ref>{{Cite web |last=Curtius |first=Lacus |title=Apicius, De Re Coquinaria — Book VI |url=http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Apicius/6*.html#IX |access-date=2024-09-12 |website=penelope.uchicago.edu}}</ref> Sanskrit texts such as the 12th century [[Manasollasa]] (''Bhartur Upabhogakāraṇa)'' mention snacks like [[malpua]] and [[Vada (food)|vataka]] being submersed and fried in [[ghee]].<ref>{{Cite book |last1=Sen |first1=Colleen Taylor |url=https://books.google.com/books?id=AzysEAAAQBAJ&dq=Manasollasa+vataka&pg=PT495 |title=The Bloomsbury Handbook of Indian Cuisine |last2=Bhattacharyya |first2=Sourish |last3=Saberi |first3=Helen |date=2023-02-23 |publisher=Bloomsbury Publishing |isbn=978-1-350-12865-1 |language=en}}</ref> Deep-fried foods such as [[funnel cake]]s arrived in northern Europe by the 13th century,<ref>{{cite web|last1=Lapetina|first1=Adam|title=The true origins of 11 of your favorite fried foods|url=http://www.thrillist.com/eat/nation/where-fried-foods-came-from-corn-dogs-mozzarella-sticks-fried-candy-bars|website=thrillist.com|date=22 July 2014 |publisher=Trillist|access-date=18 May 2015}}</ref> and deep-fried fish recipes have been found in cookbooks in Spain and Portugal at around the same time<!-- "around the same time" means the 13th century"-->. [[Falafel]] arrived in the [[Middle East]] from [[Egypt]] as early as the 14th century.<ref>{{cite web|last1=Antunes|first1=Sonny|title=Falafel, a dish the entire Middle East can agree on|url=https://www.finedininglovers.com/stories/falafel-middle-east/|website=finedininglovers.com|publisher=Fine Dining Lovers|access-date=18 May 2015}}</ref><ref>{{cite news|last1=Guttman|first1=Vered|title=No matter where it originated, falafel is still Israel's national food|url=https://www.haaretz.com/blogs/modern-manna/no-matter-where-it-originated-falafel-is-still-israel-s-national-food-1.426265|access-date=18 May 2015|work=Haaretz|date=24 April 2012}}</ref><ref>{{cite web|last1=I. D.|first1=Morton|title=Geography and history of the frying process|url=http://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/viewFile/745/736|website=grasasyaceites.revistas.csic.es|access-date=18 May 2015}}</ref>

[[French fries]], invented in the early 17th century in Chile, became popular in the early 19th century western Europe.<ref>{{cite news|title=Who invented french fries? France and Belgium battle over who invented fried, crispy potato perfection|url=http://www.nydailynews.com/life-style/eats/france-belgium-invented-french-fries-article-1.1230918|access-date=18 May 2015|agency=AFP RELAXNEWS|work=Daily News|location=New York|date=1 January 2013}}</ref> In 1860, Joseph Malin combined [[Fish and chips|deep fried fish with chips]] (french fries) to open the first fish and chip shop in London.<ref name="ex">{{cite web|url=http://theex.com/main/food/milestones-in-deep-fried-history/the-history-of-fried-food|title=The History of Fried Food|website=theex.com|publisher=Canadian National Exhibition|access-date=18 May 2015}}</ref>

Modern deep frying in the United States began in the 19th century with the growing popularity of [[cast iron]], particularly around the [[Southern United States|American South]] which led to the development of many modern deep-fried dishes.<ref name=ex /> [[Doughnut]]s were invented in the mid-18th century,<ref>"'Old Salt' Doughnut hole inventor tells just how discovery was made and stomachs of earth saved." Special to ''The Washington Post''; ''The Washington Post'' (1877–1954), Washington, D.C.; 26 March 1916; p. ES9</ref> with foods such as [[onion ring]]s,<ref>{{cite web|title=Onion Ring|url=http://ifood.tv/onion/onion-ring/about|website=ifood.tv|access-date=18 May 2015}}</ref> [[deep fried turkey|deep-fried turkey]],<ref>{{cite web|last1=Moss|first1=Robert|title=How Cajun deep fried turkey took over America|url=http://www.seriouseats.com/2014/11/history-origins-southern-deep-fried-turkey-thanksgiving.html|website=seriouseats.com|publisher=Serious Eats|access-date=18 May 2015}}</ref> and [[corn dog]]s<ref>{{cite web |url= http://www.cbsnews.com/news/the-science-of-corn-dogs/ |first= Rome |last= Neal |date= 4 October 2002 |title= The science of corn dogs | work= [[CBS News]] |access-date=18 May 2015 |quote=Corn dogs are a food that we know from fall festivals, carnivals and tailgating. It actually got its start when German immigrants moved into Texas. Some of these new German immigrants were sausage-makers by trade, but had a hard time selling their wares in Texas. So, as a ploy, they took sausages, rolled them in a cornbread batter and fried them. The sticks came later.}}</ref> all being invented in the early 20th century. In recent years, the growth of [[fast food]] has expanded the reach of deep-fried foods,<ref name="Schreifer Sivell 1997 p. 11-PA2">{{cite book | last1=Schreifer | first1=K. | last2=Sivell | first2=J. | title=20 Questions-- Answered | publisher=Full Blast Productions | series=20 Questions-- Answered, Book One | year=1997 | isbn=978-1-895451-21-4 | url=https://books.google.com/books?id=VoBeAtTPDiYC&pg=SA11-PA2}}</ref> especially french fries.{{Citation needed|date=July 2021}}<ref>{{Cite web |last=Rogers |first=Maggi |date=17 August 2025 |title=Air Frying vs. Deep Frying |url=https://findnewdeals.com/air-frying-vs-deep-frying/ |access-date=17 August 2025 |website=Find New Deals}}</ref>

== Technique ==
[[File:Munkinpaisto.jpg|thumb|225px|alt=Rings of dough in oil, varying in colour from light to dark|[[Smultring]] being deep-fried]]

Deep frying food is defined as a process where food is submerged in hot oil at temperatures typically between {{convert|350|F|C }} and {{convert|375|F|C}}, but deep frying oil can reach temperatures of over 400&nbsp;°F (205&nbsp;°C).<ref>{{cite web |url=https://www.fsis.usda.gov/wps/wcm/connect/65f762d0-e4d0-4278-b5cb-2836854a3eda/Deep_Fat_Frying.pdf?MOD=AJPERES |archive-url=https://web.archive.org/web/20131129130646/http://www.fsis.usda.gov/wps/wcm/connect/65f762d0-e4d0-4278-b5cb-2836854a3eda/Deep_Fat_Frying.pdf?MOD=AJPERES |url-status=dead |archive-date=29 November 2013 |title=Deep Fat Frying and Food Safety |access-date=8 December 2020}}</ref>  One common method for preparing food for deep frying involves adding multiple layers of [[batter (cooking)|batter]] around the food, such as cornmeal, flour, or [[tempura]]; breadcrumbs may also be used.<ref name="SomeGoodDeepFriedNYTimesTAFI"/>

