Whether you’re camping or just going for a picnic, it’s always a good idea to take a cooler to ensure your food and drink is as fresh as it can be. Ice coolers are risky business, however, as ice melts at a seemingly random rate. Thankfully, there are ways to slow down the melting of ice when stored in a cooler, keeping your food and drinks colder for even longer.
Insulation is the act of trapping heat inside or outside of an object using insulative material. Most houses are insulated to ensure that they remain cool in the summer or warm in the winter. Insulation slows the heat transfer process, keeping the contents warm or cold despite the temperature on the outside. Reflective materials such as aluminum can keep the insides of the container cool as the heat is reflected from the outside.
How to Insulate a Cooler
The transfer of heat from outside of the cooler will inevitably lead to the contents of the cooler warming up. There are a couple of different ways in which a cooler can be insulated, to lengthen the lifespan of the ice inside.
- Wrapping your cooler in a blanket (especially a cold blanket!) can stop cold air from escaping whilst stopping warm air from reaching it.
- Whilst out and about, digging a hole to keep your cooler inside is also an option worth exploring. Being underground will keep it cooler for longer, due to the added insulation, but also because it’s generally cooler underground as the sun can’t penetrate it. Burying coolers (or any food) may not be the best method when in bear country, however, as it can easily be dug up.
- Thicken your cooler’s walls by using styrofoam. This can both reduce airflow but also trap the cold air which is already inside the cooler. While styrofoam is a good option, other types of foam work too, along with spray foam.
- Lining your cooler with aluminum foil can also do the trick, as it reduces the heat that can make its way into the cooler’s contents. The reflective elements of aluminum foil can keep the sun’s heat away from the cooler’s contents.
- Using a smaller cooler inside a larger one can also help, as the gaps between the smaller and larger one can be filled with ice bricks and other cooling substances to decrease airflow.
Different Types of Cooler
Of course, ice lasts longer in certain types of coolers than others. This can be due to the materials used in making the cooler, the insulation of the cooler and the density of the cooler. There are, thankfully, ways to help keep the ice in your cooler last longer regardless of the type of cooler it’s inside.
- Metal Coolers – Coolers made from metal are usually much heavier to carry, but are more robust than some other commercially available coolers. The most popular types of metals these coolers are made from are aluminum and stainless steel. Due to the material and density, the ice tends to last longer in metal coolers, but the outer casing is a double-edged sword as it can also heat up if left in the sun for prolonged periods.
- Plastic – Plastic coolers are also popular and are much more lightweight than metal ones. Plastic coolers also sometimes include amenities such as wheels and a handle which can be used to push it around like a trolley.
- Cotton – Cotton coolers are water resistant and are good for long trips as they’re less likely to be damaged by the condensation from the contents. They’re lightweight but due to their material, unlikely to include wheels.
- Canvas – Canvas bags are durable and easy to clean. Due to the material, however, they’re less likely to maintain a cool temperature in comparison to plastic and metal coolers. Both canvas and cotton coolers are better suited to short events, whilst plastic and metal coolers are more useful for longer events or trips.
How to Make Ice Last Longer
Making sure your items are already cool before being placed in the cooler is a tip that may be easily forgotten, especially in a rush. Keeping your drinks cold or even frozen before being packed away into a cooler can keep them even colder for longer, as the cooler won’t be needing to cool them down as much. The cooler itself can even be pre-cooled, by keeping it somewhere cold or filling it with ice, letting it cool, and then replacing the ice when the items are added to it.
Adding salt to ice is a method that dates back hundreds of years. This method was used when transporting meat even before refrigerators were invented. There are a couple of ways in which salt can be used to make your cooler even colder. These methods may not be advisable for use during long trips, but it is useful to know for trips where the cooler needs to be at a lower temperature than usual.
- Using a salt and water solution – Salt lowers the freezing temperature of water, meaning that once the ice melts (which it will do quickly as salt melts ice), it will be colder. However, if you want these effects to last longer, you can fill your cooler up with regular ice and include a couple bottles of frozen salt water, which will melt faster, thus maintaining the temperature of the regular ice for longer within the cooler.
- Adding salt to ice – Adding salt to ice will force it to melt faster, but did you know that ice is at its coldest when melting? By using regular ice in your cooler and adding some salt as it begins to melt, you can cool its contents a little bit more for a short period of time until the ice fully melts.
The best way of using salt in a cooler is if frozen saltwater is kept in a separate vessel away from the cooler ice.
The less space available for air to travel, the less heat transfer will occur inside your cooler. To keep your cooler cold by reducing the airflow, make sure that as much space is taken up within the cooler as possible. This can mean adding ice packs in between items, or cups, bottles, or cutlery that you plan on using. Packing extra ice in between items is, of course, the more ideal option as it means more ice for your cooler, but the other options work well as they limit the amount of heat transfer by blocking the flow of air around your cooler. This can, in turn, keep your ice cooler for longer.
How Long Does Ice Last in a Cooler?
Read more: How long does a cooler box stay cold?
How long ice lasts in a cooler depends on a lot of different variables. Things to take into account include the type of cooler, what conditions you’ll be staying in and what is contained within the cooler. On average, the ice in a cooler can last around two days providing steps are taken to prevent melting or to decrease the heat transfer within the cooler. Some coolers can last upwards of ten days providing conditions are perfect, but some claims can be outlandish.
Considering the insulation, air flow and contents of your cooler is the best way to increase longevity of the ice inside it.
What Should I Put in a Cooler?
When packing a cooler, it’s important to prioritize what needs to go in. Meats, cheese and other items of food which need to remain refrigerated would be needed to be kept in a cooler for safety purposes. If you aren’t carrying any food items that need to be kept refrigerated then you can pick and choose which ones you’d prefer to have chilled out of preference.
Bottled and canned drinks when chilled can keep the temperature of the cooler a lot more consistent, and can easily be taken out and replaced if something else needs to be chilled.
If you’re carrying a first aid kit, some pieces of first aid equipment may need to remain at a chilled temperature, such as cooling pads.
If you’re in bear country, your cooler should be at least 100ft away from your campsite at all times. Some bears are known to recognize coolers and understand that they contain food.
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