What's the scientific basis for this?

[Deleted User] · 16-06-2021 12:13am #1

I'm awake at ten past midnight, because I promised herself I'd wait for a lemon tart to cool, before throwing it into the fridge.

Why do baked goods need to cool at room temperature, before they can be sealed in the fridge, anyway? i've heard this 'rule' applied to everything from meat to baked desserts.

If I throw the tart in the fridge now (it's still a bit warm) will anyone even know? Will we die? I doubt we will die, but should probably check.

I suspect it's more to do with condensation than with food safety, is that correct?

Thanks

The chan chan man · 16-06-2021 12:15am

Throw it into the fridge and go to bed!

wonski · 16-06-2021 12:17am

Large amount of hot food can raise the temperature inside the fridge. We are talking large.

Other than that there is no risk and no one will die if you put it in the fridge

This is not food safety advice BTW.

Baked goods like cakes or tarts don't like sudden change of temperature and should always be let to cool down, though.

delly · 16-06-2021 12:21am

As above, it can alter the temperature in the fridge, but if covered it can also sweat. This would leave moisture on the top and affect the texture, basically making it a crap tart.

ED E · 16-06-2021 12:25am

delly wrote: »

As above, it can alter the temperature in the fridge, but if covered it can also sweat. This would leave moisture on the top and affect the texture, basically making it a crap tart.

This. If you put it in a container it'll really sweat.

Porklife · 16-06-2021 12:26am

wonski wrote: »

Large amount of hot food can raise the temperature inside the fridge. We are talking large.

Other than that there is no risk and no one will die if you put it in the fridge

This is not food safety advice BTW.

Baked goods like cakes or tarts don't like sudden change of temperature and should always be let to cool down, though.

Yep spot on.. slightly non sequitur but fat absorbs flavour and even more so if its warm.
For example, if you put a warm chocolate cake beside a pack of sausages, the cake will taste of raw sausage.
I learned this the hard way

Surreptitious · 16-06-2021 12:26am

If it's still hot or very warm it will sweat and unnecessary bacteria could form. That's why professionals use blast chillers which lower the temperature of food fast so it can be stored. At home you just have to let it cool.

[Deleted User] · 16-06-2021 12:28am

So I could just pop it in the fridge, but not seal the tupperware? That's ok right?

Cheers guys. Here's hoping for a non *gags* sweaty tart.

Porklife wrote: »

Yep spot on.. slightly non sequitur but fat absorbs flavour and even more so if its warm.
For example, if you put a warm chocolate cake beside a pack of sausages, the cake will taste of raw sausage.
I learned this the hard way

Noted. That sounds fcuking vile, tbf.

Tree · 16-06-2021 12:34am

As mentioned, you don't want to raise the temp of your fridge (not just food safety, the cooling motor don't like it), and you don't want the moisture to condense on to the cake.
Also, lemon tart should be fine on the counter overnight, (I assume it's one of those curd filled pastries), throw it in the fridge after you have a slice for breakfast

Potatopie · 16-06-2021 12:42am

The action of bringing food to the desired temperature in a controlled manner is called "tempering".
With your tart, as already mentioned, if you put it in the fridge hot or warm, the inevitable steam from the tart will hit a surface(probably the shelf above it) and turn into condensation and therefore drop back down onto your tart and leave residual water on top of your tart... Not very appealing and your lovely tart doesn't deserve that.
Also, as already mentioned, warm products going into the fridge can raise the temp inside the fridge. This really wouldn't cause much of an issue unless you put in a really hot, really huge something-or-other in there which raised the temp for a prolonged period of time. Your tart won't do that and therefore won't affect anything else in the fridge.
Still, it's better for the fats and proteins to cool down gently.
Enjoy! Sounds delicious!

[Deleted User] · 16-06-2021 1:20am

Tree wrote: »

Also, lemon tart should be fine on the counter overnight, (I assume it's one of those curd filled pastries), throw it in the fridge after you have a slice for breakfast

Just had a slice, that's called "payback".

Thanks for the info everyone. I guess the take-away is that it isn't dangerous, but desserts do need to cool down after all.

rubadub · 16-06-2021 4:27pm

I leave stuff out the back on a rack to cool quickly. If it was raining I fan it, or you might have an actual electric fan that can do it, many heaters are also fans but often full of dust and stuff.

jim o doom · 16-06-2021 4:33pm

I think the let it cool before putting it in the fridge is basically an old wives tale that's been perpatuated forever despite no actual evidence to support that it should be done.

If you leave something cooling, it is at a room temperature for a longer period of time where it is much more likely to develop harmful bacteria than it would if it was put directly into the fridge where it could cool quickly.

Had this argument with my wife previously, we looked online and could find no scientific basis for not putting food straight in the fridge, in fact all the information I found recommended putting the food directly in the fridge to prevent the devlopment of any harmful bacteria.

I watch a good bit of stuff on Bruno Albouze's cooking channel and he regularly puts items straight in the fridge or freezer to chill or freeze depending on what was needed for the recipe at hand, and he does a lot of fancy baked goods with high level chef skills.

rubadub · 16-06-2021 4:48pm

jim o doom wrote: »

I think the let it cool before putting it in the fridge is basically an old wives tale that's been perpatuated forever despite no actual evidence to support that it should be done.

Besides condensation issues I always heard it was since it can heat up stuff in the fridge which is more important to keep cold.

Like if you had raw chicken on a shelf above a massive pot of roasting hot stew it could heat it up and so the chicken could remains at say 20-30C for a long time.

jim o doom · 16-06-2021 4:55pm

rubadub wrote: »

Besides condensation issues I always heard it was since it can heat up stuff in the fridge which is more important to keep cold.

Like if you had raw chicken on a shelf above a massive pot of roasting hot stew it could heat it up and so the chicken could remains at say 20-30C for a long time.

I think the whole fridge heating up is a non issue - I've put half a large roast and other leftovers in my fridge still steaming hot after a big barbecue and there was no change in the internal temp of the fridge (it has a temp thing on the front).

As well as that, I've not seen any fridge instructions that recommend you not put hot food directly in for that reason, so I think it's pure old wives tales that get perpetuated as if it were common sense, but it actually isn't.

Surreptitious · 16-06-2021 5:00pm

jim o doom wrote: »

I think the whole fridge heating up is a non issue - I've put half a large roast and other leftovers in my fridge still steaming hot after a big barbecue and there was no change in the internal temp of the fridge (it has a temp thing on the front).

As well as that, I've not seen any fridge instructions that recommend you not put hot food directly in for that reason, so I think it's pure old wives tales that get perpetuated as if it were common sense, but it actually isn't.

You are wrong. Food has to be cooled down before putting it in the fridge. You are risking food poisoning. I was a chef for years and there's no way you should put hot steaming food into the fridge.

wonski · 16-06-2021 5:00pm

rubadub wrote: »

Besides condensation issues I always heard it was since it can heat up stuff in the fridge which is more important to keep cold.

Like if you had raw chicken on a shelf above a massive pot of roasting hot stew it could heat it up and so the chicken could remains at say 20-30C for a long time.

But raw meat should be kept on the shelf below

jim o doom · 16-06-2021 5:04pm

Surreptitious wrote: »

You are wrong. Food has to be cooled down before putting it in the fridge. You are risking food poisoning. I was a chef for years and there's no way you should put hot steaming food into the fridge.

If your common knowledge is a fact - provide some evidence.

NY times article stating hot food should go straight in the fridge: https://www.nytimes.com/2007/01/09/health/09real.html

Washington state department of health says its fine also and that its a myth that it has to cool first

https://www.doh.wa.gov/youandyourfamily/foodsafety/myths#:~:text=Myth%3A%20You%20shouldn't%20put,be%20placed%20in%20the%20refrigerator.&text=If%20you%20leave%20food%20out,for%20more%20than%202%20hours.

Also - Why exactly should you not do it?

10-10-20 · 16-06-2021 5:17pm

Part of this was more valid in the past when fridges had much more limited cooling abilities and didn't have fans to distribute the cold air around.
Back then your hot-tart/meat-joint could sit on a shelf and would cool down by losing heat to it's environment, but mainly it would allow heat to rise directly upwards and heat-up the contents of the shelf above. Depending on the enclosure or wrapping used, this would also create significant amounts of humidity which would rapidly condense and freeze on the cooling element, making the fridge even less well able to chill any products within. There was no self-defrosting technology back then!

With newer fridges which have air distribution and much better control systems, the issue is much less of a problem than it ever was.
But the good guidance still remains as not all fridges have fully functioning chilling systems and this would still be an issue with an overloaded/blocked fridge.