While most foods need batter coatings for protection, it is not as necessary for cooked noodles and potatoes because their high starch content enables them to hold more moisture and not shrink. Meats are sometimes cooked before deep frying to ensure that they are done inside while keeping juiciness.<ref name="SchinharlDickhaut2003">{{cite book|author1=Cornelia Schinharl|author2=Sebastian Dickhaut|author3=Kelsey Lane|title=Basic Asian: Everything You Need for Yin and Yang in the Kitchen|url=https://books.google.com/books?id=_OVuRq62iScC&pg=PT33|year=2003|publisher=Silverback Books|isbn=978-1-930603-65-3|page=26}}</ref>

When performed properly, deep frying does not make food excessively greasy, because the moisture in the food repels the oil. The hot oil heats the water within the food, [[steaming]] it; oil cannot go against the direction of this powerful flow because (due to its high temperature) the water vapor pushes the bubbles toward the surface.<ref name="Sumnu Sahin 2008 p. 6"/><ref>{{Cite book | first = Hervé | last = This | author-link = Hervé This | translator = Malcolm DeBevoise | title = Molecular Gastronomy | place = New York | publisher = Columbia University Press | year = 2006 | isbn = 978-0-231-13312-8 | page = [https://archive.org/details/moleculargastron0000this/page/63 63] | url = https://archive.org/details/moleculargastron0000this/page/63 }}</ref> As long as the oil is hot enough and the food is not immersed in the oil for too long, oil penetration will be confined to the outer surface. Foods deep-fried at proper temperatures typically absorb less than 2 tablespoons per {{cups|2.5|US}} of oil used.<ref name="Sweetser 2004 p. 6">{{cite book | last=Sweetser | first=W. | title=The Ultimate Fryer Cookbook | publisher=Running Press | series=Quintet Book | year=2004 | isbn=978-0-7624-1963-0 | url=https://books.google.com/books?id=yzKWy1f04C8C&pg=PA6 | access-date=18 May 2015 | page=6 }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> This oil absorption rate is around the same as occurs with shallow frying,<ref name="Sweetser 2004 p. 6"/> such as in a pan.

However, if the food is cooked in the oil for too long, much of the water will be lost and the oil will begin to penetrate the food. The correct frying temperature depends on the thickness and type of food, but in most cases it lies between {{convert|350|-|375|F|C}}.<ref name="SomeGoodDeepFriedNYTimesTAFI">{{cite news | url=https://www.nytimes.com/2013/10/23/dining/deep-fried-and-good-for-you.html | title=Deep Fried and Good for You | work=[[The New York Times]] | date=21 October 2013 | access-date=22 May 2015 | author=Bittman, Mark}}</ref><ref name="Pirie Clark Williams 2006 p. 229">{{cite book | last1=Pirie | first1=G. | last2=Clark | first2=J. | last3=Williams | first3=C. | title=Williams-Sonoma Bride & Groom Cookbook | publisher=Free Press | year=2006 | isbn=978-0-7432-7855-3 | url=https://archive.org/details/williamssonomabr0000piri | url-access=registration | access-date=18 May 2015 | page=[https://archive.org/details/williamssonomabr0000piri/page/229 229]}}</ref> An informal test for a temperature close to this range involves adding a tiny amount of flour into the oil and watching to see if it sizzles without immediately burning.<!--<ref name="SomeGoodDeepFriedNYTimesTAFI"/>--> A second test involves adding one piece of food to deep fry and watching it sink somewhat and rise back up.<!--<ref name="SomeGoodDeepFriedNYTimesTAFI"/>--> Sinking without resurfacing indicates that the oil is too cold; not sinking at all indicates that the oil is too hot.<ref name="SomeGoodDeepFriedNYTimesTAFI"/>

It is recommended that deep fryers be cleaned often to prevent contamination.<ref name=fryreviews>{{cite web|title=How To Clean A Deep Fryer&nbsp;– Deep Fat Fryer Cleaning|url=http://www.deepfryerreviewsdepot.com/how-to-clean-a-deep-fryer/|website=deepfryerreviewsdepot.com|publisher=Deep Fryer Reviews Depot|access-date=20 May 2015|archive-url=https://web.archive.org/web/20150510071447/http://www.deepfryerreviewsdepot.com/how-to-clean-a-deep-fryer/|archive-date=10 May 2015|url-status=dead}}</ref> The process of cooking with oil can also contaminate nearby surfaces as oil may splatter on adjacent areas. Oil vapors can also condense on more distant surfaces such as walls and ceilings. Supplies such as dish detergent and baking soda can effectively clean affected surfaces.<ref name=fryreviews />

==Tools==
{{Main|Deep fryer|chip pan}}

Deep frying is done with a [[deep fryer]], a pan such as a [[wok]] or [[chip pan]], a [[Dutch oven]], or a cast-iron pot. Additional tools include fry baskets, which are used to contain foods in a deep fryer and to strain foods when removed from the oil, and [[Meat thermometer|cooking thermometer]]s, used to gauge oil temperature. Tongs, [[slotted spoon]]s, [[wooden spoon]]s, and [[sieve]]s may be used to remove or separate foods from the hot oil.<ref name="Villas2013">{{cite book|author=James Villas|title=Southern Fried: More Than 150 Recipes for Crab Cakes, Fried Chicken, Hush Puppies, and More|url=https://books.google.com/books?id=QfT8AAAAQBAJ&pg=PA10|year=2013|publisher=Houghton Mifflin Harcourt|isbn=978-1-118-13076-6|pages=10–14}}</ref><!--The reference immediately before this comment covers everything but wooden spoon & sieve. The reference immediately after this comment covers sieve by mentioning it. Nothing covers wooden spoon. However, [[WP:BLUE]] for everything anyways.--><ref name="Atkin">{{cite book|author=Dee Atkin|title=Delicious Deep Fried Recipes: Classic & Exotic Fried Chicken Recipes, Fried Rice Recipes, Fried Tofu Recipes, Fried Zucchini Recipes and More|url=https://books.google.com/books?id=kLsnAwAAQBAJ&pg=PT16|page=16|id=GGKEY:2LNT2E533SU}}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Japanese deep frying tools include long metal chopsticks; the ''[[Agemono nabe|agemono-nabe]]'' deep frying pot, which is heavy for retaining heat and deep for holding oil; the ''[[Ami jakushi|ami-shakushi]]'' net ladle used for scooping out batter debris; and the ''[[Abura kiri|abura-kiri]]'' oil drying rack pan.<ref name="Tsuji 2007"/><!-- PAGE 103-->

<gallery mode="packed" class="center" caption="Deep frying tools">
File:Deep fryer.JPG|alt=A white plastic device shaped like a bucket, with controls on the front.|A deep fryer with [[slotted spoon]], for removing foods from the hot oil
File:Tongs2.JPG|alt=Two pieces of metal joined at one end by a hinge, with the other end flat and ridged.|[[Tongs]]
File:Handmade wooden spoons.jpg|alt=Wooden spoons and other utensils for frying.|Slotted and perforated [[wooden spoon]]s
File:Filters, അരിപ്പ.JPG|alt=Several wire meshes shaped like bowls, with metal handles.|Various [[strainer]]s, including a [[Spider (utensil)|spider]], left
File:EmpanadaFry.jpg|alt=A metal bowl with many small holes.|A strainer used in the preparation of [[empanada]]s
File:Ami shakushi.Scoop.jpg|alt=A wire mesh on a long handle.|An [[ami jakushi]] is a Japanese ladle or scoop that may be used to remove small drops of batter during the frying of [[tempura]].
</gallery>

