Slow cooker: Difference between revisions

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{{short description|Countertop electrical cooking appliance used to simmer food}}

In food preparation, a '''crock-pot''' (also crock pot) is the name given by some manufacturers to their brands of ''[[slow cooker]]s''. It is a trademarked term in many countries, but is often used generically. When used to refer to the trademarked brand of cooker, both words are capitalized.

{{redirect-distinguish|Crock-pot|Crackpot (disambiguation){{!}}Crackpot<!--deliberate link to dab page-->}}

[[File:Crock pot.jpg|thumb|A modern, oval-shaped slow cooker]]

This type of slow cooker consists of a pot (typically 10" across and similarly high) made of fired clay and usually glazed, surrounded by a housing, usually metal, containing a [[thermostat|thermostatically]] controlled [[electric]] heating element. A crockpot has a loosely fitting lid of glass or plastic to keep in the fluids. Cooking is done at atmospheric pressure and up to the boiling point of the fluid (typically 212 F / 100 C). Many crockpots have two settings for power. The physics of [[boiling_point|boiling] prohibit a temperature rise above the boiling point while there is still liquid changing into stem (most of which condenses back into the crock).

A '''slow cooker''' (also known as a '''crock-pot''' after a trademark owned by [[Sunbeam Products]], but sometimes used [[Generic trademark|generically]] in the [[English-speaking world]]) is a [[countertop]] electrical cooking [[Small appliance|appliance]] used to [[simmering|simmer]] at a [[low-temperature cooking|lower temperature]] than other cooking methods, such as baking, boiling, and frying.<ref>Gisslen, Wayne (2011). ''Professional cooking'', 7th ed., John Wiley & Sons, Inc. p. 71</ref> This facilitates unattended cooking for many hours of dishes that would otherwise be boiled: [[pot roast]], soups, stews and other dishes (including beverages, desserts and dips).

In use, the food is placed inside the pot, immersed in water, the lid applied, and the unit switched on. Cooking times vary with the recipe and with the food quantity, but are typically several hours. Temperatures are low in comparison with traditional ovens, and with broiling and baking. Cooking is sufficiently slow that, if the food is not removed promptly at the specified time, little harm is done.

==History==

The water and its proper level is important, for it serves both as the heat [[conduction]] mechanism between the pot walls and the food, and as the flavoring (herbs and spices) distribution method and a 'basting' mechanism. No stirring is required (or allowed); removing the lid during cooking causes significant cooking delays. The lid is important as it prevents escape of hot water vapor which would, if permitted, lead to lowering the internal water level and to loss of heat.

Slow cookers achieved popularity in the United States during the 1940s, when many women began to work outside the home.<ref name="Smith"/> They could start [[dinner]] cooking in the morning before going to work and finish preparing the meal in the evening when they came home.

The Naxon Utilities Corporation of [[Chicago]], under the leadership of electrical engineer [[Irving Naxon]] (born Irving Nachumsohn), developed the Naxon Beanery All-Purpose Cooker for the purposes of cooking a bean meal.<ref name="Smith">{{cite web |last1=Delgado |first1=Michelle |title=A Brief History of the Crock Pot |url=https://www.smithsonianmag.com/innovation/brief-history-crock-pot-180973643/ |website=Smithsonian |access-date=15 December 2019 |date=26 November 2019}}</ref> Naxon was inspired by a story related by his mother, how in her native [[Lithuania]]n town his grandmother made a traditional Jewish stew called [[cholent]], which took several hours to cook in an oven.<ref name="Smith"/><ref>{{cite web|author=Naxon, Lenore|title=My Dad, the Inventor of the Crock Pot|work=Beyond Bubbie|date=8 April 2013|access-date=2 May 2013|url=http://www.beyondbubbie.com/my-dad-the-inventor-of-the-crock-pot/|archive-url=https://web.archive.org/web/20130701055537/http://www.beyondbubbie.com/my-dad-the-inventor-of-the-crock-pot/|archive-date=1 July 2013}}</ref><ref name = "CNET">{{cite web| url = https://www.cnet.com/news/from-humble-to-high-tech-a-slow-cooker-history/| title = From humble to high tech, a slow cooker history| last = Pilkington| first = Katie| date = January 31, 2014| publisher = [[CNET]]| access-date = December 29, 2016}}</ref> A 1950 advertisement shows a slow cooker called the "Simmer Crock" made by the Industrial Radiant Heat Corporation of [[Gladstone, New Jersey]].<ref>{{cite book|url=https://books.google.com/books?id=IkYEAAAAMBAJ&q=industrial+radiant+heat+corp.+Gladstone+NJ&pg=PA2 |title=The Rotarian |page=2 |date= April 1950|access-date=2016-11-27}}</ref>

