Editing Convection oven

{{Short description|Appliance that heats food}}
{{Use dmy dates|date=August 2019}}
[[File:Tabletop convection oven.jpg|thumb|A tabletop convection oven cooking pork. For slower cooking, the [[Gridiron (cooking)|gridiron]] here has been reversed to place the meat low and far from the main heat source (at the top of the pot), although near the heat of the glass pot's bottom. Flipping the gridiron would raise the meat closer to the main heat source.]]

A '''convection oven''' (also known as a '''fan-assisted oven''', '''turbo broiler''' or simply a '''fan oven''' or '''turbo''') is an [[oven]] that has [[forced convection|fans to circulate air]] around food<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/convection+oven|title=Definition of CONVECTION OVEN|website=www.merriam-webster.com|date=7 July 2023 }}</ref> to create an evenly heated environment. In an oven without a fan, natural convection circulates hot air unevenly, so that it will be cooler at the bottom and hotter at the top than in the middle.<ref>{{cite web | last=Martin | first=Jonny | title=Gas Cookers vs Electric Cookers > Gas cooker cons > Less-even heat distribution in the oven| publisher=Which? | date=23 August 2024| url=https://www.which.co.uk/reviews/freestanding-cookers/article/gas-cookers-vs-electric-cookers-axJxK6t7cGGU }}</ref> Fan ovens cook food faster, and are also used in non-food, industrial applications.  Small countertop convection ovens for household use are often marketed as '''air fryers'''.

When cooking using a fan-assisted oven, the temperature is usually set lower than for a non-fan oven, often by {{cvt|20|C-change|sigfig=2}}, to avoid overcooking the outside of the food.

==Principle of operation==
Convection ovens distribute heat evenly around the food, removing the blanket of cooler air that surrounds food when it is first placed in an oven and allowing food to cook more evenly in less time and at a lower temperature than in a conventional oven.<ref>{{cite book |last=Ojakangas |first=Beatrice |title=Cooking with Convection: Everything You Need to Know to Get the Most from Your Convection Oven |date=2009 |author-link=Beatrice Ojakangas}}</ref>

== History ==

The first oven with a fan to circulate air was invented in 1914 but it was never launched commercially.<ref>{{cite magazine|url=https://archive.org/details/technicalworldma21chicuoft/page/403|title=Adding Pressure to Heat in Cooking|magazine=Technical World Magazine|date=May 1914|page=403}}</ref>

The first convection oven in wide use was the Maxson Whirlwind Oven, introduced in 1945.<ref>{{cite web|url=https://www.air-n-water.com/articles/convection-ovens-air-fryers.htm|title=Everything You Need to Know about Convection Ovens & Air Fryers|website=Air & Water|access-date=8 December 2017|archive-date=15 July 2018|archive-url=https://web.archive.org/web/20180715094548/https://www.air-n-water.com/articles/convection-ovens-air-fryers.htm|url-status=dead}}</ref>

Convection ovens have been in wide use since 1945.<ref>{{cite web|url=https://www.air-n-water.com/articles/convection-ovens-air-fryers.htm|title=Everything You Need to Know about Convection Ovens & Air Fryers|website=Air & Water|access-date=2020-08-17|archive-date=2018-07-15|archive-url=https://web.archive.org/web/20180715094548/https://www.air-n-water.com/articles/convection-ovens-air-fryers.htm|url-status=live}}</ref>

In 2006, [[Groupe SEB]] introduced the world's first air fryer, under the Actifry brand of convection ovens in the French market.<ref>lsa-conso .fr/produits/friteuse-actifry-seb,133832</ref><ref>lesechos.fr/2008/07/seb-defie-la-conjoncture-avec-linnovation-493611</ref><ref>federactive.com/histoire-du-groupe-seb.html</ref><ref>journaldunet. com/economie/industrie/1169062-actifry-smart-seb/1169706-8-millions-d-actifry-vendues-dans-le-monde</ref>

In 2010, [[Philips]] introduced the Airfryer brand of convection oven at the [[IFA Berlin]] consumer electronics fair.<ref>{{Cite web |last= |date=2010-09-03 |title=Philips debuts the Airfryer – crispy fries without the fat |url=https://newatlas.com/philips-debuts-airfryer/16229/ |access-date=2023-06-15 |website=New Atlas |language=en-US}}</ref><ref>{{Cite news |last=Morales |first=Christina |date=2022-01-25 |title=How the Air Fryer Crisped Its Way Into America's Heart |language=en-US |work=The New York Times |url=https://www.nytimes.com/2022/01/25/dining/air-fryer.html |access-date=2023-06-15 |issn=0362-4331}}</ref><ref name=exnovate>{{Cite web|url=https://www.exnovate.org/airfryer|title=History of the Air Fryer|website=exnovate.org|access-date=26 January 2019|archive-date=16 December 2019|archive-url=https://web.archive.org/web/20191216121453/https://www.exnovate.org/airfryer|url-status=dead}}</ref> By 2018, the term "air fryer" was starting to be used [[Generic trademark|generically]].<ref>{{cite web |url= https://www.genericides.org/trademark/airfryer |title= Has airfryer become a generic trademark? |access-date= February 17, 2021 |website= genericides.org |archive-date= April 24, 2021 |archive-url= https://web.archive.org/web/20210424223750/https://www.genericides.org/trademark/airfryer |url-status= live }}</ref>

In the United States convection ovens experienced a surge in popularity in the late 2010s and early 2020s with a reported 36% of U.S. households having one in 2020 and an estimated 60% of U.S. households having one in 2023. Food manufacturers have responded by adding air frying instructions on a number of products and pre air-fried products also coming to market.<ref>{{Cite web |last=Lucas |first=Amelia |date=2023-03-05 |title=Nestle, Tyson and other food giants bet on air fryer boom to grow sales |url=https://www.cnbc.com/2023/03/05/nestle-tyson-air-fryer-boom.html |access-date=2024-05-08 |website=CNBC |language=en}}</ref><ref>{{Cite news |last=Morales |first=Christina |date=2022-01-25 |title=How the Air Fryer Crisped Its Way Into America's Heart |url=https://www.nytimes.com/2022/01/25/dining/air-fryer.html |access-date=2024-05-08 |work=The New York Times |language=en-US |issn=0362-4331}}</ref>

In the UK, air fryers have surged in popularity since the early 2020s, with a 2024 study claiming that 1 in 5 Britons surveyed said that air fryers are their most commonly used cooking device. <ref>{{Cite web |date=2024-10-21 |title=Great British Kitchen Culture Index |url=https://ao.com/cooking/get-to-know |access-date=2024-12-10 |website=AO.com |language=en}}</ref>

== Design ==
A convection oven has a fan with a [[heating element]] around it. A small fan circulates the air in the cooking chamber.<ref>{{cite web|url=http://www.smeg.com/faq/ovens/what-s-the-difference-between-fan-and-fan-assisted-ovens/|archive-url=https://web.archive.org/web/20130507034832/http://www.smeg.com/faq/ovens/what-s-the-difference-between-fan-and-fan-assisted-ovens/|archive-date=2013-05-07|title=What's the difference between fan and convection ovens?|website=SMEG.com|access-date=20 July 2013}}</ref><ref>{{cite web|url=http://service.hoover.co.uk/advice-centre/built-in-appliances/ovens/troubleshooting/|title=Ovens Advice Centre|website=Hoover Advice Centre|access-date=20 July 2013|archive-url=https://web.archive.org/web/20130320183020/http://service.hoover.co.uk/advice-centre/built-in-appliances/ovens/troubleshooting/|archive-date=2013-03-20}}</ref>

One effect of the fan is to reduce the thickness of the stationary thermal [[boundary layer]] of cooler air that naturally forms around the food. The boundary layer acts as an insulator and slows the rate at which [[Heat transfer|heat is transferred]] to the food. By moving the cool air (''convecting'' it) away from the food the layer is thinned, and cooking is faster. To prevent overcooking before the middle is cooked, the temperature is usually reduced by about {{cvt|20|C-change|sigfig=2}} below the setting used for a non-fan oven. In a non-fan oven the temperature varies significantly in different places; a fan distributes hot air evenly for a uniform temperature.

