Do you have to wait til food cools completely before refrigerating?
- The Oracle Jun 12, 2006 12:47 PM
Had dinner at a friend's house last night. When it was time to put the leftovers in the fridge, I was stopped. They told me that if you refrigerate food that's still a little bit hot, it will spoil more easily.
Is this true? I asked why and didn't get an answer, other than it'll spoil faster.
Is there something with the moisture collecting as it cools rapidly -- thus making it more prone to spoiling? Or is there some other secret reason my mother never taught me about refrigerating food!
I always figured that if food was lukewarm, it would be fine to put it in the fridge -- and that would be a far better alternative to it sitting out for an hour or two at room temperature.
(This was a regarding a pot of homemade beans, specifically -- but also rice and bbq'd meats)
The myth is not true except for baked goods and similar desserts or where the recipe specifically instructs.
So, your instinct is more correct. In fact, for certain things (like rice), it's very important that they not be left out too long (read up on bacillus cereus to learn more about how rice can lead to food poisoning that way...though most folks tend to wrongly attribute their food poisoning to other things.)
It is true that one tries to cool things like soups down somewhat, partly uncovered, before refrigerating. The rapid condensation of very hot vapors that would be caused by cooling covered and then in the frig tends to produce off flavors (often referred to as "sour" but not necessarily correctly).
That information your friend has is completely incorrect. Putting hot food in the fridge right away is the safest. Every minute the food sits cooling is more time for spoilage and contamination to occur. You want the moisture to stay in the food so keep it covered.
With old fashioned refridgerators it overtaxed them to put hot foods in the fridge. With todays fridges you can put hot foods in with no worries.
Here's info from USDA site
Should a large pot of soup sit on the range until it cools, or should it be refrigerated hot?
Hot food can be placed directly in the refrigerator or it can be rapidly chilled in an ice or cold water bath before refrigerating. Cover foods to retain moisture and prevent them from picking up odors from other foods.
A large pot of food like soup or stew should be divided into small portions and put in shallow containers before being refrigerated. A large cut of meat or whole poultry should be divided into smaller pieces and wrapped separately or placed in shallow containers before refrigerating.
(Source: Refrigeration and Food Safety)
Here's a quote from www.HomeFoodSafety.org
Holding Out on Hot Stuff
* Old Habit: When preparing a cooked dish that needs to chill (for storage or serving purposes), nearly four out of five home cooks think its necessary to wait until foods cool before putting them in the refrigerator.
* New Tradition: Once upon a time, placing hot foods in the refrigerator could lower the overall temperature of the fridge and cause foods to spoil. Not anymore! To ensure the freshness and safety of your freshly cooked foods, place them promptly in the refrigerator after cooking no need to wait.
whats "a little bit hot"? kinda a loaded question. As long as the product is out of "the danger zone" it's fine to let cool-until it gets there.
No way i'd be sticking 5 gals of beans in its pot straight from the stove into your average home cooler. You'd be surprised what hot foods can do to temps in a walkin-let alone your home reefer-ain't an old wives tale. Cool ship it and then reefer it okay.
As always heat quickly, cool quickly should be your guide.
ETA: just saw "lukewarm" chill it down.
As suggested below, unless you have a blaster fridge like restaurants, the best way to handle leftovers is to put them into a large shallow container (preferable metal or something else that conducts heat/cold well) and put that container in cold/ice water to cool as quickly as possible, and then into the fridge. If you put a deep pot of stew in the fridge or leave it out to cool off, it could take hours before the center is cooled out of the danger zone. Even restaurants with blaster fridges will transfer leftovers to swallow trays to cool quickly.
yes, the rule - at least of the public health department governing Seattle - is either ice bath with frequent stirring or 4" deep metal pans uncovered in refrigerator for thin soups, 2" deep for thick stews, refried beans, etc. Cool to 40 degrees w/in 4 hours, cover after cooling.
If your friends' supposition were true, I'd be dead many times over. :-) Put away some mac & ham & cheese in its casserole dish while still warm last night and had some for lunch today - and I'm still typing.
I do the same thing with chili, baked beans, meats, rice, veggies. Soup is about the only thing I'll cool a bit longer on the back of the stove or put into smaller containers so it cools more quickly.
I am concerned more about the food in the refer. What effect will the warm pot of food have on the goods that are already safe and cold? The answer is the heat in the warm pot will be transfered to the food that WAS cold before you put the warm pot next to them inside the refer.
I like to use the term "Heat Exchanger." To me everything in the Cosmos is a Heat Exchanger. Cold bodies sponge heat from Hot bodies. To keep all my leftover food safe I like the pre-chill method discussed by others below using a ice bath. Let the ice take the "Heat" (pun intended) from the Exchange with the pot of beans and not your milk that you put in the refer earlier to KEEP COLD.
I worked in a commercial kitchen once where I was told that you don't put hot foods in the fridge covered. On some occasions hot foods were put in partially covered to let steam escape, then covered when cool. I thought that the logic was that the condensation promotes bacterial growth. Now I'm a bit confused.
Wasn't there a Top Chef episode where multiple people had put the still-hot items into the fridge and the fridge was still warm the next morning? Obviously most people aren't going to put multiple huge hot items into the fridge at one time, but I still let food cool down a bit before putting it in just to keep the whole fridge from warming.
when it comes to cooked foods (like leftovers) there is no need to wait ( It's already cooked ) but when it come to freshly cooked food like sources and meats (meatballs or sausages) then you must wait. the cooling down is part of the cooking process.
Hmmm. When working in restaurants, the mantra was "the walk in is for keeping things cold, not for cooling them down," and I don't believe we ever poisoned anybody. There was some fear that putting a large container of hot food into the fridge created an "igloo" affect, where the center stayed hot and gave bacteria a chance to have a barn dance.
I recently happened upon this myth myself when someone told me something similar.
"They told me that if you refrigerate food that's still a little bit hot, it will spoil more easily."
I think the issue here is "it will spoil more easily" than what? It is in fact true that refrigerating a giant pot of beans that is still hot may result in spoilage. But putting it out on the counter to cool down first only makes it worse. If food is in the danger bacterial zone (about 45-140F) for more than 4 hours or so, you might get excessive bacterial growth. So, if you have a large pot of beans, chili, soup, etc., it may not cool down fast enough in the fridge. But cooling at room temperature will be even slower, so either use an ice bath to rapidly cool the large pot (stirring helps even more in the ice bath) or divide up into smaller containers that you spread out in the fridge (stacking them all together will create a similar problem to the large pot).
That covers one part of this myth. However, the other part postulates damage to items already in the fridge as the reason not to put hot foods there (as has been mentioned here). It makes sense -- you put a 150-degree pot of chili in a 40-degree fridge, and you might think the milk next to it might well heat up to 60... maybe 70 degrees?
Not really true, at least in modern refrigerators. In an old icebox, you'd just end up melting the ice block. In older refrigerators, you might challenge the compressor, or it might not respond fast enough. But modern fridges are generally meant to work hard and to circulate air well.
I did my own experiment after a friend repeated this myth to me. I took a 4-quart pot filled with simmering soup (which I didn't care much if it spoiled), covered it, and put it in the fridge. I put it on a middle shelf in the middle of the refrigerator. I didn't place anything directly on top of it, underneath it, or against it, making sure that air could circulate around the pot. But there was stuff less than 1/2 inch away from it on both sides. I used an IR thermometer to check the temperature in the fridge after a few minutes, and then every half hour or so.
Most of the food in the fridge only fluctuated by a degree or so. The food right next to the pot went up a maximum of 4-5 degrees early on, but since I keep my fridge at about 36 degrees normally, 41 degrees is still pretty darn safe, particularly just for an hour or so. And I don't have a special fridge -- it's about 10 years old and not anything fancy.
The soup itself did not fare as well. After about 90 minutes, its temp was still high in the middle, so I started stirring it every time I opened the fridge. It did manage to get down to the 40s, but it took about 5 hours total and was not ideal. I would usually use an ice bath in such circumstances.
Moral of the story? Generally put hot food directly into the fridge to get it to a safe temperature as quickly as possible. If you have something largish to cool, use an ice bath. Don't put it directly into the fridge. But definitely don't leave it out on the counter, where it WILL spoil. And if you do put hot food in the fridge, it probably won't spoil other things, unless it's REALLY big and you put stuff directly on top of it or something.
Setting up an ice bath for a large pot of food can be difficult, especially if your sink stopper doesn't achieve a complete seal. I put water 3/4 of the way up in a couple of Rubbermaid containers, and keep them in the freezer. One is pint-sized, the other a quart. Put the appropriate-sized one into the pot of food and set the pot on a metal cake rack. Between the ice in the center of the pot and the transfer of heat from the solid metal of the pot to the wire grid, the temp drops very quickly. I never put anything above lukewarm into the refrigerator.
I use 1 pint plastic cream bottles . Just be sure the bottles or containers are very clean before you fill and freeze. I store them in a big zip-loc in the freezer.
Another solution is to live in a cold climate, and utilize the great outdoors. Just be sure to use a non- animal accessible point in the great outdoors.
I cooled an 18 quarts of sloppy joes in two hours last week out on the deck, where the temp was 20 degrees F.. Split the batch- left 2/3 of it in the metal roaster pan, put the other third in a plastic tub, then stirred every 20 minutes or so.
Interestingly, the larger portion in the flatter metal pan cooled as quickly as the smaller portion in the more upright plastic tub.
<Interestingly, the larger portion in the flatter metal pan cooled as quickly as the smaller portion in the more upright plastic tub.>
That is no surprise, between the increased surface area of the roaster and the thermal conductivity of the metal, which quickly transferred the heat to the air.
I work for a company that demonstrates food in a store. I was trained that food must spend as little time as possible between 40 degrees and 140. That tells me food must be refrigerated as soon as possible to keep it from growing bacteria. Personally, I'm looking for a definitive answer, as well, because the person I live with freaks when I put things right in the fridge - my professional training is not believed.