Anyone who has tried to store ice cream in a cooler only to get it out and find that's it's melted into mushy liquid knows that it can be hard to keep ice cream frozen in a cooler.
You can't just put ice cream in a cooler with regular ice and expect it to stay frozen. Ice cream is designed to have a melting point lower than that of water, so it will melt long before your ice does.
However, it is possible to do and in this article I'm going to show you exactly how to keep ice cream frozen in a cooler for hours or even days.
To keep ice cream frozen in a cooler your cooler must be colder than the freezing temperature 32 °F (0 °C). You can do this by using dry ice, adding salt to your ice which drops the temperature below freezing. You can also extend how long ice cream stays frozen by putting it in a vacuum insulated cup or by putting it at the bottom of your cooler.
I'll talk about each of these methods for keeping your ice cream frozen and explain how to best use them and why they work. But first let's look at why your ice cream doesn't stay frozen in your cooler even though it's full of ice.
Why Doesn't Ice Cream Stay Frozen in a Regular Cooler?
First I think it's important to understand why ice cream doesn't stay frozen in a regular cooler filled with ice.
Ice cream is designed to have a lower melting point than water. This is why when kept in a freezer at 0°F (-18°C) it is still smooth and easy to serve and eat and not completely rock hard frozen like ice is.
When you put ice cream in a cooler with regular ice then regular ice will keep it at a temperature below 32°F (0°C) but nowhere near the cold temperature of 0°F (-18°C) that ice cream is designed to be stored at.
This means that ice cream will quickly warm up and will quickly melt, well before the ice in the cooler even comes close to melting.
So just putting ice cream in a cooler with ice is NOT enough to keep it cold, so you need to use different strategies to lower the temperature of your cooler further so the ice cream stays frozen.
1. Use Dry Ice
The easiest way to keep ice cream frozen in a cooler is to use dry ice.
Dry ice is frozen carbon dioxide and it is much much colder than regular ice. Dry ice is -109.3°F (-78.5°C) which is even colder than your freezer at home. Definitely cold enough to keep your ice cream frozen.
In fact, dry ice is so cold that it can make your ice cream rock hard and unable to be served. So you need to take some extra steps to keep your ice cream frozen at just the right temperature.
Step 1: Cover The Dry Ice In Newspaper, Cardboard or a Towel
When handling dry ice make sure you use gloves or something protective and insulating as dry ice is so cold it can give you frostbite in just a couple of seconds.
Cover the dry ice in newspaper or a towel or put cardboard over your dry ice.
These materials are insulators and will protect your ice cream from the extreme cold power of the dry ice.
Step 2: Place Your Dry Ice At The Bottom Or Top Of Your Cooler
Depending on your strategy and how long you want the dry ice to last you can now place it at either the bottom or the top of your cooler.
Personally I like to place it on the bottom of my cooler, followed by a layer of cardboard or a towel. Then I put my ice cream in next so it's close to the dry ice and stays frozen.
On top of my ice cream I put frozen meats or other food I want to keep as cold and frozen as possible.
Lastly I'll put my drinks on top of all of this. This means the drinks are far enough away from the dry ice that they won't get completely frozen.
Alternatively, you can put your ice cream at the bottom of your cooler and put the dry ice on top.
Cold sinks so this provides more even cooling for your ice cream and this is effective if you have multiple buckets of ice cream that you want to keep frozen.
Step 3: Make Adjustments as Needed
You may need to make adjustments based on how frozen your ice cream is getting. Moving it closer to the dry ice if it's looking a bit melted or moving to further away from the dry ice if it is too hard and too frozen.
2. Add Salt To Your Ice
Adding salt to your ice is another way to lower the temperature of your cooler so you can keep your ice cream frozen.
This occurs because as the salt bonds with the ice it makes the ice melt. As ice melts it actually needs energy in order to turn from a solid to a liquid. It gets this energy by taking heat from the ice surrounding it.
So as the salt water ice melts it actually gets colder and this makes the cooler cold enough to keep ice cream frozen.
To do this:
Step 1: Put The Ice Cream Bucket In Freezer Bags
This method will cause ice to melt and will create a lot of water so before you begin wrap your ice cream buckets in plastic freezer bags so they are protected from the water.
Step 2: Put The Ice Cream At The Bottom Of The Cooler
Cold sinks and heat rises so to keep your ice cream frozen you'll want to put it at the bottom of your cooler as this will be the coldest area.
Step 3: Cover The Ice Cream With Ice
Now that your ice cream is in the cooler pour your loose ice cubes on top of the ice cream, making sure to have ice fully surrounding the ice cream container where possible.
Step 4: Pour Salt Over Your Ice
Now generously pour salt over the top of your ice. The more salt you use the faster the ice will melt and the colder your cooler can get.