Convection ovens may include additional [[radiant heat]] sources at the top and bottom of the oven, which provide immediate heat without the warmup time of a (natural or fan-assisted) convection oven.

== Effectiveness ==
A convection oven allows a reduction in cooking temperature compared to a conventional oven. This comparison will vary, depending on factors including, for example, how much food is being cooked at once or if airflow is being restricted, for example by an oversized [[baking tray]].{{Citation needed|date=December 2007}} This difference in cooking temperature is offset as the circulating air transfers heat more quickly than still air of the same temperature. In order to transfer the same amount of heat in the same time, the temperature must be lowered to reduce the rate of heat transfer in order to compensate.{{citation needed|date=March 2018}}

==Industrial convection ovens==
[[File:Industrial oven.jpg|thumb|An industrial convection oven used in the aircraft manufacturing industry]]

[[Hot air oven]]s are convection ovens used to sterilize medical equipment.

== Variants ==

Another form of convection oven has hot air directed at a high flow rate from above and below food that passes through the oven on a conveyor belt; it is called an impingement oven.<ref>{{cite web|url=https://patents.google.com/patent/US5934178A/en|title=US5934178A — Air impingement oven|via=Google Patents}}</ref><ref>{{cite news |title=Commercial Ovens |url=https://vanrooy.com.au/history-of-ovens/}}</ref><ref>{{cite web | title=The Science of Impingement: How it can speed up your cook time | publisher=Marlen |year=2022 | url=https://marlen.com/the-science-of-impingement-how-it-can-speed-up-your-cook-time/}}</ref> This cooks, for example, breaded products such as chicken nuggets or breaded chicken portions faster than a fan oven, and yields a crisp surface texture. Impinged air also prevents "shadowing" which occurs with infrared radiant heat sources. Impingement ovens can achieve a much higher heat transfer than a conventional oven.

Fully enclosed models can also use dual [[magnetron]]s,<ref>{{cite web |url=https://patents.google.com/patent/US8893705B2 |title=Speed cooking oven}}</ref> as used by microwave ovens. The most notable manufacturer of this type of oven is TurboChef. The differences between an impingement oven with magnetrons and a convection microwave oven are claimed to be cost, power consumption, and speed. Impingement ovens are designed to be used in restaurants, where speed is essential and power consumption and cost are less of a concern.

There are also [[convection microwave oven]]s which combine a convection oven with a [[microwave oven]] to cook food with the speed of a microwave oven and the [[Browning (chemical process)|browning]] ability of a convection oven.<ref>{{cite web | url=https://patents.google.com/patent/US11055563B2 |title=Heating cooker, cooking system, arithmetic device, and cooking support method}}</ref><ref>{{cite web |url=https://reviewed.usatoday.com/microwaves/content/ge-pvm9179sfss-over-the-range-microwave-review |title=Here, GE should stand for "General Excellence."}}</ref><ref>{{Cite web|url=https://www.dailydot.com/dot-recs/breville-combi-wave-3-in-1/|title=Breville Combi Wave 3-in-1 takes versatility to a whole new level|first=Jaime|last=Carrillo|date=10 June 2021|website=The Daily Dot}}</ref>

A [[combi steamer]] is an oven that combines convection functionality with [[superheated steam]] to cook foods even faster and retain more nutrients and moisture{{Citation needed|date=August 2024}}.

==Air fryer==

[[File:Air Fryer 5458.jpg|thumb|An air fryer]]

An ''air fryer'' is a small countertop convection oven that is said to simulate [[deep frying]] without submerging the food in oil.<ref name= Wired-worth>{{cite magazine|url=https://www.wired.com/story/air-fryers/|title=Are air fryers worth it?|magazine=Wired|date=2018-05-10|access-date=2019-01-08|archive-date=2019-03-19|archive-url=https://web.archive.org/web/20190319035022/https://www.wired.com/story/air-fryers/|url-status=live}}</ref><ref name="Clark" /> A [[Mechanical fan|fan]] circulates hot air<ref name= Wired-worth /> at a high speed, producing a crisp layer via browning reactions such as the [[Maillard reaction]]. Some product reviewers find that regular convection ovens or convection [[toaster oven]]s produce better results;<ref name= Wired-worth /> others say that air frying is essentially the same as convection baking,<ref>{{cite web |title=The Best Air Fryer |work=[[Wirecutter (website)|Wirecutter]] |publisher=[[The New York Times Company]] |url=https://www.nytimes.com/wirecutter/reviews/best-air-fryer/ |date=2022-03-22 |access-date=2021-04-02 |archive-url=https://web.archive.org/web/20200926195933/https://www.nytimes.com/wirecutter/reviews/best-air-fryer/ |archive-date=2020-09-26 |last1=Sullivan |first1=Michael}}</ref> while still others praise the devices for cooking faster, being easier to clean, and making it easier to produce crispy results than full size convection ovens.<ref name=GH>{{cite web|url=https://www.goodhousekeeping.com/appliances/a33403402/air-fryer-vs-convection-oven/|title=Air Fryer vs. Convection Oven: What's the Difference?|website=Good Housekeeping|date=29 April 2024 }}</ref> The original Philips Air fryer used radiant heat from a heating element just above the food and convection heat from a strong air stream flowing upwards through the open bottom of the food chamber, delivering heat from all sides, with a small volume of hot air forced to pass from the heater surface and over the food, with no idle air circulating as in a convection oven. A shaped guide directed the airflow over the bottom of the food. The technique was patented as Rapid Air technology.<ref>{{cite web |url= http://apds.nl/development-en/what-is-rapid-air-technology/ |title= What is Rapid Air Technology? |website= APDS |date= 10 June 2016 |access-date= 5 May 2023 |archive-date= 20 March 2022 |archive-url= https://web.archive.org/web/20220320132512/http://apds.nl/development-en/what-is-rapid-air-technology/ |url-status= dead }}</ref><ref name=exnovate/>

Traditional [[frying]] methods induce the Maillard reaction at temperatures of {{cvt|140|to|165|°C}} by completely submerging foods in hot oil, well above the boiling point of water. The air fryer works by circulating air at up to {{cvt|200|°C}} to apply sufficient heat to food coated with a thin layer of oil, causing the reaction.<ref name= "McGee">{{cite book| first= Harold |last= McGee| title= On Food and Cooking: The Science and Lore of the Kitchen| year= 2004| publisher= Scribners |isbn= 978-0-68480001-1 | chapter = The Maillard Reaction; Caramelization | pages = 656–57; 778–79}}</ref> Most air fryers have temperature and timer adjustments that allow precise cooking. Food is typically cooked in a basket that sits on a drip tray. For best results the basket must be periodically agitated, either manually or by the fryer mechanism. Convection ovens and air fryers are similar in the way they cook food, but air fryers are smaller and give off less heat to the room.<ref name="Clark">{{cite news| first= Melissa| last= Clark| title= 6 Tips for Using Your Air Fryer| work= [[The New York Times]]| date= April 1, 2019| url= https://www.nytimes.com/2019/04/01/dining/air-fryer.html| access-date= July 10, 2020| archive-date= November 8, 2020| archive-url= https://web.archive.org/web/20201108022515/https://www.nytimes.com/2019/04/01/dining/air-fryer.html| url-status= live}}</ref> There are several types of household air fryer:

; Paddle: In this type, a paddle machine moves throughout the heating chamber to move the air around more evenly. This is more convenient for the user because other types of air fryers require manual stirring throughout to ensure that all sides are fully cooked. <ref>{{Cite web |last=D’Costa |first=Roja |date=2021-03-11 |title=What Is An Air Fryer? - Types Of Air Fryer - All Kitchen Reviews |url=https://allkitchenreviews.com/what-is-an-air-fryer-types-of-air-fryer/ |access-date=2024-02-08 |website=allkitchenreviews.com |language=en-US}}</ref>
; Cylindrical basket: A cylindrical basket is a small, single function air fryer that includes a drawer with a removable basket. A fan circulates from the top, and the food is cooked through holes in the basket. It can accommodate {{convert|2.8|L|USqt|abbr=off}} of food or less on average. Because of its compact size, it preheats faster than other types of air fryers.<ref name=4types>{{Cite web |title=4 Types of Air Fryers |url=https://kitcheninfinity.com/kitchen/tool/appliance/air-fryer/types/ |access-date=2024-02-08 |website=Kitchen Infinity |date=7 December 2021 |language=en-US}}</ref>
; Countertop convection oven: Countertop convection ovens come with an air frying feature that work the same way as basket type air fryers. They usually have multiple trays or racks, so multiple things can be cooked at the same time. It holds {{convert|24|L|USqt|0|abbr=off}} of food on average. They are more versatile than single function type because they have multiple features like baking, rotisserie, grilling, frying, broiling, and toasting.<ref name=4types/>
; Halogen: This type of air fryer cooks food with a [[Halogen oven|halogen radiant heat source]] from above. The heat is spread evenly with a fan like other types of air fryers. This type is usually a large glass bowl with a hinged lid.<ref>{{Cite web |author1=Cynthia Lawrence |date=2022-11-26 |title=Air fryer vs halogen oven — which is cheaper? |url=https://www.tomsguide.com/face-off/air-fryer-vs-halogen-oven-which-is-cheaper |access-date=2024-02-08 |website=Tom's Guide |language=en}}</ref>
; Oil-less turkey fryer: This is a large, barrel-shaped air fryer used to cook whole turkeys and other large pieces of meat. It circulates air around the drum to cook the meat evenly.<ref>{{Cite web |last=D'Costa |first=Roja |date=2021-03-11 |title=What Is an Air Fryer? - Types of Air Fryer |url=https://allkitchenreviews.com/what-is-an-air-fryer-types-of-air-fryer/ |access-date=2024-02-08 |publisher=All Kitchen Reviews |language=en-US}}</ref>

===History===
Dutch engineer Fred van der Weij invented the air fryer in 2006, so that he could cook crispy food with little oil.<ref>{{Cite web |date=2025-05-14 |title=BBC World Service - Witness History, How the air fryer was invented, 'My dad invented the air fryer' |url=https://web.archive.org/web/20250514222839/https://www.bbc.co.uk/programmes/p0j9j11t |access-date=2025-05-14 |website=web.archive.org}}</ref> Four years later, van der Weij took his invention to [[Philips]], who launched the ''Airfryer'' in 2010.<ref>{{Cite web |date=2025-05-14 |title=The company that launched the air fryer {{!}} Business Leader |url=https://web.archive.org/web/20250514222800/https://businessleader.co.uk/content/article/554/the-company-that-launched-the-air-fryer |access-date=2025-05-14 |website=web.archive.org}}</ref> Philips gave the name ''Rapid Air technology'' to the RUSH (''Radiant and UpStream Heatin''g) technology developed by APDS Development during the development of the ''Airfryer''.<ref>{{Cite web |date=2023-03-21 |title=What is Rapid Air Technology? - APDS |url=https://web.archive.org/web/20230321064924/http://apds.nl/development-en/what-is-rapid-air-technology/ |access-date=2025-05-14 |website=web.archive.org}}</ref>

== References ==
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==External links==
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[[Category:20th-century inventions]]
[[Category:Convection]]
[[Category:Ovens]]