Recipes for these cookers must be adjusted to compensate for the nature of the cooking. Often water must be decreased. Most (probably all) come with recipe booklets; many cookbooks and websites with crock pot recipes are available. A small number of cookbooks seek to make complete dishes in a crockpot using fewer than five ingredients while others treat the crockpot as a serious piece of culinary equipment capable of producing gourmet meals. With some experience, timings and recipe adjustments can be successfully made for many recipes not originally intended for these cookers.

[[Rival (consumer products company)|The Rival Company]] of Kansas City, Missouri, bought Naxon in 1970, acquiring Naxon's 1940 patent for the bean simmer cooker.<ref name="Smith"/> Rival asked inventor Alex MacMaster, from Boonville, Missouri, to develop Naxon's bean cooker into a large scale production model that could cook an entire family meal, going further than just cooking a bean meal. Alex also designed and produced the mass-production machines for Rival's manufacturing line of the Crock-Pot. The cooker was then reintroduced under the trademark "Crock-Pot" in 1971.<ref name="Smith"/> In 1974, Rival introduced removable [[stoneware]] inserts, making the appliance easier to clean. {{As of|2016|post=,}} the Crock-Pot brand belongs to [[Newell Brands]].

''Safety:'' Cooking temperatures are lower than many other cooking methods, and cooking times are lengthy, so some have been concerned about the growth of micro-organisms. If the temperature control is working correctly, and if food is not left to stand more than briefly at room temperature, there is little problem. Fill the pot, add water, and promptly turn the unit on; this will avoid such problems.

Other brands of this appliance, past and present, include [[Cuisinart]], [[General Electric|GE]], [[Hamilton Beach Brands|Hamilton Beach]], [[KitchenAid]], [[Magic Chef]], [[West Bend Housewares]], and the now-defunct American Electric Corporation.

If the starting food ingredients are frozen, it may take a long time for the pot to rise to proper cooking temperature. During this prolonged temperature climb, the microbes in the food can multiply. The microbes will be eventually entirely killed before the food is served, and so will themselves present little problem. But some microbes produce [[toxin]]s which remain even after the microbes have expired. Most such are proteins which are themselves destroyed by the heat of cooking; but some of these cannot be destroyed by cooking -- as for example [[botulinism]] toxin. In actual practice, most such heat resistant toxins are produced by anaerobic microbes which cannot survive in the presence of oxygen (eg, boulinism toxin). The combination of contact with the atmoshphere (ie, with oxygen) and cooking heat disposes of nearly all such problems. As in all cases with frozen food (crock pots are not unique in this regard), one safeguard is to defrost frozen ingredients at low temperatures at which microbes don't do well (ie, in the refrigerator), or to defrost them more quickly (eg, in a microwave or a conventional oven), before putting them into the crock pot.

==Design==

[[Perpetual_stew|Perpetual stews]] should not be left in the crock as the crock cools very slowly.

[[File:Crock pot parts.jpg|thumb|right|A new slow cooker. This one has a removable ceramic "crock" (upper left), glass lid (lower left), and heater housing (right) with push-button controls, instead of the original single knob.]]

[[File:Oval Crock Pot2.jpg|thumb|right|An oval-shaped slow cooker with [[membrane switch]] push-button controls and a digital timer]]

A basic slow cooker consists of a lidded round or oval [[Cookware and bakeware|cooking pot]] made of [[ceramic glaze|glazed]] [[ceramic]] or [[porcelain]], surrounded by a housing, usually metal, containing an electric heating element. The lid is often made of glass, and seated in a groove in the pot edge; condensed vapor collects in the groove and provides a low-pressure seal to the atmosphere. The contents of a crock pot are effectively at [[atmospheric pressure]], despite the water vapor generated inside the pot. A slow cooker is quite different from a [[pressure cooker]] and presents no danger of an abrupt pressure release.

