How to Keep Your Cooler Colder, Longer
No, the answer is not just keep adding more ice. Well, ok maybe that is a solution but let”s say for arguments sake that you are interested in filling up your ice chest up once at home and then having it stay cold for the duration of your week-long trip with no additional ice available. Now we have a challenge.
The basics of using an ice chest are straight forward; put your food in it, add ice, and head out. Your food will stay cold for some period of time based on the efficiency of the cooler, the temperature of the area you are staying, and the amount of ice you use. The longer you plan to stay out, the more ice you will need.
But this is really an over-simplification of the steps you can take if you want your cooler to stay colder longer. There are several additional things that you can do to greatly extend your cooler’s chill. Of all these things, the most significant and recent game changer has been the ability to start with one of the high performance coolers made today. While these ice chests are not a requirement to meet our week-long goal, the high performance coolers that have been developed over the last decade have greatly extended the user’s capabilities. Modern premium brand ice chests are redefining our expectations of how long a cooler should stay cold. Unfortunately they are also redefining how much a cooler can cost.
One way to to keep an ice chest cold is to just add new ice each day. If you have access to daily ice and you prefer this method, you are all set. In this article I am going to tell you how to prep and pack your ice chest so that you can expect all of your food to stay cold for 5 days without having to add any additional ice regardless if you have a high-performance cooler or not. Many ice chests will claim that they can stay cold for a week or longer right on the label. This is usually an over-exaggeration compared to real world performance. Follow the steps below and you will make their performance claim a reality.
Lets get started.
Consumer Grade or High Performance Ice Chest
Consumer Grade Ice Chest
Coolers of years past were relatively simple in their design and concept. Start with an exterior shell of thin sheet metal or hard plastic, insert an insulating layer (1 – 2 inches thick) of closed-cell foam (think packing material that comes around new TVs), and then press in an internal plastic liner. What you ended up with was basically an insulated box that would reasonably try to keep the cold in and the hot out. While design and manufacturing processes have evolved over the decades, these modern consumer grade coolers have not strayed far from their original design parameters or their early capabilities. These coolers are effective, available in a wide variety of sizes, and most notably, affordable. They are still widely available today from many well known manufacturers and they are the standard cooler used by most people.
The Modern Ice Chest
A “Yeti” was once thought to be “a large hairy creature resembling a human or bear”, or in my case, I picture my 9th grade biology teacher. Today the name is more commonly associated with a premium brand of ice chest that utilizes highly engineered construction and insulating technologies to produce some of the highest performing ice chests on the market. These coolers also cost as much as three times that of similarly sized consumer grade coolers.
There are several other brands beside Yeti (Pelican comes to mind) that are competing in this ultra-performance level of cooler market, each with their own design philosophy and priorities, and all expensive. This means that the purchase of these ice chests will be limited mostly to those people either demanding the highest performance and greatest durability or, enthusiasts who are interested in exploring the extreme capabilities of modern technology.
These coolers do live up to their names, however, and are dramatically changing the expectations on how long a cooler can keep its chill. But even with the recent advancements in insulating technologies, the traditional methods of keeping your food cold are still the standard practices no matter which cooler you use and will only be magnified when used in conjunction with one of these modern premium ice boxes.
Pick the Correct Size Ice Chest
Start with the right size. Picking the right size ice chest (aka cooler) is key to having a chance at keeping your stuff cold, especially for long periods of time. Not only do you need enough space in the cooler for all of your food, but you shouldn’t underestimate the space you’ll need for all of the ice. When I look at the internal dimensions of an ice chest, I usually visualize somewhere between 1/4 to 1/3 of the space filled with blocks of ice. If I’m forced to use cubes, I save half of the space for ice. Then I visualize the remaining space and decide if I think there is enough room for the food I want to pack. If the answer is “no”, then it’s time to find a bigger cooler. If I am trying to keep cans or other drinks cold, I bump that estimation up to 50/50 at a minimum and I greatly reduce my expectations. Keeping drinks ice cold for a week, without freezing them and without adding ice, is probably the hardest thing you can try to accomplish unless you are camping at the South Pole. This is where the Yetis really come into their wheelhouse.
If you do not already have an ice chest or are considering buying a new one, keep reading this section to get some additional information on sizing and some examples of what has worked for me in different situations. If you already have a cooler, skip down to the Pre-Chill section and we will start talking about what to do to keep your cooler colder longer.
How Coolers are Sized
A cooler’s size is determined by the volume of the space it has on the inside (usually measured in liters or quarts), not how big it is on the outside. This can be deceiving sometimes because the external dimensions of two coolers can be roughly the same while the internal volumes can be very different. This is due mostly to the different thicknesses of insulations used by manufactures to reduce what is called thermal flux, basically how much the cooler resists letting the cold out. It is the internal dimensions that we are most interested in because that is the space that we will actually be using for our food and drinks. However we can not completely dismiss the importance of the external dimensions because we still have to be able to store, carry, and load the cooler in our vehicle when we travel.