==Dishes, foods, and culture==
{{main|List of deep fried foods}}
{{See also|List of fried dough foods|List of Thai dishes#Deep-fried dishes}}
{{More citations needed section|date=July 2021}}
Deep-fried foods are common in many countries, and have also been described as "a staple of almost all [[Street food|street cuisines]] on all continents".<ref name="Ashkenazi Jacob 2013 p. 90">{{cite book | last1=Ashkenazi | first1=M. | last2=Jacob | first2=J. | title=The Essence of Japanese Cuisine: An Essay on Food and Culture | publisher=Taylor & Francis | year=2013 | isbn=978-1-136-81549-2 | url=https://books.google.com/books?id=RSZTAQAAQBAJ&pg=PA90 | page=90}}</ref> There are hundreds of dishes that are associated with deep frying as most foods can be deep-fried. Examples of food that can be deep-fried include meat, poultry, fish and vegetables.<ref>{{cite web|url=http://www.cookeryonline.com/Topics/Deep%20Frying.html|title=Deep frying|publisher=Cookingonline.com}} Retrieved on 18 May 2015.</ref> [[Fish and chips]], for instance, combines deep-fried fish and deep-fried [[potatoes]]. French fries, [[doughnut]]s, [[onion ring]]s, and [[hushpuppies]] are common deep-fried foods.<ref name="Taylor 2013 p. 4">{{cite book | last=Taylor | first=J.M. | title=Deep-Fried Goodness | publisher=Workman Publishing Company | year=2013 | isbn=978-0-7611-7973-3 | url=https://books.google.com/books?id=HqGU799I8rQC&pg=PT4}}</ref> Other common deep-fried foods include Chinese ''you Bing'' deep-fried [[Chinese pancakes|pancakes]],<ref name="AngLiu1999">{{cite book|author1=Catharina Y.W. Ang|author2=Keshun Liu|author3=Yao-Wen Huang|title=Asian Foods: Science and Technology|url=https://books.google.com/books?id=C4cTXJYTE4QC&pg=PA94|date=5 April 1999|publisher=CRC Press|isbn=978-1-56676-736-1|page=94}}</ref> Southeast Asian ''[[jin deui]]'', and Japanese tempura. Less common deep-fried foods include [[maple leaves]],<ref name="Fantozzi 2014"/> [[peanut butter and jelly sandwich]]es,<ref name="Smith 2013 p. 351">{{cite book | last=Smith | first=A.F. | title=Food and Drink in American History: A "Full Course" Encyclopedia | publisher=ABC-CLIO | year=2013 | isbn=978-1-61069-233-5 | url=https://books.google.com/books?id=o7gxBgAAQBAJ&pg=PA351 | page=351}}</ref> [[Deep fried pizza|pizza]],<ref name="Guides 2012 p. 96">{{cite book | last=Guides | first=R. | title=Make the Most of Your Time in Britain | publisher=Rough Guides | year=2012 | isbn=978-1-4053-8861-0 | url=https://books.google.com/books?id=vlWK_C8In9gC&pg=PA96| page=96}}</ref> Mars and [[Snickers]] bars.<ref name="Kaercher Stefko 2006 p. 52">{{cite book | last1=Kaercher | first1=D. | last2=Stefko | first2=B. | title=Taste of the Midwest: 12 States, 101 Recipes, 150 Meals, 8,207 Miles and Millions of Memories | publisher=Globe Pequot Press | series=Best of the Midwest book series | year=2006 | isbn=978-0-7627-4072-7 | url=https://books.google.com/books?id=PCfA41FNXdEC&pg=PA52 | page=52 }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

In the United States, the ''Chicago Tribune'' notes that "you can deep fry almost anything".<ref name="Chicago Tribune Deep Fry Almost Anything 2015 TAFI">{{cite web | title=Photos: 75 deep fried foods | website=Chicago Tribune | date=21 January 2015 | url=http://www.chicagotribune.com/entertainment/dining/recipes/sns-viral-fried-pictures-photogallery.html | access-date=22 May 2015}}</ref> The American South has been noted as a modern center of innovation in the area of deep-fried food. According to the owner of a deep frying restaurant in the South, "If something is edible, you can bet that someone south of the [[Mason-Dixon line]] has tried to cook it in oil".<ref name=bluecollarculture />

<gallery mode="packed" caption="" widths="130px" heights="150px">
File:Friescookingbigrest.jpeg|alt=A row of five deep fryers, all steaming and filled with baskets of French fries.|[[French fries]] being cooked in a row of deep fryers
File:Deep frying chicken upper wing.JPG|alt=Battered chicken legs in bubbling oil.|Deep-frying chicken in a pan
File:DeepFriedTurkey.jpg|alt=A whole turkey, browned on the outside, on a metal stand.|A [[Turkey fryer|deep-fried turkey]]
File:Fried Swordfish collar.jpg|Deep-fried [[swordfish]] collar
File:Fried calamari.jpg|alt=Pale breaded rings on a plate.|Breaded, deep-fried [[calamari]]
File:Fried pork intestines.jpg|alt=Skewers with rings of pork intestine|Deep fried [[chitterlings]]
</gallery>

===Africa===
In Northern Africa, deep-fried dishes are a part of the cuisine.<ref name="Heine 2004 p. 92">{{cite book | last=Heine | first=P. | title=Food Culture in the Near East, Middle East, and North Africa | publisher=Greenwood Press | series=Food culture around the world | year=2004 | isbn=978-0-313-32956-2 | url=https://books.google.com/books?id=1jE5k5qeKbgC&pg=PA92 | page=92}}</ref> A common food in this region is the deep-fried [[fritter]], also referred to as "sponges".<ref name="Heine 2004 p. 92"/> In East Africa deep fried food is common, cooked in cast iron or earthenware pots.  Frying in batter is common. A Ugandan specialty is a kind of doughnut called Mandazi.  In areas of Southern Africa, street foods include deep-fried potato and cassava chips.<ref name="Murphy Armstrong Bainbridge Firestone 2010 p. 45">{{cite book | last1=Murphy | first1=A. | last2=Armstrong | first2=K. | last3=Bainbridge | first3=J. | last4=Firestone | first4=M.D. | title=Lonely Planet Southern Africa | publisher=Lonely Planet | series=Country Regional Guides | year=2010 | isbn=978-1-74059-545-2 | url=https://archive.org/details/isbn_9781740595452 | url-access=registration | page=[https://archive.org/details/isbn_9781740595452/page/45 45]}}</ref> Deep-fried foods in the country of South Africa include fish and chips, ''[[vetkoek]]'' and ''[[koeksister]]s'',<ref name="Albala 2011 p. 177">{{cite book | last=Albala | first=K. | title=Food Cultures of the World Encyclopedia: &#91;Four Volumes&#93; | publisher=ABC-CLIO | year=2011 | isbn=978-0-313-37627-6 | url=https://books.google.com/books?id=zG1H75z0EYYC&pg=PA177 | pages=177–178}}</ref> among others.

