A delicious dinner is made and there will be enough for lunch tomorrow. My wife will sometimes put the leftovers in a container and into the fridge as she is making our dinner plates. My thought is that the leftovers should be allowed to cool off first. Too much temperature difference going from oven to fridge, some weird chemical reaction in the food, it won’t taste as good tomorrow, something, something, I don’t know?
What about baking multiple chicken breasts (or whatever) for later in the week. Should they be frozen right away or allowed to cool some?
It isn’t about the leftovers in question, it’s about the other stuff in the freezer. Putting warm leftovers in the freezer can raise the temperature in the container “endangering” the other frozen stuff.
I think this is one of those things that is, maybe not QUITE an urban legend, but along those lines? Recently it came up in conversation that some folks were gently making fun of their grandmothers for believing that you had to let food cool a little before putting it in the fridge … and I was thinking “huh, I always feel like you have to let it cool a little, and I do that because my grandmother always insisted on the cool down.” As far as I know, food science these days says that sooner is better when it comes to refrigeration … maybe science worked differently back in my grandma’s day.
(I’m only being a little facetious, maybe there was some difference in the ability of an icebox to cool something down back in Ye Olden Days – maybe if it was already working hard trying to keep your other food cool, you were causing more problems then you were solving by putting a hot dish in there with the cool food?)
I was under the impression that putting hot food in the refrigerator increased the risk of botulism. However, the FDA site says that the real problem is leaving the leftovers out too long, rather than putting them in too quickly; also, it implies that most people think that the problem with putting warm/hot food in the refrigerator is, it overtaxes the refrigerator motor.
The magic numbers are 140 and 40. As in degrees. Between those temperatures, bacteria has a field day, so you are best off getting food into the fridge before it drops below 140, so that it can cool down rapidly. That doesn’t mean that you’re automatically going to poison yourself if something cools on the counter, but it doesn’t help, especially if you’re planning to eat whatever it is as a cold dish, rather than heated.
I often barbecue way too much meat on a weekend, and promptly refrigerate or freeze whatever we don’t eat. It has so far not damaged the freezer or refrigerator, nor has it poisoned anyone.
Basically, it boils down to what’s likely to be a good growth medium for bacteria. Meat, mayo, sauces, gravy, stuff like that? Refrigerate it.
We also often make bread. You bag THAT too soon, you’ll wind up with soggy bread, as the cooling bread inside the baggie condenses the moisture. But bread ain’t the bacterial culture that your chicken breasts are…
You can’t get botulism poisoning from food that has air surrounding it. Salmonella, yes. E Coli, perhaps, but that’s more a food prep issue. Botulism toxin only forms in anaerobic environments, such as home canned foods, when the internal temperature of the contents in the vessel (canning jar) are not heated high enough to kill off the botulism spores. The spores then produce the botulism toxin that is so dangerous to us.
You don’t need to worry about botulism from not putting your leftovers away correctly. But do worry about salmonella!
I think this is part of the answer. Certainly in the days when iceboxes were just that, putting a pan or container of hot food in would surely melt a lot of the ice. Once iceboxes became refrigerators, this became much less of a problem, but I’m sure the practice held over because that’s what everyone learned from their mother. Fast-forward 60-80 years and the practice still continues.
But, having said that, my wife has taken the food safety course twice, and she will wait until leftovers cool down some before putting them in the fridge so as a) to not risk warming up cold food in the fridge, and b) not overtax the fridge by making it cool down something that is still 180 degrees. But she doesn’t let stuff out on the counter for two hours until it’s room temp, either. We let stuff sit out until we are done with dinner and then put it away. Thirty minutes on the counter isn’t going to be a problem and by then it’s cool enough to handle and refrigerate.
If people are talking about a bit of leftovers, I don’t think it matters. But if you are talking about a big pot of soup or stock that you cook and then refrigerate to use later, you bet I’m not sticking containers of 210 degree soup in the fridge. I’ll let it cool down some.
…I would agree that putting food in the fridge may not be your best option if it’s 180-210 degrees. Then again, food that hot would take the skin off your mouth if you tried to eat it. As a rule, food THAT hot gets to SIT a while before anyone SERVES it, much less puts it away.
