# Crock pot cooking question **URL:** \ **Category:** Cafe Society\ **Created:** [August 28, 2008, 6:29pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583 "2008-08-28T18:29:15Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Euthanasiast](https://avatars.discourse-cdn.com/v4/letter/e/6f9a4e/32.png) [@Euthanasiast](https://boards.straightdope.com/u/Euthanasiast)\ **Post date:** [August 28, 2008, 6:29pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/1 "2008-08-28T18:29:15Z")
So how long after the food is done can I leave it on the warm setting in my crock pot? I seem to recall (memory may not be entirely accurate) a family member having the slow cooker on 24/7 and simply adding ingredients to it as it was needed. This means that (if I am correct) food would have been left warming for many days, and eaten at leisure. Then when the pot was getting low, you’d simply check to see what was needed and toss it in there (a can of corn, peas, etc.). Is that possible, or are we asking for trouble here? Did a family member of mine keep food in a crock pot 24/7? ---
**Author:** ![hellpaso](https://avatars.discourse-cdn.com/v4/letter/h/ecae2f/32.png) [@hellpaso](https://boards.straightdope.com/u/hellpaso)\ **Post date:** [August 28, 2008, 6:38pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/2 "2008-08-28T18:38:18Z")
i don’t think it would be safe to leave it indefinitely. i’ve kept stuff on warm for a few hours (mashed taters, queso). most other things would start to overcook, i would think. and as soon as it starts to cool, i always make sure to get it refrigerated within a two hour window. too many thingies start growing at a warm, not hot, temperature. ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [August 28, 2008, 6:39pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/3 "2008-08-28T18:39:22Z")
It may or may not be safe, depending on the crock pot: Some of the newer crockpots seem to cook at a hotter temperature, probably because manufacturers are concerned about food safety. You can check the temperature of your crockpot this way: Place 2 quarts of water in your crockpot Cover and heat on low for 8 hours Lift the lid and immediately check the water temperature with an accurate thermometer The temperature of the water should be 185 degrees Fahrenheit. If the temperature is higher foods may overcook and you should reduce the overall cooking time. If the temperature is lower your foods will probably not reach a safe temperature quickly enough, and the crockpot should be discarded From [here](http://busycooks.about.com/library/weekly/aa022103a.htm). ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 28, 2008, 6:47pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/4 "2008-08-28T18:47:19Z")
Wow, **8 hours**! Seems like you would be able to find out after one hour, maximum. I wonder why that site recommends eight? It is funny that they want you to heat it up for so long, and then _immediately_ check the temperature. > [@](#): > > The temperature range in which foodborne bacteria can grow is known as the danger zone. This is typically considered to be between 40°F (4.4°C) and 140°F (60°C)[1], though often 45°F (7.2°C) is considered the lower temperature of the range[2]. According to the 2005 FDA Food Code, the danger zone is defined as 41°F - 135°F (5°C - 57°C). Potentially hazardous food should not be stored at temperatures in this range in order to prevent foodborne illness. Just to cite the Danger Zone: > **[Danger zone (food safety)](https://en.wikipedia.org/wiki/Danger_zone_(food_safety))** > > The danger zone is the temperature range in which food-borne bacteria can grow. Food safety agencies, such as the United States' Food Safety and Inspection Service (FSIS), define the danger zone as roughly 4 to 60 °C (40 to 140 °F). The FSIS stipulates that potentially hazardous food should not be stored at temperatures in this range in order to prevent foodborne illness\[a\] and that food that remains in this zone for more than two hours should not be consumed. Foodborne microorganism Food-borne ... ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [August 28, 2008, 6:47pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/5 "2008-08-28T18:47:47Z")
[QUOTE=hellpaso] i don’t think it would be safe to leave it indefinitely. i’ve kept stuff on warm for a few hours (mashed taters, queso). most other things would start to overcook, i would think. and as soon as it starts to cool, i always make sure to get it refrigerated within a two hour window. too many thingies start growing at a warm, not hot, temperature. [/QUOTE] Nitpick, you don’t want to just get it into the fridge in two hours. It needs to go from above 150\* to below 40 in two hours. So if you want to be safe, after you put it in the fridge you should stir it from time to time or depending on what you are cooking (chili for example) the center could take several hours to get out of the danger zone. \*Not sure about that upper limit, in fact in changes depending on the specific food. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 28, 2008, 6:58pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/6 "2008-08-28T18:58:02Z")