===Asia===
[[File:Insect food stall.JPG|thumb|225px|Deep-fried insects for human consumption sold at food stall in [[Bangkok]], [[Thailand]]|alt=Large baskets of insects and scorpions at a market.]]
Japanese [[tempura]] is a popular deep-fried food<ref name="Solomon 2006 p. 464">{{cite book | last=Solomon | first=C. | title=The Complete Asian Cookbook | publisher=Tuttle Publishing | year=2006 | isbn=978-0-8048-3757-6 | url=https://books.google.com/books?id=Mdfacqx2UaQC&pg=PA464| page=464}}</ref> that generally consists of battered and fried seafood and vegetables. Japanese deep-fried dishes, or [[List of Japanese dishes#Deep-fried dishes .28agemono.2C .E6.8F.9A.E3.81.92.E7.89.A9.29|Agemono]], include other styles besides tempura, such as [[Karaage]], [[Korokke]], [[Kushikatsu]], and [[Tonkatsu]].<!--There are no references for this sentence because there are just links-->

In areas of [[Southeast Asia]] such as Thailand, [[Insects as food|insects]] are commonly deep-fried for human consumption.<ref>Newman, Judith. [https://www.nytimes.com/1992/05/20/garden/what-is-fried-and-has-six-legs-welcome-to-insect-cuisine.html?pagewanted=1 ''What is fried and has six legs? Welcome to Insect Cuisine''.] ''The New York Times''. 20 May 1992. Retrieved 23 May 2015.</ref> Western-style fast food items such as donuts, deep-fried chicken, and deep-fried potatoes are also becoming popular in Asia.<ref>{{cite journal|last1=Seubsman|first1=Sam-ang|last2=Kelly|first2=Matthew|last3=Pataraporn|first3=Yuthapornpinit|last4=Sleigh|first4=Adrian|title=Cultural resistance to fast-food consumption? A study of youth in North Eastern Thailand|journal=International Journal of Consumer Studies| pmc=3086925 |pmid=21547247|doi=10.1111/j.1470-6431.2009.00795.x|volume=33|date=Nov 2009|issue=6|pages=669–675}}</ref>

In [[Indonesian cuisine|Indonesia]] deep fried food is quite common, serving as either a main dish or a snack. The ingredients are usually deep fried in [[palm oil]], the most widely used cooking oil in the country. Some popular deep fried foods include ''[[ayam goreng]]'' (chicken), ''[[pecel lele]]'' (catfish), ''[[pempek]]'' (fishcake) and [[tempeh]].<ref>{{Cite web |title=10 Most Popular Indonesian Deep-fried Dishes |url=https://www.tasteatlas.com/most-popular-deep-fried-dishes-in-indonesia |access-date=2022-04-20 |website=www.tasteatlas.com}}</ref> Fritters in Indonesia is generally identified as ''[[gorengan]]'', the most popular one including ''[[pisang goreng]]'' (banana fritter), ''[[Corn fritter|bakwan jagung]]'' (corn) and ''[[tahu goreng]]'' (tofu).

Deep-fried fish, [[tofu]], and ''{{lang|vi|[[chả giò]]}}'' are commonly eaten in [[Vietnamese cuisine]].<ref>{{cite book|title=Into the Vietnamese Kitchen: Treasured Foodways, Modern Flavors|first=Andrea|last=Nguyen|publisher=Potter/TenSpeed/Harmony|date=1 June 2011|page=513|isbn=978-1607741411|url=https://books.google.com/books?id=OdbTHVWsxlsC&pg=PT513}}</ref><ref>{{cite book|title=Vietnam, Cambodia, Laos & the Greater Mekong|first1=Nick|last1=Ray|first2=Tim|last2=Bewer|first3=Andrew|last3=Burke| first4=Thomas|last4=Huhti|first5=Siradeth |last5=Seng|year=2007|page=90|publisher=Lonely Planet |isbn=9781741047615|url=https://books.google.com/books?id=9i1zYNbcgwsC&pg=PA90}}</ref> Deep frying is also used to make several kinds of ''{{lang|vi|[[bánh]]}}'', including ''{{lang|vi|[[bánh rán]]}}'' (fried rice ball), ''{{lang|vi|[[bánh cam]]}}'' (sesame ball), ''{{lang|vi|[[bánh tiêu]]}}'' (hollow doughnut), ''{{lang|vi|[[bánh rế]]}}'' (sweet potato pancake), ''{{lang|vi|[[bánh chuối]] chiên}}'' (banana fritter), [[West Lake (Hanoi)|Hồ Tây]]–style ''{{lang|vi|[[bánh tôm]]}}'' (shrimp fritter), and ''{{lang|vi|[[bánh gối]]}}'' (pillow cake).

Deep-fried sticks of dough, known as [[youtiao]] in Chinese, are eaten in many East and Southeast Asian cuisines.

In Hong Kong, [[cmn:豬大腸|deep-fried intestine of pigs]] is a popular food.<ref>{{Cite web|title=Hong Kong's best street food essentials|url=https://www.timeout.com/hong-kong/restaurants/hong-kong-street-food-essentials|access-date=2021-05-06|website=Time Out Hong Kong|language=en}}</ref>

In [[South Asia]], popular deep fried snacks are [[samosa]], [[jalebi]], and [[pakora]].

===Europe===
Many countries such as the [[United Kingdom]] use pure or [[Hydrogenation|hydrogenated]] [[rapeseed oil]] for deep-frying.<ref name="Rossell 2001 p. 31">{{cite book |last=Rossell |first=J.B. |url=https://books.google.com/books?id=TiUZIJ0LQmkC&pg=PA31 |title=Frying: Improving Quality |publisher=CRC Press |year=2001 |isbn=978-1-85573-556-9 |series=Woodhead Publishing Series in Food Science, Technology and Nutrition |page=31}}</ref>  [[Fish and chips]] is a very popular deep-fried dish in the U.K. since it originated in London in the 19th century and became popular among the working class. Its popularity continues with 229 million portions of fish and chips being sold annually in England alone.<ref name="bbcfish">{{cite news |last1=Zaino |first1=Caitlin |date=19 April 2013 |title=Chipping away at the history of fish and chips |publisher=BBC |url=http://www.bbc.com/travel/story/20130409-chipping-away-at-the-history-of-fish-and-chips |access-date=24 May 2015}}</ref>

There is an annual trade fair devoted to deep-fried foods called the International Symposium on Deep-Fat Frying which features discussions on deep fat frying as well as exhibitions by companies involved with the process.<ref>{{cite web|title=8th International Symposium on Deep Frying Better understanding, better fried products 15–17 September 2015, Munich, Germany |url=http://www.eurofedlipid.org/meetings/munich2015/ |website=eurofedlipid.org |publisher=Euro Fed Lipid |access-date=12 June 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150615183405/http://www.eurofedlipid.org/meetings/munich2015/ |archive-date=15 June 2015}}</ref>

Belgian tradition requires [[French fries]] to be deep-fried in filtered fat of [[cattle]], locally called ''blanc de boeuf'' or ''ossewit''.