Never occurred to me that anyone would let food cool before putting it in an ICEBOX, but that makes sense, considering the hotter the inside of the box, the faster the ice would melt… but I’m not sure this has any kind of analog to modern refrigeration, unless you’re putting pots of boiling soup in there, or building fires in it, or something…
How much faster can a dish at well over 140 degrees cool, in a closed, filled refrigerator, than it does in the open in say a 70 degree room? There must be configurations in which the heat dissipation in the refrigerator is even worse (as well as more expensive).
When Mrs Gargoyle took a food handler’s course, it was recommended to let food cool down because otherwise excessive condensation droplets occur within whatever it is wrapped / sealed in, and it’s these droplets that create little germ-friendly pools for bacteria to frolic in.
I have no idea if it’s true however.
Overtaxing a refrigerator isn’t true though. The motor/condenser works equally hard regardless of the temperature. It is simply either on (while cooling the fridge to the set temp) or off (when cooled to temp).
Well, I came to say essentially this, but now I don’t have to type it all out.
I live alone, so if I cook something like soup, I will put into single-serving containers once it’s cooled a bit, then put it in the freezer.
Ditto for when I make a crock pot of something. I let it cool while I eat my first meal, then either put the entire pot in the fridge (to parcel out later), or I parcel it into containers and freeze them right away.
That said, I’ve occasionally put “hot” food into single-serve containers, then into the freezer. They’ve been fine and the ice cream hasn’t melted. Then again, no kids, so no one is compounding the temperature issue by opening the door to look for something to snack on.
It’s not about taxing the refrigerator so much as about heating up the rest of the stuff in the fridge.
I don’t know the math, but my second-largest stock pot full of pasta sauce will indeed melt the contents of all the jars and bottles on my top shelf that usually freeze because my refrigerator hates me. The items around the pot do heat up, probably above the bottom “safety zone”.
When it’s cold out, I cool things on the back (enclosed) porch before they go into the refrigerator. When it’s not cold out, I let them cool a bit on the stove, until they’re cool enough to put into ziplocks or small containers. Since a big batch usually means I’ve made several meals-worth ahead, some go into the fridge, some the top freezer and some the separate deep freeze. The larger surface area means they cool faster, and splitting them up means there’s not so much heat in any one cold space to warm everything up.
It’s not ideal, but until every kitchen comes with a blast chiller, it’s the best I can do.
I’ve always let food cool down before I refrigerate or freeze it. Usually way beyond the 40-140 degree rule. I usually wait until food gets to room temperature or so before I refrigerate/freeze it, and I’ve never had a problem. I learned from my grandmother, who does the same thing.
The food handling course I took recommended using an ice bath to cool soup pots more quickly. I.e., you fill up a larger pot with ice and put the soup pot in it. (They acknowledged that isn’t always practical, though.)
At home, where commercial size ice makers are rare, and one might be hesitant to completely empty the ice bin, an ice bath is overkill for this. I usually just fill the sink with cold water from the tap and plop the hot pot into that. If it’s a really big pot, I might need to change the water once, after it’s warmed some.
I really only do this for large amounts of soup or stock. For a huge pot of mostly liquid, even in the fridge it will spend more time in the danger zone for bacterial growth than if it’s been rapidly cooled in a bath. And as many mentioned above, I worry that a large massive heat source will raise the temp in the fridge, affecting everything else.
I think for many (most?) people, they’re only putting unexpected leftovers in the fridge and not a large pot of boiling soup. In which case you may as well get into the habit of putting it in after you’ve served up what you need, rather than allowing it to sit while you eat your dinner.
Then again, if you’ve cooked good food well enough there aren’t any bacteria in it, so just take care it doesn’t spoil by being left out too long.
On refreezing cooked chicken, the NHS says “It is possible to re-freeze cooked meat once, as long as it has been cooled before going into the freezer. If in doubt, don’t re-freeze. Frozen raw foods can be defrosted once and stored in the fridge for up to two days before they need to be cooked or thrown away.”
I have two methods: one, an ice pack, and, two a donated mini fridge that never has anything perishable in it. (It’s mostly for water, sodas, and such.)
Modernist Cuisine took IR thermal camera shots of hot food being put into cold fridges and showed significant warming of surrounding foods. If you don’t happen to have your $600 cookbook handy at the moment, there’s a single frame on their website along with the accompanying text: