Most families can only watch as hundreds of dollars worth of food slowly spoils in their warming refrigerator when they watch disaster strike and the lights go out. What if you could make your very own cooling system using materials you most likely already have lying around your house?
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Check PriceThis isn't a new survival trick, it's an old technology that has kept food fresh for over 4,000 years even in the hottest places on Earth. It was used by the Egyptians, relied on by desert nomads, and is still considered vital information by modern day emergency preparedness professionals.
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Natural Refrigeration's Science
The secret is evaporative cooling. Think about how cold you feel when you get out of the pool on a windy day. That’s the same principle at work. Water evaporates and heat is pulled away from the heat surrounding it. This can create a temperature drop of 20-30 degrees compared to the outside air.
Your homemade cooling system achieves this by establishing a regulated setting where evaporation consistently occurs around the area where your food is stored. The essential component is the optimal combination of humidity, air circulation, and insulation.
How to Build An Emergency Cooling System
You will need two containers. The first is a smaller pot that will fit within a larger pot with at least two inches of space all around. The best materials are terra cotta or unglazed ceramic since they will let water seep through slowly. Metal containers will work in a pinch.
Use wet sand, sawdust, or even wet towels to fill the gap between the boxes. The filling should be wet, but not with an excess amount of water. If you add too much liquid, it will create mud that will be too dense to breathe, and too little will not be able to sustain the evaporation cycle.
Different climates will determine your pace on how often to re-wet the cover, however it is recommended to do this every 12-24 hours. As the cover acts as a wick, it will pull moisture up from the sand. More evaporation surface area is created by the additional cloth, so it is better to have a cloth that covers the entire system and hangs over the edges.
Maximizing Your Cooling Power
Where you put this system affects its efficiency a lot. Look for the spot that has the most shade and wind. If possible, try to find a shaded area that has breezes cross it like a covered porch, but if you can't find that just put it under a tree. Any shade is better than being in the sun.
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The size of your sand gap plays a role in the capacity of your unit cooling. Evaporation will be more efficient with wider gaps, however, they will need more water and require more maintenance. Most families fin that 2-3 inches of wet material around all sides helps to achieve the best balance of cooling effect and water saving.
Temperature drops depend on the humidity levels in your area. If you live in a dry climate, you can achieve internal temperatures 30-40 degrees lower than the outside air. If you live in a more humid climate, you can expect internal temperatures to be more modest drops of 15-20 degrees lower, which is still low enough to significantly slow spoilage.
What Foods Work Best
This system is designed specifically to keep food fresh without needing to freeze it. Your food will stay fresh 3-5 times longer than if it was just left out. Cheese, root vegetables, and certain types of meat will last the absolute longest.
Do not store food that is wet or leaking, as this can contaminate the sand layer. All food should be stored in sealed containers or wrapping. This will help to reduce moisture transfer and pest issues. Great options include glass jars, plastic containers, and clean cloth wraps.
Some of the fresh vegetables can last longer in this system than they can in modern refrigerators. This is because consistent humidity prevents wilting and the cool temperature slows decay.
How to Troubleshoot Issues
If your system isn't cooling properly, first, check for these common problems. Dry sand indicates a lack of moisture. If the sand is soggy and muddy, you may be overwatering, which prevents airflow. Both of these issues stop the evaporation process.
If your system has developed high internal temperatures, it may be due to poor placement. Your system’s cooling capacity can be easily overwhelmed due to direct sunlight, stagnant air, or nearby heat sources. Simply relocating the system even a few feet may increase its effectiveness by a factor of two!
Cracks and chips in your containers let air in and disrupt the controlled environment of the container. For small cracks, seal them with food-safe materials. If the container is more seriously damaged, replace it.
Advanced Cooling Techniques
After you have mastered the basic system, the following upgrades will provide even better performance. Partially bury the entire setup. Soil temperatures remain cooler and more stable than air temperatures. With just 12 inches of earth contact, cooling can be improved by 10-15 degrees.
Due to the fact that they are easier to maintain, and to replace if something goes wrong, multiple smaller cooling systems usually perform better than one large unit, Many smaller units should be built and they should be separated by food types, one for dairy, one for vegetables, and one for leftovers.
Adding a basic thermometer will help you monitor the internal temperature of the system so you can track its performance in varying weather conditions. This information assists you in determining how long food will remain unspoiled so you can better plan food usage.
The simplicity and effectiveness of this old technology speaks for itself. It uses no moving parts, electrical components, or maintenance, just the physics that have been working the same for thousands of years. This wisdom, when combined with contemporary technology, can determine if food, can be stored or not.
