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Are Coolers Airtight?

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Any cheap cooler can promise to keep beverages frosty on a hot day, but deciding to purchase a quality cooler can become an expensive summer splurge. Some affordable coolers won’t necessarily have the airtight seal and insulation provided by premium heavy-duty coolers specifically created for long term cooling.

Most coolers are not completely airtight. However, the best coolers are designed to make sure it lets in as little air as possible. These premium coolers don’t come cheap due to the special manufacturing and insulation techniques, but they’re better at keeping your food and drinks cold longer.

The rest of this article will explain how a cooler’s quality depends on the manufacturing design, insulation, and proper ice packing technique to keep contents cold and mostly airtight.

The Cooler Manufacturing Process

Cheap coolers have thin walls, leaky seams, and uninsulated lids. On the other hand, premium coolers are created with rotational molding or roto-molding, a manufacturing technique that spins as the plastic is poured into the mold.

The plastic becomes more durable and uniform, which in turn is better at insulation due to its one-piece construction. While these coolers are more expensive than the average run-of-the-mill cooler, it is more effective at keeping air out.

Proper Airtight Sealing in Coolers

When choosing a cooler to purchase, make sure to check the seal around the lid of your cooler to ensure it lets in as little air as possible. Some coolers like this Stanley Adventure Heavy Duty Camping Cooler have additional silicone gaskets on the lid to ensure the lid is completely leak-proof and airtight while the lid latches are locked.

When ice inevitably melts in the cooler, the water level will increase. It is important not to constantly open the cooler to remove the water as the cool liquid is still insulating the cooler’s contents. Most coolers have a drain plug or spigot to drain the melted ice to avoid opening the lid. However, these plugs can be an additional way that warm air can sneak into your cooler. 

Quality coolers like this Yeti Tundra have a screw-in rubber gasket to keep the cooler airtight and leak-proof when the plug is closed.

Various Types of Insulation Used in Coolers

The effectiveness of your cooler not only depends on proper airtight sealing but also depends on the type of insulation used to manufacture the cooler. Most commercial coolers use foam between the inner and outer walls as insulation. 

Foam is filled with gas bubbles, and gas conducts heat less effectively than both liquids and solids. This prevents gas from transferring heat through convection, limiting the rate at which heat can be transferred from one molecule to another.

There are two types of insulation used in most coolers, which are closed-cell foam and open-cell foam. While open-cell foam is more flexible and light-weight, it also allows heat to travel through easily and is, therefore, less insulating than closed-cell foam. This foam is the type of insulation used in soft-sided lunch totes and coolers as it is portable and more comfortable to carry.

Closed-cell foam is heavier, denser, and more rigid. This foam is used with hard-sided coolers and is more effective at insulation than open-cell foam. It adds extra strength to the cooler and can make the cooler difficult to break. You will be better off with a closed-cell hard-sided cooler to keep your food and beverages chilled for a longer period than an open-cell soft-sided cooler.

Some cheap hard coolers can have little to no insulation on the lids or have thinner insulation on the cooler’s bottom that reduces your cooler’s effectiveness. This reduces the cooler’s ability to insulate as heat can easily enter through the lid. 

A cooler’s effectiveness depends on the type of foam, and the thickness of the foam used to insulate it. The thicker the foam, the more effective, the cooler will be. The combination of better insulation with thicker walls allows quality coolers to keep its contents cool for days.

In November 2019, cooler manufacturer YETI announced their YETI V Series Stainless Steel Hard Cooler featuring vacuum insulation rather than the usual foam type insulators. Vacuum insulation contains very few molecules. Therefore, it cannot transfer heat by conduction as it lacks molecules to bump into each other. According to YETI, this offers the very best thermal insulation that science allows. 

YETI V Series 55, Stainless Steel Vacuum Insulated Hard Cooler

While vacuum insulation has been used in drink bottles, it has never been used in coolers, as manufacturing is very costly. This cost directly translates to an expensive price tag for the consumer. However, this new type of insulation for a cooler pushes the bar on cooler manufacturing, and vacuum-insulated coolers are the very best money can buy at the moment.

Packing Your Cooler With Ice

Packing your cooler properly with ice can ensure that your contents remain cooler for even longer. Make sure to fill the cooler with ice and products completely to the top to avoid any excess air as air pockets can melt ice faster. As the melting rate of ice is related to its surface area, consider buying bigger ice blocks rather than using a bag of ice to keep contents for longer.

Advantages and Hazards of Using Dry Ice With an Airtight Cooler

Dry ice is also an option for keeping your food and drinks cold in the cooler. Dry ice is frozen carbon dioxide gas at a temperature of -109.3°F or -78.5° C and is colder than ice made from frozen water.

It is recommended to wrap the dry ice in layers of newspaper to avoid direct contact with food or beverages and place the block of dry ice on top of the cooler’s contents. Any space in the cooler should be filled with newspaper, dry ice pellets, or regular ice as dry ice turns into a gas rather than a liquid making it virtually mess-free.

This is called sublimation, the process of a solid going directly into a gaseous form, skipping the liquid state. The carbon dioxide gas from the dry ice needs room to expand and causes your airtight cooler to explode. Make sure to remove the plug from your cooler or purchase a dry ice compatible cooler like this ThermoSafe Dry Ice Storage Insulated Field Carrier.

ThermoSafe 390 Dry Ice Storage Insulated Field Carrier, polyethylene, 1 cu ft

It is important to wear gloves and long sleeves when handling dry ice, as improper usage can cause a painful injury similar to a burn. It is also important to keep in mind that carbon dioxide gas levels can rise to dangerous levels causing headaches, rapid breathing, and fainting.

Keep your cooler with dry ice separate in vehicles and tents, and make sure that all enclosed areas are vented as carbon dioxide can rise in an enclosed area or pool in lower areas.

Conclusion

Quality coolers are designed to be as airtight as possible to keep the warm air out and have thick insulation to ensure all contents stay cold. Most coolers are not totally airtight, and if you are using dry ice, a completely airtight cooler would not be the best option!

Buying the best airtight cooler with quality insulation won’t matter if you are constantly opening the cooler lid to reach for a drink. Every time you open your cooler, the contents come in contact with the warm air outside, making your ice melt faster and your drinks warmer. Don’t open your cooler too frequently, or consider buying separate coolers for food and drinks.