[QUOTE=Joey P] \*Not sure about that upper limit, in fact in changes depending on the specific food. [/QUOTE] According to [this cite](http://www.metrokc.gov/health/foodsfty/foodtemps.htm), 140F is the “hot holding temperature” for all hot food, while the minimum internal temperature is 145F for fish, shellfish, lamb, beef, and pork. Ground beef, and poultry are 155F and 165F respectively. ETA: From [http://www.netwellness.com/healthtopics/poison/danger.cfm](http://www.netwellness.com/healthtopics/poison/danger.cfm) > [@](#): > > If you have seen the “danger zone” for food given as two different ranges: 40 degrees to 140 degrees and more recently 41-135 degrees, don’t be confused. What’s most important to remember is the simple notion behind it: Keep hot foods hot and cold foods cold. > > The “danger zone” concept indicates that foods within the temperature range are susceptible to growth of bacteria and production of toxins, and can be dangerous if held in that range too long. For years, the zone was marked by 40 degrees Fahrenheit at the bottom end and 140 degrees at the top. > > However, more recent research and experience shows that danger zone is a bit narrower than we thought. As long as foods are kept colder than 41 degrees or hotter than 135 degrees, they’re deemed to be safe. So, in 2003 the Food and Drug Administration amended its Food Code to address the issue. Curriculums for food service training have also adopted the change, as has the Ohio Food Code. ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [August 28, 2008, 7:06pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/7 "2008-08-28T19:06:01Z")
[QUOTE=Santo Rugger] Wow, **8 hours**! Seems like you would be able to find out after one hour, maximum. I wonder why that site recommends eight? [/QUOTE] I suspect it is to simulate a fully loaded crock pot, unstirred. If you put cold food into a crock pot and set it on low, how long will it take for the center of the load to reach the set point of the crock pot? My WAG is at least an hour. How this relates to heating plain water is anyone’s guess, due to convection and such. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 28, 2008, 7:26pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/8 "2008-08-28T19:26:37Z")
185F is 85C. Two liters (kilograms) of water (C[sub]p[/sub]=4.18kJ/kg) in a 180 W crock pot would go from 25C to 85C (delta T = 60) in 2,787 seconds, or 46 minutes. 2_4.18_60/180/60 8 hours would make sense for a full load of, say, chili, but certainly not for water, as the natural convection would be much stronger than the resistance due to viscosity (especially since they heat from the bottom. \*\*This assumes no heat loss to the surroundings. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [August 28, 2008, 8:07pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/9 "2008-08-28T20:07:40Z")
[QUOTE=masterofnone] I suspect it is to simulate a fully loaded crock pot, unstirred. If you put cold food into a crock pot and set it on low, how long will it take for the center of the load to reach the set point of the crock pot? My WAG is at least an hour. How this relates to heating plain water is anyone’s guess, due to convection and such. [/QUOTE] I’d be willing to bet if you put a crock put full of cold beef stew, in one hour the center of a potato or carrot in the middle of the crock, would still be below 100 degrees. But that’s just my WAG, I’ve never really measured. As for the danger zone, I’ve always had a question about that. Is the 2 hour limit cumulative? If it takes me 1.5 hours to get it from 135 to 41, do I only get 30 minutes to reheat it? ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [August 28, 2008, 8:08pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/10 "2008-08-28T20:08:19Z")
The more I think about that reccomendation, the less sense it makes. It’s really not very informative if it reaches 185F in eight hours, and water will heat much faster than most things due to conduction and convection. What is important is that the food reaches 140F within and hour and a half to two hours (depending on the source). Once it gets to that temp, as long as it stays there, you’re pretty safe. Thermophiles can grow at that temp, but I’ve never heard of them being harmful. I can’t imagine the food would taste good cooking constantly for days though. Seems like you’d end up with nasty brown mush no matter what you were cooking. ---
**Author:** ![Fish](https://avatars.discourse-cdn.com/v4/letter/f/bc8723/32.png) [@Fish](https://boards.straightdope.com/u/Fish)\ **Post date:** [August 28, 2008, 8:16pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/11 "2008-08-28T20:16:35Z")
Now if you put your crock pot on a treadmill… ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [August 28, 2008, 8:24pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/12 "2008-08-28T20:24:01Z")
[QUOTE=Santo Rugger] Wow, **8 hours**! Seems like you would be able to find out after one hour, maximum. I wonder why that site recommends eight? It is funny that they want you to heat it up for so long, and then _immediately_ check the temperature. [/QUOTE] Because as soon as you lift the lid, the temperature starts dropping. The ‘immediate’ applies to the time between lifting the lid and taking the temp. If you lift the lid and then start asking yourself “where did I leave that thermometer?” you won’t get an accurate measurement, you’ll get a lower one. ---
**Author:** ![GilaB](https://avatars.discourse-cdn.com/v4/letter/g/8e7dd6/32.png) [@GilaB](https://boards.straightdope.com/u/GilaB)\ **Post date:** [August 28, 2008, 8:24pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/13 "2008-08-28T20:24:02Z")
Being a Sabbath-observant Jew, there are several recipes that I will leave in the crockpot for up to 24 hours, so that we can have a hot lunch on Saturday that I put up to cook on Friday afternoon. I do this every weekend in the cooler months, as do the majority of the people I know, and we haven’t had a problem yet. Of course, this is not on the ‘warm’ setting, but on a setting high enough that everything is kept cooking-temperature hot. ---
**Author:** ![masterofnone](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@masterofnone](https://boards.straightdope.com/u/masterofnone)\ **Post date:** [August 28, 2008, 8:24pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/14 "2008-08-28T20:24:09Z")
[QUOTE=Joey P] As for the danger zone, I’ve always had a question about that. Is the 2 hour limit cumulative? If it takes me 1.5 hours to get it from 135 to 41, do I only get 30 minutes to reheat it? [/QUOTE] Yes, that is cumulative. However, it’s not a magic number. It’s not like there is no danger at 1:59, and the food will kill you at 2:01. It’s a guestimate of what is likely safe based on reported cases of food poisoning. The minimum doubling time for most bacteria is 20 minutes in optimum conditions, so after 2 hours you will have 64x the number of bacteria that you started with. It gets progressively more dangerous the more doubling times the food stays in the danger zone, as growth is logrythmic. Of course, food is seldom optimal for bacterial growth, so the doubling times will be lengthened depending on how far from optimal the food is in terms of salt/sugar content, acidity, nutrient levels, spices, etc. If you’re cooking pickled garlic and lemon soup, you can pretty much ignore the danger zone. (and forget about poisoning your dinner guests, as you won’t have any!) ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [August 28, 2008, 8:32pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/15 "2008-08-28T20:32:46Z")
[QUOTE=masterofnone] Yes, that is cumulative. However, it’s not a magic number. It’s not like there is no danger at 1:59, and the food will kill you at 2:01. It’s a guestimate of what is likely safe based on reported cases of food poisoning. [/QUOTE] That makes sense. You know, I’m ServSafe Certified and deal with the local heath inspector 2 to 3 times a year. While they all talk about the danger zone, the 2 hour limit, time and temperature abuse. You’d think they’d talk about that number being cumulative. Especially with soups and other foods that may get heated and cooled every day over the course of a week (or more). ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 28, 2008, 8:33pm UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/16 "2008-08-28T20:33:45Z")
[QUOTE=Yllaria] Because as soon as you lift the lid, the temperature starts dropping. The ‘immediate’ applies to the time between lifting the lid and taking the temp. If you lift the lid and then start asking yourself “where did I leave that thermometer?” you won’t get an accurate measurement, you’ll get a lower one. [/QUOTE] Only if the heat transfer rate out of the crock pot is greater than 180W. I’m actually writing a program for work right now, I’ll run it with crock pot specific numbers when I’m done with it. ---
**Author:** ![Rico](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rico/32/3582_2.png) [@Rico](https://boards.straightdope.com/u/Rico)\ **Post date:** [August 29, 2008, 7:14am UTC](https://boards.straightdope.com/t/crock-pot-cooking-question/461583/17 "2008-08-29T07:14:24Z")
\ Maybe this will heat up a little better in _Cafe Society_. GQ \> CS \