The "[[crock (dishware)|crock]]", or ceramic pot, acts as both a cooking container and a [[thermal reservoir]]. Slow cookers come in capacities from {{convert|500|mL|USoz|abbr=on}} to {{convert|7|L|USqt|abbr=on}}. Because the heating elements are generally located at the bottom and often also partway up the sides, most slow cookers have a minimum recommended liquid level to avoid uncontrolled heating. Some newer models have coated aluminum or steel "crocks" which, while not as efficient as ceramic at retaining heat, do allow for quicker heating and cooling, as well as the ability to use the "crock" on the stove top to brown meat prior to cooking.

''Warning:'' Because these cookers are portable/movable, contain large quantities of hot food and water, and because they are left unattended during long cooking times, they are dangerous around small children and exploratory pets. Cooking areas should be blocked off -- effectively -- if either might be present unattended.

Many slow cookers have two or more heat settings, ''e.g.'', low, medium, high, and sometimes a "keep warm" setting; some have continuously variable power. Early slow cookers had no temperature control and delivered a constant heat to the contents. The temperature of the contents rises until it reaches the boiling point, at whereupon the energy goes into gently boiling the liquid closest to the hot surface. At a lower setting, it may just simmer at a temperature below the boiling point. While many basic slow cookers still operate in this manner, newer models have electronics for precise temperature control, delayed cooking starts and control via a computer or mobile device.

A check of Usenet and News articles failed to find one article in which a crockpot started a fire. A minority seem to be frightened that the crockpot will cause a fire when they are not looking. The majority of responses point out that crockpots are designed for long hours of unattended cooking, that they leave appliances on all the time without incident, and that they have never had a problem with their crockpot. Many users report that burning food is nearly impossible as overcooking a stew merely turns it to an edible mush. The most likely source of a fire using a crockpot would be a shorting of the cord (a hazard with any electrical appliance that can be avoided using the right fuses and/or circuit breakers, not keeping mice or animals which chew cords in the kitchen and not testing out knives on said cord). Any issues with the heat may be dealt with by isolating the appliance from surrounding flammables on a large metal plate or stone surface.

==Operation==

To use a slow cooker, the cook places raw food and a liquid, such as [[Stock (food)|stock]], water, or wine, in the slow cooker. Some recipes call for pre-heated liquid. The cook puts the lid on the slow cooker and turns it on. Some cookers automatically switch from cooking to [[food warmer|warming]] (maintaining the temperature at {{convert|71|-|74|C}}) after a fixed time or after the internal temperature of the food, as determined by a probe, reaches a specified value.

The heating element heats the contents to a steady temperature in the {{convert|79|-|93|C}} range. The contents are enclosed by the crock and the lid, and attain an essentially constant temperature. The vapor that is produced at this temperature [[Condensation|condenses]] on the bottom of the lid and returns as liquid, into which some water-soluble vitamins are leached.<ref>{{cite web|author=<!--Not stated-->|url=http://recipes.howstuffworks.com/slow-cooker-questions.htm |title=Slow Cooker Questions|date=13 November 2007 |work=How Stuff Works |access-date=18 September 2024}}</ref>

The liquid transfers heat from the pot walls to its contents, and also distributes flavors. The slow cooker's lid is essential to prevent the warm vapor from escaping, taking heat with it and cooling the contents.

Basic cookers, which have only high, medium, low, or keep warm settings and must be turned on and off manually. More advanced cookers have computerized timing devices that let a cook program the cooker to perform multiple operations, such as two hours high, followed by two hours low, followed by warm, and to delay the start of cooking.

Because food cooked in a slow cooker stays warm for a long time after it is switched off, people can use the slow cookers to take food elsewhere to eat without reheating. Some slow cookers have lids that seal to prevent their contents from spilling during transport.

==Recipes==

Recipes intended for other cooking methods must be modified for slow cookers. Quantities of liquids may need adjustment, as there is a little [[evaporation]], but there should be enough liquid to cover the food{{citation needed|date=August 2022}}. Many published recipes for slow cookers are designed primarily for convenience and use few ingredients, and often use prepared sauces or seasonings. The long, moist cooking is particularly suitable for tough and cheap cuts of meat including [[Cut of pork#Shoulder|pork shoulder]], [[chuck steak]] and [[brisket]]. For many slow-cooked dishes, these cuts give better results than more expensive ones. They are also often used to cook while unattended, meaning the cook can fill the pot with its ingredients and come back several hours later to a ready meal.

==Advantages==

Cheaper cuts of meat with [[connective tissue]] and lean muscle fibers are suitable for [[stew]]ing, and produce tastier stews than those using expensive cuts,<ref>{{cite news|first = Heston|last = Blumenthal|author-link= Heston Blumenthal|url = https://www.theguardian.com/lifeandstyle/2002/dec/07/foodanddrink.shopping|title = Take your time &#124; Life and style|newspaper = [[The Guardian]]|date = 7 December 2002|access-date = 9 February 2010}}</ref> as long slow cooking softens connective tissue without toughening the muscle. Slow cooking leaves gelatinized tissue in the meat, so that it may be advantageous to start with a richer liquid.

The low temperature of slow-cooking makes it almost impossible to burn even food that has been cooked too long. However, some meats and most vegetables become nearly tasteless or "raggy" if over-cooked.

Food can be set to slow-cook before leaving for the day so it is ready on return. Many homeowners with [[Photovoltaic system|rooftop solar panels]] switch to slow cooking because it draws under 1&nbsp;[[Kilowatt|kW]] of power and can therefore be powered entirely by 1–2&nbsp;kW panels during the day.<ref>{{cite news|first = Sophie|last = Christie|date = 22 November 2013|access-date = 5 December 2016|newspaper = [[The Daily Telegraph]]|title = How much cheaper is a slow cooker than an oven?|url = https://www.telegraph.co.uk/finance/personalfinance/household-bills/10449285/Slow-cooker-vs-oven-How-much-cheaper.html}}</ref> Some models include timers or thermostats that bring food to a given temperature and then lower it. With a timerless cooker it is possible to use an external timer to stop cooking after a set time, or both to start and stop.

Cooking the meal in a single pot reduces water waste resulting from cleaning multiple dishes, and the low cooking temperature and glazed pot make cleaning easier than conventional high-heat pots.

==Disadvantages==

Some vitamins and other trace nutrients are lost, particularly from vegetables, partially by [[enzyme]] action during cooking and partially due to heat degradation.{{Citation needed|date=September 2012}} When vegetables are cooked at higher temperatures these enzymes are rapidly [[Denaturation (biochemistry)|denatured]] and have less time to act during cooking. Since slow cookers work at temperatures well below boiling point and do not rapidly denature enzymes, vegetables tend to lose trace nutrients.{{Citation needed|date=September 2012}} [[Blanching (cooking)|Blanched]] vegetables, having been exposed to very hot water, have already had these enzymes rendered largely ineffective, so a blanching or sauteing pre-cook stage leaves more vitamins intact.<ref name="University of Georgia">{{cite web |publisher=University of Georgia |access-date=2010-02-10 |url=http://www.uga.edu/nchfp/how/freeze/blanching.html |title=National Center for Home Food Preservation}}</ref> This is often a smaller nutrient loss than over-boiling and can be lessened to an extent by not removing the lid until the food is done.

Slow cookers do not provide sufficient heat to compensate for loss of moisture and heat due to frequent removal of the lid, ''e.g.'', to add and remove food in [[perpetual stew]]s, ([[pot-au-feu]], [[olla podrida]]). Added ingredients must be given time to cook before the food can be eaten.

==Hazards==

===Scalding===

Slow cookers are less dangerous than ovens or stove tops due to their lower operating temperatures and closed lids. However, they still contain a large amount of foods and liquids at temperatures close to boiling, and they can cause serious scalds if spilled.

===Poisoning concerns===

Slow cookers should not be used to cook dried [[kidney bean]]s and other legume seeds.<ref>{{cite web |year=2012 |title=Bad Bug Book (2012) |url=https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf |archive-url=https://web.archive.org/web/20130418013247/http://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf |url-status=dead |archive-date=April 18, 2013 |access-date=9 May 2022 |work=Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin |publisher=Food and Drug Administration |quote=Slow cookers should not be used to cook these beans or dishes that contain them. Studies of casseroles cooked in slow cookers revealed that the food often reached internal temperatures of only 75°C or less, which is inadequate for destruction of the toxin.}}</ref> These foods contain a highly toxic [[lectin]], [[phytohaemagglutinin|phytohemagglutinin]],<ref>{{cite web|title=Bad Bug Book (2012)|work=Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin|url=https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|archive-url=https://web.archive.org/web/20130418013247/http://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|url-status=dead|archive-date=April 18, 2013|publisher=Food and Drug Administration|access-date=2 February 2022|year=2012|quote=Among the lectins known to have toxic effects is phytohaemagglutinin which occurs at relatively high levels in the seeds of legumes eg beans}}</ref> making as few as four raw beans toxic.<ref>{{cite web |year=2012 |title=Bad Bug Book (2012) |url=https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf |archive-url=https://web.archive.org/web/20130418013247/http://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf |url-status=dead |archive-date=April 18, 2013 |access-date=2 February 2022 |work=Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin |publisher=Food and Drug Administration |quote=Toxic dose: As few as four or five raw beans can trigger symptoms.}}</ref> This lectin is only deactivated by long soaking, then boiling in fresh water at {{convert|100|C}} for at least thirty minutes.<ref>{{cite web|title=Bad Bug Book (2012)|work=Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin|url=https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|archive-url=https://web.archive.org/web/20130418013247/http://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|url-status=dead|archive-date=April 18, 2013|publisher=Food and Drug Administration|access-date=2 February 2022|year=2012|quote=Studies done by British scientists suggest that beans should be soaked in water for at least 5 hours,the water poured away, and the beans boiled in fresh water for at least 30 minutes}}</ref> Information published by the United States Food and Drug Administration states that slow cookers should not be used to cook bean containing dishes.<ref>{{cite web|title=Bad Bug Book (2012)|work=Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin|url=https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|archive-url=https://web.archive.org/web/20130418013247/http://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf|url-status=dead|archive-date=April 18, 2013|publisher=Food and Drug Administration|access-date=9 May 2022|year=2012|quote=Slow cookers should not be used to cook these beans or dishes that contain them. Studies of casseroles cooked in slow cookers revealed that the food often reached internal temperatures of only 75°C or less, which is inadequate for destruction of the toxin.}}</ref> Commercially canned beans are fully cooked and are safe to use. Pressure cooking also deactivates the lectins.<ref>{{Cite web |last=Kotifani |first=Aislinn |date=2020-03-06 |title=The Truth About Lectins—Why Beans Have Gotten a Bad Rap - Blue Zones |url=https://www.bluezones.com/2020/03/the-truth-about-lectins-why-beans-have-gotten-a-bad-rap/,%20https://www.bluezones.com/2020/03/the-truth-about-lectins-why-beans-have-gotten-a-bad-rap/ |access-date=2022-05-10 |website=Blue Zones |language=en-US}}</ref>

==See also==

{{Portal|Food}}

{{div col|colwidth=30em}}

* [[Beanpot]]

* [[Carryover cooking]]

* [[Combi steamer]]

* [[Haybox]]

* [[Hot pot]]

* [[List of cooking appliances]]

* [[Low-temperature cooking]]

* [[Rice cooker]]

* [[Remoska]]

* [[Sous vide]]

* [[Thermal cooking]]

{{div col end}}

==References==

{{Reflist}}

==Further reading==

{{Commons category|Slow cookers}}

* {{cite book| title=The Chef and the Slow Cooker |author=Hugh Acheson |year=2017 |isbn=978-0451498540 |publisher=Clarkson Potter }}

{{cooking techniques}}

{{Authority control}}

{{DEFAULTSORT:Slow Cooker}}

[[Category:Cooking appliances]]

[[Category:Cooking vessels]]

[[Category:Cooking techniques]]