Preserving food after a power grid goes down (or other SHTF disaster that stops the flow of electricity) poses an obstacle, but not an insurmountable problem. Off-the-grid living options for food refrigeration do exist and can be accomplished in an economical DIY manner. Providing food security for your family should involve both growing/raising your own food and stockpiling long-term storage food. Crops can fail and livestock diseases spread quickly. Long-term storage food will remain shelf-stable for about 25 years and need no refrigeration.
An off-the-grid refrigerator, or zeer pot, is essentially an evaporative cooler that has been used in even the hottest climates for food preservation. For centuries, residents in the Middle East and even remote parts of Africa have used zeer pots to prevent food from spoiling. Building an old-fashioned ice house is yet another inexpensive way to keep the food you grow, raise and hunt from going bad. I toured several ice houses built by members of our local Amish community to learn the ins and outs of the process before building my own. While cutting and hauling ice slabs from a pond is the standard way the houses have been built for hundreds of years, it works equally well to fill 5-gallon buckets with water and allow the liquid to freeze before placing a lid on top. We plan on building both an off-grid refrigerator and an ice house; remember the prepping mantra, “two is one and one is none.”
Off-grid refrigerators of this type consist of two terra cotta pots. One pot is loosely nestled inside the other, with the opening between the two filled with wet sand. The sand creates a thermal mass barrier, which helps the inner pot stay cold once the “refrigerator” has been cooled down past room temperature. The thermal mass barrier also serves a wick that spreads moisture up and down the walls of the terra cotta pots. When the zeer pot is positioned in a breezy, shady spot, the evaporating water cools off the outer walls of the pots and chills the food placed inside. The pot will achieve even greater coolness when a solar fan is attached to the off-grid food preservation unit.
The temperature and air conditions on any given day do impact the ability of the zeer pot to keep food cold. If you live in a region where a fairly constant freeze and cool dry air is present, the off-grid refrigerator will keep fruits, vegetables, and many dairy products fresh and safe to eat for several weeks. Typically, a zeer pot inner temperature can cool down to approximately 40 degrees. A glass lid is placed on top of the zeer pot to prevent the cool air from escaping.
Although homemade zeer pots have been used for centuries, off-the-grid food preservation devices were introduced to the modern world during the early 2000s. Mohammed Bah Abba, a Nigerian teacher, sparked renewed interest in the pots after he began mass producing and distributing them to poor farmers in his country. Bah Abba was ultimately awarded the Rolex Award for his efforts to bring “life-changing technology to people in need.”
Off-Grid Refrigerator Supplies
- 18″ unglazed terra cotta pot
- 14″ terra cotta pot
- Refrigerator thermometer
- 7 terra cotta pot feet
- Sturdy planter caddy with five casters
- Silicone sealant
- 50 pounds of sand
- 4-inch long 1/2″ wide bolt
- 5 2-inch long washers for a 1/2″ bolt
- 4 jamb nuts for 1/2″ bolt
- 13 1/2 inch wide glass pot lid
- 12-inch wide sandwich basket
- 8-inch hook bolt or eyelet and a pair of nuts and washers
Zeer Pot Tips
- Unglazed pots work far better than glazed. The inner pot of the off-grid refrigerator does not have to be unglazed terra cotta, but the wick moisture effect will not work to cool the food properly if glazed pottery is used on the outer wall.
- Folks who live in hot and humid areas may experience a reduced cooling effect with their zeer pots. Less evaporation might occur, and the pot will not get (or stay) cool for an extended period of time.
- Zeer pots cool due to wind-induced evaporation. If the pot is placed in direct sunlight, the water will evaporate too quickly and cause the temperature inside the pot to rise and the food to spoil.
- The pot will get and stay cooler longer when two medium-sized pots are used. The proper surface-area-to-volume ratio must be maintained in order to garner the necessary temperature. When larger pots are used to store more food, the volume of the interior increases more rapidly than the surface area. Making additional smaller zeer pots in an effort to conserve money and still store more food will garner better results than investing in one set of large or extra-large pots.
Ice houses can be constructed from a variety of materials. The ice houses I toured, which were extremely chilly even on a hot, 95-degree day, were all made of a combination of metal, wood, and cinder block. Unlike the zeer pots, you can make the ice house as large as you want, but don’t bite off more than you can chew! The amount of ice needed to keep a 12X12 ice house cool year-round will require a significant amount of ice-hauling or bucket purchasing.
How to Build an Ice House
- Construct a building with a metal, wood, cinder block or concrete floor. A wood or metal shed can be retrofitted to become an ice house.
- Line the sides and ceiling of the ice house with Styrofoam panels for insulation. Thermal tech foil as used in the video above is also helpful, but using the foam panels and then adding a layer of the foil should yield even better results.
- If you are only storing ice for use inside a refrigerator or freezer, you will not need to add shelving to the storage unit. If the shed will be used to actually store food, place free-standing wood or metal shelving units inside so the food can sit on ice slabs or buckets placed upon the shelves. Do not screw holes into the building to hold the shelving units in place; cold air will escape through the holes and your ice will melt by late spring, if not sooner.
- Cover the floor with sawdust shavings or straw — or both.
- Place a row of ice slabs or 5-gallon buckets filled with cold water and a firm-fitting lid on a row of shelves, or put them on the floor if you’re not using shelves.
- Cover each row of ice or buckets with a layer or sawdust or straw.
- Place food on top of the ice slabs or buckets, if storing food, and repeats steps five and six until the ice house is full.
- The water from the buckets will ultimately melt. If you built a thoroughly insulated ice house and are lucky, the ice in the buckets will last until the following winter. The water can be boiled and used for other purposes. Clean the buckets before using them again if you are using the thawed ice as a backup potable water source.
Ice House Building Tips
It is often recommended that an average family should store between 500 to 700 cubic feet of ice (10 to 14 tons) per year. Storing approximately that much ice would require a structure with dimensions of about 12′ x 12′ x 8′ or 10′ x 14′ x 8′. You will need a sturdy ice saw, ice pick, and a strong back if harvesting your own ice from a pond.