But in saying that, I still fire in a warm soup or roast and let the fridge just deal with it.

rubadub · 16-06-2021 5:21pm

jim o doom wrote: »

I think the whole fridge heating up is a non issue - I've put half a large roast and other leftovers in my fridge still steaming hot after a big barbecue and there was no change in the internal temp of the fridge (it has a temp thing on the front).

The temperature probe might be nowhere near the hot spot. Some idiot might have a bag of chicken fillets directly touching the side of a massive pot of stew in an aluminium pot readily transferring heat.

The thermometer could well be hidden behind a large mass of cold food and not get warmed up nearly as much as other spots. Also not all fridges will have the same cooling ability, or fancy fans etc.

https://www.fsai.ie/faqs/temperature_control.html

Q. How long can cooked food be kept at room temperature before refrigerating?

Following cooking, food which will not be consumed immediately should be cooled as quickly as possible and put in the fridge within 2 hours. Do not overload the fridge with warm food as this will raise the overall temperature of the fridge which increases the possibility of bacteria growing in the food.

Q. How can I cool down cooked food safely within 2 hours?

To speed up the cooling process for large quantities of hot food, you can use one or more of the following options:

Use a blast chiller to chill down food especially if you chill lots of food in your business. A blast chiller is specially designed to chill hot foods quickly and safely
Divide food into smaller portions. Smaller amounts of food cool down more quickly
Pour hot liquids or sauces into larger containers. The surface area will be increased and therefore the liquids will cool down more quickly
Place containers of hot food in cold water/ice bath. The cold water/ice bath makes the contents of the containers cool more quickly
While food is cooling down, stir regularly with a clean utensil. Stirring helps food cool more evenly
Move hot food to a colder area (e.g. a larder). Food will cool more quickly in a colder place
Some ovens have a ‘cool’ setting, which can help to cool down food by increasing the airflow around it (The oven should be cool first)

jim o doom · 16-06-2021 6:27pm

rubadub wrote: »

The temperature probe might be nowhere near the hot spot. Some idiot might have a bag of chicken fillets directly touching the side of a massive pot of stew in an aluminium pot readily transferring heat.

The thermometer could well be hidden behind a large mass of cold food and not get warmed up nearly as much as other spots. Also not all fridges will have the same cooling ability, or fancy fans etc.

https://www.fsai.ie/faqs/temperature_control.html

Yes, idiots do stupid things - however potential stupidity does not mean hot food shouldn't go in the fridge, once you're not an idiot and able to pay attention to what's already in your fridge, you should be fine.

From the link you posted the food "should be cooled as quickly as possible", and more importantly "Do not OVERLOAD the fridge with warm food".

Overloading (i.e. filling the food with a lot of hot food) is not the same as putting any hot food in the fridge at all. All the follow up suggestions are methods to cool it quickly.

Nowhere does it state to not put ANY hot food in your fridge, I've put plenty of half roasts that were still plenty hot, my fridge didn't cool down at all.

Also - the suggestions do not include "just leave it sitting at room temperature until it's cool enough for the fridge" - reason being, food at room temperature develops harmful bacteria faster than at any other temperature.

So the link does not support the argument "do not put hot food in the fridge", but it does support the argument "do not put lots of hot food in the fridge".

Gloomtastic! · 16-06-2021 6:54pm

Let’s try and keep it civil everyone. It looks like the food safety experts have changed their tune on this one so we’re all in uncharted waters.

The Gloomster!

jim o doom · 16-06-2021 7:49pm

Gloomtastic! wrote: »

Let’s try and keep it civil everyone. It looks like the food safety experts have changed their tune on this one so we’re all in uncharted waters.

The Gloomster!

Just for clarification, I wasn't calling the other poster an idiot -> I was saying that the person in their argument that who might put a hot item on top of raw chicken is the fictional idiot (in that example).

Only picking the argument apart, no insult was intended at all.

[Deleted User] · 17-06-2021 1:22am

Jesus, I opened some can of worms here:eek:

The tart was fine. Refrigeration caused no issues, but I would no longer place a hot dish in the fridge. Even after cooling, this tart seemed to "contract"? a bit; it was more dense than might be expected, like a dessert that had been refigerated for several days. Not ideal.

What's the scientific basis for this?

Comments