If you need to keep items frozen then a high quality cooler and some ice packs can keep things cold for hours or even days at a time and stop them going bad.
But what if you need to keep something frozen and you don't have a cooler? How can you keep things frozen then?
The best way to keep things frozen without a cooler is to place them in a vacuum-insulated food canister or camp crock with ice packs. The vacuum insulation will stop heat getting in and items can stay frozen for hours. Alternatively, wrap frozen goods in aluminum foil and towels.
While it's more difficult to keep things frozen without a cooler it is in fact possible and there are a variety of techniques you can use to do so.
1. Use Vacuum Insulated Containers and Bottles
You might think that the foam in coolers is the best insulation for keeping things frozen but there's actually something better.
A vacuum is actually the best insulator for keeping items frozen and this makes vacuum insulated water bottles, food canisters and camp crocks (or thermal cookers) a great alternative to a cooler.
When I want to take ice blocks with me on a hike, to school pickup or climbing I'll often put them inside my Hydro Flask water bottle or for larger ice blocks or ice cream I'll put them inside my Stanley Camp Crock – which is like a giant vacuum insulated food canister.
Combine frozen food with ice packs and these can actually keep items completely frozen for 6+ hours with smaller canisters and 1-2 days with the larger camp crock.
Keep items hot for up to 12 hours and frozen cold for up to 16 hours. Features double wall vacuum insulation and a large 3-Quart capacity. Made from durable 18/8 stainless steel and has a leak proof locking lid and handle making it great for camping and travel.
2. Use High-Quality Ice Packs Designed To Stay Colder Than Ice
Ice packs are designed to stay colder than regular ice as it melts and this helps to keep items next to them completely frozen. Read about the science behind this.
Ideally you want to combine ice packs with some sort of insulation. If you don't have a cooler then a camp crock like we mentioned above could work otherwise wrapping your frozen food and ice packs in anything from towels, to blankets or sweaters will help to keep the heat out and keep things frozen longer.
The bigger the ice pack and the more insulation you wrap everything in the longer everything will stay cold. Check out my list of the best ice packs you can buy and choose on that suits you.
You can also make your own extra cold DIY ice packs at home with a water bottle, water and salt. The more salt you add the colder the ice pack is going to stay.
3. Use Aluminum Foil and Towel/Blankets
A quick and easy solution for keeping things cold for longer without a cooler is to wrap your frozen items in aluminum foil and then wrap that in some sort of towel or blanket like we mentioned above.
Aluminum foil is a good insulator against heat radiation and helps to trap in the cold. But aluminum foil by itself won't be enough.
Adding an extra layer of insulation using something like a tea towel, towel, blanket or sweater will help keep out more of the heat so things can stay frozen longer.
For best results place your frozen food items AND ice packs inside aluminum foil and then place all that inside a towel or blanket and keep out of direct sunlight.
4. Use Thermal Bags
Thermal bags use a similar insulating method to the aluminum foil + towel we mentioned above.
They have a foil lining to keep heat out as well as a layer of plastic or paper that helps to insulate your items further.
These are able to keep items frozen short term but they aren't the best option for keeping items frozen if you want them to stay frozen more than 3-4 hours.
You can put your frozen food inside a thermal bag and then combine with ice packs and wrap in a towel or blanket to keep it frozen for longer.
This thermal bag can keep items hot or cold for hours at a time and is 100% recyclable, food safe and reusable.
Lightweight, waterproof and easy to wash these can hold up to 30 lbs of weight before breaking and fold completely flat making them easy to store.
5. Use Dry Ice
Dry ice is frozen carbon dioxide and it has a temperature of -109.2ºF (-78.5ºC). It is so cold that anything it touches will also freeze, or stay frozen.
Dry ice can keep food frozen without a cooler for up to an entire day, if it's wrapped in a blanket or some sort of insulation.
Usually you'd want to place dry ice in a cooler to keep everything frozen but using the aluminum foil and towel/blanket method mentioned above will work great as well.
If you are keeping food frozen with dry ice you may want to separate the food from the dry ice by wrapping your food in a tea towel separately first and then placing the dry ice on the outside and wrapping everything in a blanket or larger towel.
This will stop the dry ice from causing freezer burn and ruining your food.
Always be careful when using dry ice as it can cause frostbite if it touches your skin directly and dry ice can be dangerous in confined spaces, so always make sure there is lots of ventilation.
6. Zip Lock Bags and Tissues
For keeping small items frozen for a short period of time without a cooler you can wrap the items in tissues or paper towels and then place in a ziplock bag.
For extra insulation you can added another layer of tissues and then place everything in a second ziplock bag.
7. Always Pre-Freeze Your Items
Whenever you're trying to keep something frozen you want to start with it as cold as possible.
You should always pre-freeze your items and never rely on your ice packs to freeze them, especially if you don't have a cooler.
It's also a good idea to turn down your freezer to it's lowest setting so that everything starts out as cold as possible. The colder it starts out the longer it'll take to thaw.
8. Use Ice Blocks and a Bucket
Did you know that you can use a 5-Gallon bucket as a cooler?
It's not going to keep things cold and frozen as long as a cooler would but if you place your frozen items in the bucket and surround it with ice or ice packs then you can keep the item frozen for a few hours.
You can even turn your 5-Gallon bucket into a cooler with some external insulating covers that go over the bucket. This will help everything stay cold for longer.
To keep thins frozen in your bucket even longer consider adding salt on top of the ice…
9. Put Salt Over The Ice
Place your frozen items in a container or bucket with a bunch of ice cubes and then cover the ice cubes with regular household salt.
The salt will lower the freezing point of the ice and cause it to melt. However, this process will also cause the ice to become much colder than it otherwise would be, and this can help items stay frozen for longer even when you don't have a cooler.
Salt is commonly used in ice to make ice cream. The ice cream churner is placed inside a bucket with regular ice surrounding it. Salt is then used to lower the temperature of the ice and this causes the ice cream to freeze as you churn it.
You can use the same strategy to keep your items frozen for longer and it's really simple to do.
10. Use a Dutch Oven and Towels
A Dutch oven is a cast iron pot and lid and can be used to keep things frozen without a cooler as the dutch oven will keep everything inside insulated.
To use this technique you want to place your dutch oven in the freezer with your frozen food and ice packs.
When it's time to go get the dutch oven out and line the inside with towels then place your frozen items and ice packs inside. Place more towels on top and then shut the lid to the dutch oven.
For best results wrap the entire dutch oven in a blanket.
The frozen cast iron will help keep everything cold longer and the blankets and towels will stop heat coming in and thawing everything.
While a cooler is still usually the best option for keeping thing frozen, and there are some great ways to keep things frozen in a cooler for longer, if you don't have a cooler you can still keep items frozen for hours or even days at a time.
The best way to keep items frozen without a cooler is to use a vacuum-insulated camp crock pot or food canister or to use dry ice. Placing ice packs next to your frozen goods and wrapping everything in towels or blankets are also a great way to keep things frozen for longer when you don't have access to a cooler.