The Mediterranean diets traditionally use olive oil for deep-frying, which it is absorbed by the food in the process. Research indicates that [[virgin olive oil]] is unique among other cooking oils because it is very rich in monounsaturated fatty acids and contains beneficial micronutrients.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S0023643806001927 | doi=10.1016/j.lwt.2006.07.003 | title=Retention and distribution of natural antioxidants (α-tocopherol, polyphenols and terpenic acids) after shallow frying of vegetables in virgin olive oil | year=2007 | last1=Kalogeropoulos | first1=Nick | last2=Mylona | first2=Anastasia | last3=Chiou | first3=Antonia | last4=Ioannou | first4=Maria S. | last5=Andrikopoulos | first5=Nikolaos K. | journal=LWT - Food Science and Technology | volume=40 | issue=6 | pages=1008–1017 | url-access=subscription }}</ref>

The [[deep-fried Mars bar]] originated in Scotland,<ref name="NHS Choices 2014">{{cite web |date=10 July 2014 |title=Deep-fried Mars bars: no link with sudden stroke&nbsp;– Health News |url=http://www.nhs.uk/news/2014/09September/Pages/Deep-fried-Mars-bars-unhealthy-but-no-killer.aspx |url-status=dead |archive-url=https://web.archive.org/web/20150524175205/http://www.nhs.uk/news/2014/09September/Pages/Deep-fried-Mars-bars-unhealthy-but-no-killer.aspx |archive-date=24 May 2015 |access-date=24 May 2015 |website=NHS Choices}}</ref> with The Carron Fish Bar in Stonehaven claiming to have invented it in the early 1990s.<ref name="BBC News 2012">{{cite news |date=5 September 2012 |title=Deep-fried Mars bars disowned by chocolate firm |work=BBC News |url=https://www.bbc.com/news/uk-scotland-north-east-orkney-shetland-19487149 |access-date=24 May 2015}}</ref>

===North America===
In the United States, [[soybean oil]] is often used for deep-frying.<ref name="Rossell 2001 p. 31"/> [[Beignet]]s, originally a French dish, are a popular deep-fried pastry in the U.S. city of [[New Orleans]]. Deep-fried food has been a core part of the culture of the American South with many restaurants solely serving deep-fried foods. The owner of one such restaurant has said of deep-fried food that "in the South it's a way of life".<ref name=bluecollarculture /> Fast food is one of the most common ways to consume deep-fried food in North America.

Novelty deep-fried foods are popular today in American [[fairs]], especially those in the American South.<ref name=bluecollarculture>{{cite book|last1=Booker|first1=M. Keith|title=Blue-Collar Pop Culture: From NASCAR to Jersey Shore|date=9 March 2012|publisher=Praeger|isbn=978-0313391989|page=253|edition=Volume 1|url=https://books.google.com/books?id=D2BwllvrlxsC&pg=RA1-PA253|access-date=24 May 2015}}</ref> Hundreds of items are served at these fairs. Some of them include deep-fried beer, butter, and bubblegum. Additionally, deep frying can be used as a form of artwork by frying non-edible objects, such as [[electronics]].<ref name="Smith 2012">{{cite web | last=Smith | first=Kevin | title=What Happens When You Deep Fry An iPad? | website=Business Insider | date=4 June 2012 | url=http://www.businessinsider.com/deep-fried-gadgets-2012-6 | access-date=20 May 2015}}</ref> Artists such as Henry Hargreaves have deep-fried replicas of electronic items such as [[iPad]]s, [[Game Boy]]s, and [[laptops]].<ref>{{cite news|title=Deep-Fried Gadgets: Artist Henry Hargreaves Deep-Fries (Fake) iPad, iPhone And More|url=http://www.huffingtonpost.com/2012/06/06/deep-fried-gadgets-henry-hargreaves_n_1568935.html|access-date=24 May 2015|work=The Huffington Post|date=4 June 2012}}</ref>

Deep-fried food contests are frequently held at fairs such as the [[Texas State Fair]], where they hold an annual contest for the most creative deep-fried food.<ref name=mentalfloss>{{cite web|last1=Gamble|first1=Cole|title=25 Deep-Fried Foods From the Texas State Fair|url=http://mentalfloss.com/article/31488/25-deep-fried-foods-texas-state-fair|website=mentalfloss.com|date=5 September 2012|publisher=Mental Floss|access-date=20 May 2015}}</ref> Notable past winners have included [[fried Coke]] and [[deep-fried butter]], both invented by [[Abel Gonzales]].<ref>{{cite news|title=Come fry with me|url=https://www.economist.com/united-states/2009/10/08/come-fry-with-me|access-date=20 May 2015|newspaper=The Economist|date=8 October 2009}}</ref> Since 2013, an American reality competition show called ''deep-fried Masters'', produced by [[Discovery Networks]], holds deep frying competitions at several state fairs across the country.<ref>{{cite news|title=Deep Fried Masters |url=http://press.discovery.com/us/da/programs/deep-fried-masters/ |access-date=23 May 2015 |publisher=Discovery Networks |date=12 July 2013 |url-status=dead |archive-url=https://web.archive.org/web/20150614035311/http://press.discovery.com/us/da/programs/deep-fried-masters/ |archive-date=14 June 2015}}</ref>

===Oceania===
[[Fish and chip shop|Fish and chip]] shops in Australia may purvey several types of deep-fried foods, along with other food types.<ref name="Lang 2010 p. 521">{{cite book | last=Lang | first=L.B. | title=Australia | publisher=Dorling Kindersley | series=Eyewitness travel guides | year=2010 | isbn=978-0-7566-6082-6 | url=https://books.google.com/books?id=DGb1I4Br8EYC&pg=PA521 | access-date=23 May 2015 | page=521}}</ref>

===South America===
[[File:Buñuelos.JPG|thumb|225px|[[Buñuelo]]s|alt=Fried balls of dough in a basket.]]
The [[buñuelo]], a fried dough ball popular in Central America and Greece, is a popular deep-fried [[Snack food|snack]] and street food in South America.<ref name="Ashkenazi Jacob 2013 p. 90"/> [[Picarones|Picarone]], a Peruvian dessert originated in the colonial period, are deep-fried doughs made with pumpkin and sweet potatoes, popular in Peru and Chile, especially during harvest festivals.,<ref name="Castella2012"/> a family of deep fried cakes is well known across, [[sopaipillas]] a Chilean bread are deep fried  in oil or butter also made with pumpkin, Chancay a Peruvian bread made of flour, salt and [[yeast]], known as [[chipá]] cuerito in Paraguay and [[Torta frita]] in [[Argentina]] and [[Uruguay]], made of flour, salt and yeast, sometimes addition with milk and [[cow fat|animal fat]] and fried in  cow fat, the [[churro]], a fried dough popular in [[Spain]] is a popular fried snack and street food in Argentina and Uruguay, [[milanesa]] a deep fried breaded [[veal]] [[beef]] from Argentina, Paraguay and Uruguay.

== Oil deterioration and chemical changes ==
{{See also|Deep fryer#Oil filtration}}
{{More citations needed|section|date=August 2021}} 
Deep fat frying involves heating oil to temperatures in excess of 180&nbsp;°C in the presence of moisture and air. These conditions can induce a series of complex chemical reactions which may impact the quality of both the food and the oil it is cooked in. Examples of different chemical reactions include the production of [[Radical (chemistry)|free radicals]], [[Redox|oxidation]], [[hydrolysis]], [[isomerization]] and [[polymerization]]. The exact reactions are dependent upon factors such as the oil type, frying conditions, and food being cooked. When frying, water can attack the ester linkage of triacylglycerols, resulting in mono- and diglycerols, glycerol, and free fatty acids (a type of [[hydrolysis]] reaction). The aforementioned hydrolysis reaction is enhanced by the produced [[fatty acid]]s and other low molecular weight acid compounds.<ref>{{Cite journal|last1=Mariod|first1=Abdalbasit|last2=Omer|first2=Nuha|last3=Al|first3=El Mugdad|first4=Mohammed|last4=Mokhtar |date=2014-09-09|title=Chemical Reactions Taken Place During deep-fat Frying and Their Products: A review|url=https://www.researchgate.net/publication/270727167|journal=Sudan University of Science & Technology SUST Journal of Natural and Medical Sciences|volume=Supplementary issue|pages=1–17}}</ref>

