Is it bad to leave the crock pot on “warm” (not low) all day?

Question

I just bought all the ingredients to make a soup in the crock pot. I was planning on having it cook all day, but I just realized the recipe only calls for it to cook on low for 3-4 hours. If I cook it on low for 3-4 hours, and then put it on warm before I leave for work, will it be a bacteria minefield or will it be warm enough to keep the food safe from bacteria?

Answer 1

I suspect "warm" is meant to maintain temperature, rather than raise it. My crock pots are too ancient to have anything other than "high" and "low", so I can't assert any real authority. However, if you reach 145F within the first hour at the highest setting, then keep it at "warm", and test the temperature after about 30 minutes with an instant-read thermometer and it stays around 140-160F, you'll probably be fine. Personally, I'd test the temperature first by cooking water.

If the temperature stays above 140F at low, the worst risk you'll have is overcooking. Beans and vegetables like carrots and celery can overcook fairly easily in a crock pot, but higher collagen meats meant for stews tend to be fine when cooked for extended periods. Most crock pot recipes for stews and soups usually hold fine when at low for a full workday, although that's presuming a somewhat 70s-era soup aesthetic, which is probable for a crockpot recipe.

However, I would be inclined to attempt the recipe using the low setting rather than reducing it to warm, if you're not going to test the temperature first. If it turns out to be overcooked, you can always puree the ingredients with a blender...

I also doubt that switching to "warm" would be dramatically less likely to overcook the food than "low", unless it holds at a pretty stable 140F, and low ends up somewhere around 160F.

Answer 2

will it be a bacteria minefield or will it be warm enough to keep the food safe from bacteria?

I can't really stress how important it is to have and use thermometers no matter your experience level. And especially if you are unsure if what you are cooking is safe. I prefer a non electric (less parts, requires no batteries, unlikely to break) meat thermometer.

Answer 3

will it be a bacteria minefield or will it be warm enough to keep the food safe from bacteria

The FSIS (food safety inspection service) has released time-temperature graphs. At 130F you not only deactivate bacteria like salmonella, you have a 7 log10 reduction in bacteria after 131 minutes (chicken), which is their "safe" limit.

They don't really advertise that you don't have to cook to 165F if you hold the temperature over a period of time. The USDA public temperatures are the instantaneous meat temperatures.

Answer 4

According to one of the Rival Crock-Pot manuals, it should not be left on all day. I have no intuition as to why though, other than they offer this advice so consumers don't expect it to bring all foods to a safe temperature.

HOW TO USE YOUR SLOW COOKER

1. Place the stoneware into the heating base, add your ingredients to the stoneware, and cover with the lid .
2. Plug in your Crock-Pot® slow cooker and select the temperature setting from the three setting options. Low is recommended for slow "all-day" cooking. One hour on High is equivalent to approximately 1½ to 2 hours on Low. Refer to your specific recipe for more precise cook times. Warm is ONLY for keeping already cooked food at the perfect serving temperature until you are ready to eat. DO NOT cook on the Warm setting. NOTE: We do not recommend using the Warm setting for more than 4 hours.
3. When cooking is done, unplug your slow cooker and allow it to cool before cleaning.

For more manuals (and recipes and such): Crock-Pot.com Customer Service