When thinking about cooler sizes, there is no regulating agency that has determined what what we call each size. For discussion purposes, I will describe coolers as small, medium, large, and extra large but remember it is really the liter displacement that we are talking about. Fortunately almost all coolers have their displacement (size) number built right into their model names so we don’t have to go looking for them.
Here are some general examples of cooler sizes and what they work well for:
- Small 5 – 20 Quarts Solo / Day Use
- Medium. 35 – 55 Quarts Couple or Family Weekend
- Large 65 – 95 Quarts 4-5 Day Trips
- Extra Large 110+ Quarts. Week Long Trip / The Super Bowl
I like it when I can buy one item of a particular piece of equipment and have it work for all occasions. It means I have to spend less money and I have to store less crap. Unfortunately ice chests do not cooperate well with that philosophy. Sometimes I am going out solo for a night and only want to take a few cold luxuries and other times I need to feed the entire family for a week and the cooler has to hold Costco-size packs of everything. Thus, I currently use 2 different sizes of cooler for the family trips and I have a couple random individual-size coolers that have just shown up over the years that I use for day trips.
My Medium Size Cooler
While I would love to be out for a week or more every month touring our national parks and getting away from the daily grind back home, this is not the reality. Probably just like you, I still have a day job to perform and the kids have a dozen activities each week that we hate to have them miss. So the most common family camping trips we go on are for two-or-three-day weekends at one of our local campgrounds. In Southern California this means that with our mild weather and some simple planning, we can almost always pack all of the food we want to bring in what I call the “medium” ice chest and do just fine.
I use an Igloo Glacier Marine 48 Qt. / 45 Liter Ice chest that we got from Costco during one of their summer sales. It is a very simple and basic ice chest with no frills. The insulation is only about an inch thick and the body, while steady, will not repel the advancements of a hungry bear or an aggressive raccoon. This cooler does however have enough space to hold our desired food and sufficient ice for a mild-weathered weekend at one of our local campgrounds.
My Extra Large Cooler
The second cooler we have is our “extra large” ice chest. It is an Igloo Glide PRO 110 and it holds 110 quarts. It has wheels and an extending handle to help muscle it around when it is full. The insulation is approximately double that of our medium cooler at two inches and the lid has latches that help hold a tighter seal around the lid. This cooler, when using dry ice and regular ice blocks together, has kept food cold for five days in consistent 100+ degree days in Zion National Park. This is also the cooler that we most commonly deploy when we are hosting a backyard BBQ or a family gathering.
Pre-Chill the Food and Drinks
Making sure that everything that goes into the cooler is already cold is key. It takes a lot more energy to cool things (especially water) than it does to keep them cool. This is especially true for any cans or drinks you bring because liquids need the most ice to chill and keep cold. If you do not pre-chill, and in some cases pre-freeze some items in your cooler, then as soon as you add your ice, you are using a huge amount of your ice’s “coldness” just to cool your stuff down. This will eat up your ice pretty fast and it will likely not last for the duration of your trip.
Freeze the Water
Freezing some water was a trick that I figured out one time when I was packing a cooler for a short trip and I didn’t have access to 25 lb blocks of ice (my preferred cooling source). I took 2 empty 1 gallon milk jugs, filled them with water, and froze them. When they were ready, I had two 8lb. blocks of ice which worked really well in my medium size cooler. I found that not only were they easy to move around because of the handles, but also because they were in jugs, when the ice melted the water did not pool around the bottom of the chest! I also found that after the ice melted, I had two additional gallons of drinking water available beyond what I had planned to bring (packing a little extra water is never a bad idea).
Ditch the Ice Cubes, Use Blocks
One characteristic of ice is that the smaller the pieces, the faster heat will transfer, and the faster the ice will melt. This is why if you dump an entire bag of ice cubes on some drinks, they will get cold in about 30 minutes. This is also why all of the ice will be melted by the end of the night.
The key to getting your ice to last is to not use it any faster than necessary. In practical terms, this means using large blocks that have a relatively smaller surface area and thus will cool things around them more slowly, but ultimately last much longer. Blocks are also much more space efficient because you do not waste all the void spaces between the cubes wasted and therefore you get more ice in a given area. Large ice blocks are also usually cheaper pound for pound.
My favorite method has always been to use 25 lb. blocks of ice I used to get from the local fishing docks (long range fishermen used to use these blocks to keep their catch cold before onboard boat refrigeration). These ice blocks are about 10 inches square and are easy to pack around in large coolers. Being the largest practical size of ice available, they also last the longest. 25 lb. blocks of ice however have become harder to come by over the years and in some areas may not be available at all. In this case you will want to look around your area and see what other options for block ice are available. I have noticed in our local Smart & Final stores that they have 8 or 10lb. blocks available as well as dry ice.