Overheating or over-using the frying oil leads to formation of [[Rancidification|rancid-tasting]] products of [[redox|oxidation]], [[polymerization]], and other deleterious, unintended or even toxic compounds<ref>{{cite book | title=Household use of solid fuels and high-temperature frying | publisher=Lyon, France : International Agency for Research on Cancer; Distributed by WHO Press, 2010. | author=IARC Working Group on the Evaluation of Carcinogenic Risks to Humans | year=2010 | location=Lyon, France; Geneva}}</ref> such as [[acrylamide]] (from [[starch]]y foods).  Recent research suggests fat deterioration may be worse when fat or oil is fried with food than when fat or oil is tested on its own in a laboratory.<ref>[[BBC]] (London) undated [https://www.bbc.co.uk/programmes/articles/3t902pqt3C7nGN99hVRFc1y/which-oils-are-best-to-cook-with Which oils are best to cook with?]</ref> [[Vacuum fryer|Deep-frying under vacuum]] helps to significantly reduce acrylamide formation,<ref>Granda, C.; Moreira, R.G.; Tichy, S.E. (2004). "Reduction of Acrylamide Formation in Potato Chips by Low-temperature Vacuum Frying Journal of Food Science". 69 (8). Pages 405–411.</ref> but this process is not widely used in the [[food industry]] due to the high investment cost involved.

Some useful tests and indicators of excessive oil deterioration are the following:
* Sensory&nbsp;– darkening, smoke, foaming, thickening, rancid taste and unpleasant smell when heating. This is the most unreliable way to decide when to change oil because those are very individual factors and can depend on different causes.
* Testing strips&nbsp;– decide when to change oil depending on FFA ([[free fatty acid]]s) only<ref name="Peng Morin 1991 p. 86">{{cite book | last1=Peng | first1=S.K. | last2=Morin | first2=R.J. | title=Biological Effects of Cholesterol Oxides | publisher=Taylor & Francis | year=1991 | isbn=978-0-8493-6776-2 | url=https://books.google.com/books?id=lzrCYjxe_swC&pg=PA86 | page=86}}</ref>
* Oil-tester&nbsp;– measurement tool to exactly define the point of change oil by TPM/TPC (Total polar material/compounds)
* Laboratory&nbsp;– [[acidity]], [[anisidine value]], [[viscosity]], total [[chemical polarity|polar]] [[chemical compound|compounds]], polymeric [[triglycerides]].

Instruments that indicate total polar compounds, currently the best single gauge of how deep-fried an object is, are available with sufficient accuracy for restaurant and industry use.

==Hazards==
[[File:Chip-pan-fire.jpg|thumb|left|200px|When deep frying, fires can be very severe, with chip pan fires being the leading cause of house fires in the United Kingdom.<ref>{{cite web|title=Chip pans|url=http://www.cambsfire.gov.uk/firesafety/94.php|website=cambsfire.gov.uk|publisher=Cambridgeshire Fire and Rescue Service|access-date=20 May 2015|url-status=dead|archive-url=https://web.archive.org/web/20150520082554/http://www.cambsfire.gov.uk/firesafety/94.php|archive-date=20 May 2015}}</ref>|alt=A pillar of fire erupts from a pan and spreads across the ceiling above.]]
Cooking oil is not [[flammable]] at room temperature but can become flammable when used at high temperatures.<ref name="Trudie du Toit 2007 p. 95"/> Fires ensue if it gets ignited under these conditions.<ref name="Ferrier Shuttleworth 1982 p. 60"/><ref name="Botha2007">{{cite book|author=Trudie du Toit, Linda Botha|title=FCS Food Preparation L2|url=https://books.google.com/books?id=rdlDftbyBpIC&pg=PA96|year=2007|publisher=Pearson South Africa|isbn=978-1-86891-824-9|page=96}}</ref> Further, attempts to extinguish an oil fire with water can cause an extremely dangerous condition (a [[Boilover#Slopover|slopover]])<ref name="Simpson 2010 p. 11"/> as they cause the water to flash into steam due to the high heat of the oil, in turn sending the burning oil in all directions and thus aggravating the fire. This is the leading cause of house fires in the United Kingdom. Instead, oil fires must be extinguished with a class F [[fire extinguisher]] or by starving the fire of oxygen, such as can be accomplished by putting a lid back on the pan or using a [[fire blanket]]. Other means of extinguishing an oil fire include application of dry powder (e.g., [[baking soda]], salt)<ref name="Peterson2012">{{cite book|author=James Peterson|title=Glorious French Food: A Fresh Approach to the Classics|url=https://books.google.com/books?id=lubHmYXyfLYC&pg=PT577|date=29 February 2012|publisher=Houghton Mifflin Harcourt|isbn=978-0-544-18655-2|page=550}}</ref> or [[fire fighting foam|firefighting foam]]. Most commercial deep fryers are equipped with automatic [[fire suppression system]]s using foam.{{Citation needed|date=July 2021}}

Spilled hot cooking oil can also cause severe [[third degree burn]]s,<ref name="Beasley 2003 p. 75"/><ref>{{cite web|last1=Anderson|first1=L. V.|title=The Technique That Will Make You Want to Batter and Fry Everything|url=http://www.slate.com/blogs/browbeat/2015/04/01/best_batter_for_frying_simple_recipe_to_deep_fry_everything_video.html|website=slate.com|date=April 2015|access-date=31 July 2015}}</ref> In the worst-case scenario, severe burns can be fatal. The higher temperatures<ref name="Beasley 2003 p. 75"/> and tendency of oil to stick to the skin make spilled hot cooking oil far more dangerous than spilled hot water. Children can accidentally place their hands on top of the stove, play with the materials while being cooked, or accidentally pull the pot down, which can cause significant injury.<ref name="Chiarello Wisner Petzke 2008 p. 139">{{cite book | last1=Chiarello | first1=M. | last2=Wisner | first2=P. | last3=Petzke | first3=K. | title=The Tra Vigne Cookbook: Seasons in the California Wine Country | publisher=Chronicle Books | year=2008 | isbn=978-0-8118-6379-7 | url=https://books.google.com/books?id=AY4mvdrTaKEC&pg=PA139 | page=139}}</ref> If children are present, the utmost care should be used when deep frying so that their safety can be protected at all times.<ref name="Chiarello Wisner Petzke 2008 p. 139"/><ref name="Singh 2012 p. 13">{{cite book | last=Singh | first=P. | title=The Everything Indian Slow Cooker Cookbook: Includes Pineapple Raita, Tandoori Chicken Wings, Mulligatawny Soup, Lamb Vindaloo, Five-Spice Strawberry Chutney...and Hundreds More! | publisher=Adams Media | series=Everything (Cooking) | year=2012 | isbn=978-1-4405-4168-1 | url=https://books.google.com/books?id=ZcPtQLaCbF0C&pg=PA13 | page=13 }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

==Environmental==
[[File:SpentcookingoilbinAustinTX.JPG|thumb|right|225px|A bin for spent cooking oil in [[Austin, Texas]], managed by a recycling company|alt=A large bin, with "GREASE ONLY" stamped on the lid.]]
Deep frying produces large amounts of [[Brown grease|waste oil]], which must be disposed of properly. Waste oil can contribute to the creation of [[fatberg]]s, overflow sewage systems, bind to the walls of sewage pipes, and interfere with sewage treatment.<ref>{{cite web|last1=Carman|first1=Tara|title=Grease, wet wipes clog Metro Vancouver's sewers|url=https://vancouversun.com/Grease+wipes+clog+Metro+Vancouver+sewers/11072929/story.html|website=The Vancouver Sun|access-date=30 May 2015|date=21 May 2015|archive-date=8 November 2020|archive-url=https://web.archive.org/web/20201108140242/http://www.vancouversun.com/Grease+wipes+clog+Metro+Vancouver+sewers/11072929/story.html|url-status=dead}}</ref> Waste oil from deep frying is increasingly being recycled and refined into [[biodiesel]].<ref name="Johanson 2010 p. 18"/>

The heating element in a deep fryer consumes enormous energy, electricity or otherwise. According to one source, an average home appliance deep fryer draws 2,000 watts.<ref name="CliftCuthbert2007">{{cite book|author1=Jon Clift|author2=Amanda Cuthbert|title=Energy, Use Less—save More: 100 Energy-saving Tips for the Home|url=https://archive.org/details/energyuselesssav00clif|url-access=registration|year=2007|publisher=Chelsea Green Publishing Company|isbn=978-1-933392-72-1|page=[https://archive.org/details/energyuselesssav00clif/page/13 13]}}</ref> Potatoes that are stored in artificially humidified warehouses contain more water, which makes the time required to deep fry them into chips longer. This increases the [[Carbon footprint|carbon dioxide footprint]] of commercially producing chips because more energy is required for frying over a longer time.<ref name="Humid Chips TAFI">{{cite news | url=https://www.nytimes.com/2007/12/14/opinion/14murray.html | title=The Deep-Fried Truth | work=[[The New York Times]] | date=14 December 2007 | access-date=22 May 2015 | author=Murray, Sarah}}</ref>

==Health==
{{more medical citations needed|section|date=October 2022}}
The process of deep frying food is generally detrimental to its nutritional value. The oils that foods absorb in their batter typically contain large amounts of [[saturated fat]]s and [[trans fat]]s. Consumption of large amounts of saturated and trans fats has been linked to a higher risk for some [[cancer]]s.<ref name=prostate>{{cite web|title=Study finds eating deep-fried food is associated with an increased risk of prostate cancer|url=https://www.fredhutch.org/en/news/releases/2013/01/eating-deep-fried-foods-associated-with-risk-of-prostate-cancer.html|website=fredhutch.org|date=28 January 2013|access-date=19 May 2015}}</ref>

Eating deep-fried foods has also been linked to higher [[cholesterol]] levels, [[obesity]], [[heart attacks]], and [[diabetes]].<ref name=timehealth>{{cite magazine|last1=Davis|first1=Robert|title=Health Risks of Fried Foods May Be Overblown|url=https://healthland.time.com/2013/09/24/dont-be-so-quick-to-shun-the-french-fry/|access-date=19 May 2015|magazine=Time}}</ref> Deep-fried foods cooked at certain temperatures can also contain [[acrylamide]]. This discovery in 2002 led to international health concerns. Subsequent research has however found that it is not likely that the [[Acrylamide|acrylamides]] in burnt or well-cooked food cause cancer in humans; [[Cancer Research UK]] categorizes the idea that burnt food causes cancer as a "myth".<ref name=cruk>{{cite web |url=https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/cancer-myths/can-eating-burnt-foods-cause-cancer |publisher=Cancer Research UK |title=Can eating burnt foods cause cancer? |date=15 October 2021 }}</ref>

Additionally, fat degradation processes ([[lipid peroxidation]]) during deep frying results in the loss of nutritional value in deep-fried foods.<ref>{{cite journal|last1=Orozco-Solano|first1=M. I.|last2=Priego-Capote|first2=F.|last3=Luque de Castro|first3=M. D.|title=Analysis of esterified and nonesterified fatty acids in serum from obese individuals after intake of breakfasts prepared with oils heated at frying temperature|journal=Analytical and Bioanalytical Chemistry|date=10 May 2013|volume=405|issue=18|pages=6117–6129|doi=10.1007/s00216-013-7004-0|pmid=23657457|publisher=Springer|s2cid=883176|issn=1618-2650}}</ref>

Cooking oil that has been used for too long may in addition cause blood pressure elevation<ref>{{Citation |last1=Jaarin |first1=Kamsiah |title=Chapter 10 - Heated Oil and Its Effect on Health |date=2018-01-01 |work=Food Quality: Balancing Health and Disease |pages=315–337 |editor-last=Holban |editor-first=Alina Maria |url=https://www.sciencedirect.com/science/article/abs/pii/B9780128114421000109#:~:text=The%20use%20of%20repeatedly%20heated%20oil%20may%20cause%20hypertension,%20promote,and%20kidney%20structure%20and%20function. |access-date=2025-01-18 |series=Handbook of Food Bioengineering |publisher=Academic Press |isbn=978-0-12-811442-1 |last2=Masbah |first2=Norliana |last3=Kamisah |first3=Yusof |editor2-last=Grumezescu |editor2-first=Alexandru Mihai}}</ref> and vascular hypertrophy.<ref>{{cite journal |title=Chun-Yi Ng, Yusof Kamisah, Othman Faizah, & Kamsiah Jaarin, 2013 Recycled Deep-frying Oil Causes Blood Pressure Elevation and Vascular Hypertrophy in Sprague-Dawley Rats 1(1) : 2-6 |url=http://spaj.ukm.my/fper/index.php/rumes/article/download/22/14 |url-status=dead |archive-url=https://web.archive.org/web/20161009181256/http://spaj.ukm.my/fper/index.php/rumes/article/download/22/14 |archive-date=9 October 2016}}</ref>

[[Trans fat|Trans fats]] are used in shortenings for deep-frying in restaurants, as they can be used for longer than most conventional oils before becoming rancid. In the early 21st century, non-hydrogenated vegetable oils that have lifespans exceeding that of the frying shortenings became available.<ref>{{cite web|last=NYC Board of Health |title=Board of Health Approves Regulation to Phase Out Artificial Trans Fat: FAQ |url=http://www.nyc.gov/html/doh/html/cardio/cardio-transfat-healthcode-faq.shtml#7 |access-date=7 January 2007 |url-status=dead |archive-url=https://web.archive.org/web/20061006022908/http://www.nyc.gov/html/doh/html/cardio/cardio-transfat-healthcode-faq.shtml |archive-date=6 October 2006}}</ref> As fast-food chains routinely use different fats in different locations, trans fat levels in fast food can have large variations.<ref>{{cite news|title=What's in that french fry? Fat varies by city|work=[[NBC News]]|date=12 April 2006|url=http://www.nbcnews.com/id/12287818|archive-url=https://web.archive.org/web/20151017191934/http://www.nbcnews.com/id/12287818/|url-status=dead|archive-date=17 October 2015|access-date=7 January 2007}} AP story concerning {{cite journal | pmid = 16611965 | doi=10.1056/NEJMc052959 | volume=354 | title=High levels of industrially produced trans fat in popular fast foods | date=April 2006 | journal=N. Engl. J. Med. | pages=1650–2 | last1 = Stender | first1 = S | last2 = Dyerberg | first2 = J | last3 = Astrup | first3 = A| issue=15 | doi-access=free }}</ref> The amount of trans fat that is formed during frying appears to increase with frying temperature, frying time, oil oxidation, and oil reuse.<ref>{{cite journal |last1=Bhardwaj |first1=Swati |last2=Passi |first2=Santosh Jain |last3=Misra |first3=Anoop |last4=Pant |first4=Kamal K. |last5=Anwar |first5=Khalid |last6=Pandey |first6=R. M. |last7=Kardam |first7=Vikas |title=Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation |journal=Food Chemistry |date=1 December 2016 |volume=212 |pages=663–670 |doi=10.1016/j.foodchem.2016.06.021 |pmid=27374582 |url=https://www.sciencedirect.com/science/article/abs/pii/S0308814616309141 |access-date=2 March 2021|url-access=subscription }}</ref>

Some studies have found that deep frying in olive and sunflower oils has been found to be less of a detriment to health and in some cases have positive effects on [[insulin]] levels.<ref name=timehealth /> Oil can be reused a few times after original use after straining out solids.<ref name="SomeGoodDeepFriedNYTimesTAFI"/> However, excessive use of the same oil can cause it to break down and release compounds into the food that may be carcinogenic, affect liver health, or influence the body's ability to absorb vitamins.<!--<ref name="Ogilvie 2014">--> Some European countries have set public health standards for the safety of frying oil.<ref name="Ogilvie 2014">{{cite web | last=Ogilvie | first=Megan | title=Deep fried food may be worse for you than you think | website=The Toronto Star | date=10 October 2014 | url=https://www.thestar.com/life/2014/10/10/deep_fried_food_may_be_worse_for_you_than_you_think.html | access-date=23 May 2015}}</ref>

== See also ==
{{Portal|Cooking|Food}}

* [[Lipid peroxidation]]
* [[List of deep fried foods]]
* [[Recovery time (culinary)]]
* [[Internet memes#Modern_memes|Deep frying (internet phenomenon)]]

==References==
{{Reflist|refs=
<ref name="America 2007 p. 86">{{cite book | last=America | first=Culinary Institute of | title=Techniques of Healthy Cooking, Professional Edition | publisher=Wiley | year=2007 | isbn=978-0-470-05232-7 | url=https://books.google.com/books?id=KDa4ZB_gvWgC&pg=PA86| page=86}}</ref>
<ref name="Stanley Thornes 1996 p. 18">{{cite book | title=Food Preparation and Cooking: Cookery units. Student guide | publisher=Stanley Thornes | series=Catering and hospitality, NVQ/SVQ2 | year=1996 | isbn=978-0-7487-2566-3 | url=https://books.google.com/books?id=vRcidxIUWYMC&pg=PA18 | page=18}}</ref>
<ref name="Sumnu Sahin 2008 p. 6">{{cite book | last1=Sumnu | first1=S.G. | last2=Sahin | first2=S. | title=Advances in Deep-Fat Frying of Foods | publisher=CRC Press | series=Contemporary Food Engineering | year=2008 | isbn=978-1-4200-5559-7 | url=https://books.google.com/books?id=RgU9u9oUSDQC&pg=PA6 | pages=6–7}}</ref>
<ref name="Trudie du Toit 2007 p. 95">{{cite book | last=Trudie du Toit | first=L.B. | title=FCS Food Preparation L2 | publisher=Pearson Education South Africa | series=FET college series | year=2007 | isbn=978-1-86891-824-9 | url=https://books.google.com/books?id=rdlDftbyBpIC&pg=PA95 | page=95}}</ref>
<ref name="Ferrier Shuttleworth 1982 p. 60">{{cite book | last1=Ferrier | first1=S. | last2=Shuttleworth | first2=T. | title=The KidsFood Cookbook | publisher=James Lorimer Limited, Publishers | year=1982 | isbn=978-0-88862-596-0 | url=https://books.google.com/books?id=P6Jt4OPDkYMC&pg=PA60 | page=60}}</ref>
<ref name="Simpson 2010 p. 11">{{cite book | last=Simpson | first=A. | title=Food Porn Daily: The Cookbook | publisher=Sweetwater Press | year=2010 | isbn=978-1-59955-765-6 | url=https://books.google.com/books?id=R79vjevv0qoC&pg=PA11 | page=11}}</ref>
<ref name="Tsuji 2007">{{cite book | last=Tsuji | first=Shizuo | title=Japanese Cooking: A Simple Art | publisher=Kodansha International Limited | series=Cookery, Food and Drink Series |date=16 February 2007| isbn=978-4-7700-3049-8 | url=https://books.google.com/books?id=fby2Er0seMMC&pg=PA230 | pages=103, 230}}</ref>
<ref name="Johanson 2010 p. 18">{{cite book | last=Johanson | first=P. | title=Biofuels: Sustainable Energy in the 21st Century | publisher=Rosen Pub. | series=In the News | year=2010 | isbn=978-1-4358-3584-9 | url=https://books.google.com/books?id=AecoR7C-CckC&pg=PA18 | page=18}}</ref>
<ref name="Beasley 2003 p. 75">{{cite book | last=Beasley | first=R.W. | title=Beasley's Surgery of the Hand | publisher=Thieme | year=2003 | isbn=978-1-58890-161-3 | url=https://books.google.com/books?id=yl5BYZXIJfMC&pg=PA75 | page=75}}</ref>
<ref name="Castella2012">{{cite book|author=Krystina Castella|title=A World of Cake: 150 Recipes for Sweet Traditions from Cultures Near and Far; Honey cakes to flat cakes, fritters to chiffons, tartes to tortes, meringues to mooncakes, fruit cakes to spice cakes|url=https://books.google.com/books?id=Z20XOWapBCEC&pg=PT268|date=3 January 2012|publisher=Storey Publishing, LLC|isbn=978-1-60342-446-2|pages=268–270}}</ref>
<ref name="Fantozzi 2014">{{cite web | last=Fantozzi | first=Joanna | title=Eating Deep-Fried Maple Leaves Is Big in Japan | website=ABC News | date=9 October 2014 | url=https://abcnews.go.com/Lifestyle/eating-deep-fried-maple-leaves-big-japan/story?id=26034197 | access-date=24 May 2015}}</ref>
}}

==Further reading==
* {{cite book | last=Erickson | first=M.D. | title=Deep Frying: Chemistry, Nutrition, and Practical Applications | publisher=AOCS Press | year=2007 | isbn=978-1-893997-92-9 | url=https://books.google.com/books?id=I9kV-lKfOmwC }} 447 pages.
* {{cite web | last=Kosa | first=Frank | title=Backstory: If you can think of it, he can deep fry it | website=[[The Christian Science Monitor]] | date=16 October 2006 | url=https://www.csmonitor.com/2006/1016/p20s01-lifo.html | access-date=18 May 2015}}

==External links==
{{Wikisource}}
* {{Commons category-inline|Deep frying}}
* {{Cookbook-inline|Deep Fat Frying}}

{{Deep fried foods}}
{{Cooking Techniques}}
{{Authority control}}

{{DEFAULTSORT:Deep Frying}}
[[Category:Deep fried foods| ]]
[[Category:Cooking techniques]]
[[Category:Food preparation techniques]]
[[Category:Culinary terminology]]