Step 5: Close Your Cooler And Let It Do It's Thing
Now that you've poured salt over your ice the ice that bonds with the salt will start to melt and will make itself as well as the ice around it colder in the process.
This process can lower the temperature of your ice and the melted saltwater to as low as -5.8°F (-21°C) which is slightly lower than the temperature of your freezer at home.
Step 6: Add More Ice and Salt Where Required
If the cooler is not cold enough then you may need to add more ice or you may need to add more salt to speed up the melting process and to make the cooler as cold as you need.
3. Put Your Ice Cream In a Pre-Chilled Vacuum Cup/Container
This method can be used by itself to keep ice cream frozen for a couple of hours or it can be used in conjunction with the above methods to help keep your ice cream frozen for even longer in your cooler.
Vacuum cups like the Yeti Rambler Tumber 30 oz are larger enough to store a lot of ice cream. In fact the twitter post below shows that you can fit a small tub directly in a Yeti cup without even taking the ice cream out of the container.
Pre-Chill Your Cup For Best Results
For best result take the lid off your Yeti cup and put the cup in the freezer or fridge to cool down the stainless steel metal.
Alternatively if you don't have access to a freezer then put some ice inside the cup to cool down the inner walls of the cup.
This will minimize any heat transfer to the ice cream and help it stay frozen longer.
Put The Lid On
Put the lid of your cup on as these plastic lids will help keep out and and will do some insulating themselves.
Put Your Cup In Your Cooler
Now that your ice cream is in your cup place it in your cooler so it is exposed to less outside heat.
A vacuum is THE most effective insulator. So having a vacuum sealed cup insulating your ice cream inside a cold cooler helps it to stay frozen longer.
4. Use Ice From Your Freezer, Not A Gas Station
Buying ice from a gas station or super market is often referred to as “warm ice”. This means the ice does not start out as cold as ice from your own freezer at home and it melts faster.
This also means it's generally not cold enough to keep ice cream frozen.
Your freezer at home should be 0°F (-18°C) which means ice in your freezer will be the same temperature.
Use this ice on top of your ice cream and it will keep your ice cream around this 0°F (-18°C) temperature for a little while.
Over time the ice and the ice cream will warm up, but this will help you keep ice cream at least for a few hours if not 1-2 days depending on your cooler.
5. Mix a Small Amount Of Dry Ice Into Your Ice Cream
If your ice cream is already melted you can actually use dry ice directly in your ice cream to make it frozen. Break or blend the dry ice into tiny chunks or into a powder and then place this in your ice cream and mix it through.
The small part of dry ice will be cold enough to freeze your ice cream super quickly.
As long as the dry ice is food grade dry ice it is safe to consume.
The dry ice will simply sublimate (turn from a solid into a gas) and disappear. It may make your ice cream taste a little fizzy (like carbon dioxide in soda) but that can just add to it's interesting flavor.
It is very important however that you do NOT eat any chunks of dry ice. Make sure it has all sublimated into a gas before you eat your ice cream. Eating dry ice can burn your mouth and if swallowed dry ice can kill you…though this is extremely unlikely to happen as it would be too cold for you to swallow.
Other Tips To Keep Ice Cream Frozen In a Cooler
Here are some further useful time for keeping ice cream frozen in a cooler.
Put The Ice Cream At The Bottom Of Your Cooler With Ice On Top
Putting your ice cream at the bottom of the cooler with ice completely covering it is going to help it stay frozen for longer.
Cold air sinks so this ensures that your ice cream is in the coldest part of your cooler.
You also want the ice to completely cover the ice cream on top, underneath and on the side. This ensures the ice cream is getting cooled from all angles.
Open Your Cooler As Little As Possible
Once you put your ice cream in your cooler you want to open your cooler as little as possible until you need the ice cream.
Opening your cooler introduces outside air into the cooler. This outside air warms everything up and will cause your ice cream to melt faster.
So try to keep your cooler completely closed until you need to get your ice cream out.
If you have to use it then use it as little as possible and get everything quickly and then shut the lid tight so your ice cream and ice has the least exposure to the outside air.
Keep Your Cooler In A Cool Shady Spot
Keep your cooler in a cool shady spot out of direct sunlight. This stops a lot of outside heat getting into your cooler and also reduces the amount of radiant heat getting into your cooler.
Cover Your Ice Cream In Aluminium Foil
Aluminium foil is a great insulator of heat radiation. This is a type of heat that regular coolers don't really protect against.
Wrapping your ice cream buckets in aluminium foil will help to reflect this type of heat away from your ice cream while as the same time still allowing the cold temperatures of the dry ice/saltwater ice/regular ice to keep your ice cream cold.
Use a High-Quality Cooler
The better cooler you have the longer it can keep things cold. A Yeti cooler can keep things cold much better than a regular cooler.
A high-quality cooler with keep ice cream frozen much longer than a cheaper low quality cooler.