“Blue Ice”
So here is science’s solution to keeping things cold. Blue ice is a chemical contained within a plastic shell or bag that has a greater specific heat and greater latent heat of transformation than water. Oh wow, lets get away from the chemistry jargon. What this means is blue ice is a man made chemical that “holds more cold” than a piece of ice the same size would. The idea is that blue ice will stay colder, longer, than ice will. It also has the benefit of not melting and getting all of your stuff wet.
Blue ice use to come in only small pieces making it only suitable for small personal use coolers. Recent advancements in the product are now offering significantly bigger pieces that are sometimes “custom fit” for a specific brand of cooler. These plates of ice can be very effective at keeping things cold for a day or two however their overall volume is still usually much less than using large blocks of ice and are less effective over multiple days. Blue ice is also more expensive then regular ice and you have to store it when you’re done using it.
I will use blue ice in my personal sized cooler for a lunch or day activity but otherwise I usually choose not to use it. It is an option however you can consider based on your needs.
Dry Ice
Dry ice is where we kick it up a notch. Using dry ice can greatly extend your camping session but it also has its challenges to work with. If you do not pay attention to it, it can cause more harm than good so take the time to familiarize yourself with it before you go out. Also remember that while dry ice is not toxic or poisonous, it can easily cause skin damage and injury if inappropriately handled. Never touch it with bare hands or place it in a sealed container that cannot naturally relieve built up pressure.
My general thought on dry ice are that if I am going to be out for three days or less, it is not worth working with and I will stick with standard ice. Once my trips go between four days to a week, dry ice is my go-to solution to keeping things cold.
While standard ice might be as cold as 6° F (a common freezer settings), dry ice has a surface temperature of -109° F! This means that a relatively smaller piece of dry ice has the cooling power of a much bigger block of regular ice. Additionally, dry ice does not melt, it sublimates, which means that it transitions directly from a solid to a gas as it warms up. This is important for two reasons. One is that you will not have to worry about generating additional water in the bottom of your cooler that the regular ice will then have to keep cold. The second reason is that as the dry ice transitions from a solid to a gas, the gas that is given off is still very very cold and will fill in all throughout the bottom of your cooler. This gas (non toxic carbon dioxide) is plenty cold enough to freeze any water it comes in contact with as well as any food. This is why using dry ice can greatly extend your coolers ability to stay cold but also why it is important to use it correctly. Otherwise you may just end up with one solid block of frozen stuff in your cooler and much of your food could be ruined.
The trick to using dry ice is to not go overboard and use too much. You need to also properly insulate the dry ice itself so that it does not touch or over-freeze any of your food. The idea here is that we want the dry ice to slowly keep our regular ice cold and so that it does not melt which will then keep the food cold.
The best method I have found for using dry ice is to buy a 10 lb. block and to wrap it up in a paper grocery bag. The paper bag serves as an insulating layer, slowing the conversion of the solid ice into gas. Then I place it at one end of the cooler and then place my ice block(s) or frozen milk jugs (full of water) against it, holding it to the cooler wall. I then place all of my food and drinks on the other side of the ice, using the ice blocks as a buffer. I also usually place my frozen foods closer to the dry ice and the non-frozen foods farther away. Inevitably, some of the dry ice gas will pool around the bottom of the cooler and some spots of frost will show up here and there so be mindful of what you put near the bottom. Tubes of mustard and other condiments that are not as sensitive to freezing and thawing go well here. You can also try to contain all of your food in a small box or plastic container to isolate it further from the freezing gas although I do not usually take it this far.
Pack with a Plan
If you are pretty organized with your meal planning there is another opportunity to extend the chill of your cooler. Foods like bacon or tubes of sausage can easily be frozen (without ruining the food) with the anticipation of consuming them later in your trip. Not only will this keep the food from perishing longer but it will also add another cooling item to the cooler. Also consider foods that do not spoil as easily or do not have to be kept as cold. Put these things in your meal plan later in the trip and pack them deeper in the cooler. Then plan to eat your most perishable foods (like fresh fish filets, etc.) in the first couple of days.
Limit the Opening
Now that we have added just about all the “cold” we can, lets take a look at our setup to see what can be done from a management point of view. One of the last things you can do to keep your stuff cold a little longer is to limit unneeded opening of the cooler. Every time you open the lid, a little more cold air gets pushed out and the ice has to work to cool it down again. So while you shouldn’t hesitate to get something you need, you can extend your cooler’s chill by not leaving the lid open unnecessarily.
Place in the Coolest Spot
Once you have followed all the steps outlined above it is time to head out. One of the last things you can do to extend the life of your cooler once you get to your destination is to keep it in the coolest area possible and out of direct sunlight. This usually means not leaving it in the back of your SUV or Truck, but it might if that is the coolest area.. I usually prefer to keep the cooler under the most shaded end of the picnic table as that is where most of the eating and drinking takes place. Then I set up my stove and the other camp kitchen items around it and access becomes very convenient.
I hope some of tips above will help you in your camping planning and help keep your cooler colder, longer. If you have any questions or other ideas you would like to share, please leave then in the comments section. I would love to hear about any other tricks you have tried out.