Ice-cubes are probably the easiest way to keep coolers cold. They are readily available at just about any convenience store or hotel lobby (for free) but they offer a challenge as they have a relatively high surface area to volume. This results in an increased melting rate when compared to say a block of ice with the same mass. We have all been there; we run to the closest gas station, grab a bag of cubed ice, toss it in the cooler, and before we know it our food is swimming in ice water. To combat this, we began storing our ice-cubes in plastic containers. We have found that an 8-quart plastic container will hold, roughly, five pounds of ice. The plastic containers keep the ice, and subsequent ice water, contained in one location and leaves your food dry. Keeping the melt water with the ice helps to insulate the ice and will actually help the ice last longer.
Solid blocks of ice are the best form to keep coolers cold; they have a lower surface area to volume than the same mass of cubed ice. The lower surface area reduces the melting rate and helps the ice last longer. Buying ice blocks at convenience stores can pose the same problems with water in the cooler as ice cubes. Containing this water is also important and why we recommend making your own blocks of ice at home. While many choose to use freeze water in used milk jugs; our favorite method uses the recycled Mylar bladders from Starbucks’ Coffee Travelers. These bladders can easily be removed from their cardboard covers, filled with water, formed to various shapes, and frozen. We recommend allowing at least 24 hours to for the ice to completely form. This is our preferred method for shorter trips; the downside to freezing your own ice blocks is the lack of being able to replenish the ice on longer trips.
Another great option for extending cooler life is freezing a portion of your food prior to the trip. We recommend this option for trips over five days, keeping at least two days’ worth of food thawed for use. Some of our river-rafting friends have even gone as far as freezing beer for multi-day trips. A few years ago we experimented with different canned beers to determine if this technique really worked. We tested four different beers against each other and against blocks of ice in 90°F outside temperatures. Our rather unscientific study showed a cooler filled with frozen beer stayed approximately 4°F cooler than an identical cooler with a block of ice. At the end of our experiment, all of the beer had thawed, while only 2/3 of the ice had thawed. Freezing beer does separate the water out of the beer solution and, when thawed, the produces ‘high octane beer’ and water mixture. If allowed to sit for a couple of days, the water will reincorporate back into the beer solution. We feel that given the effects freezing beer has on flavor, we would not readily recommend this technique for shorter camping trips. However, we think this technique does show some merit when it comes to extended travel, as this allows the alcohol in the beer to become reincorporated into the solution.
While coolers may not be the most ‘luxurious’ way to keep your food cold, we feel they are still a viable option for many camping trips. We continue to use coolers on many of our outings with great success. By combining these techniques, with a well-insulated cooler, we hope you are able to make the ice last a little longer on your next trip.
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