Food Preservation and Storage in the Desert

(Updated 1/22/2007)


When we moved to the desert in 1997, we decided to experiment with non-mechanical refrigeration. Purchasing an efficient refrigerator and the solar panels to power it would have cost more than our entire dwelling and would have introduced a mechanical noisemaker into our home. Instead, we decided to experiment with using the natural processes of the desert in various ways.

Food Cooling

During the winter months in the desert, keeping food cool is relatively simple since nighttime temperatures are commonly fairly cold. Food cooling is just a matter of putting an ice chest of food outdoors in a shaded location. Opening the lid each night allows the food to chill and closing it during the day keeps it cool.

Keeping food cool during the rest of the year, and especially in summer, is a significant challenge. We have experimented with a variety of substitutes for mechanical food refrigeration. Root cellars aren't particularly practical in this area since a depth of 10-15 feet would be required to encounter even minimally cool temperatures during summer.

Most of our early efforts revolved around evaporative cooling using damp cloth shrouds around food storage trays. Some of these methods were fairly sophisticated, incorporating float valves, water reservoirs, etc., all in an effort to modulate the quantity of water passing down the surface of the cloth. Enough water was needed to keep the cloth damp, but not so much as to waste water.

 

Above and at right: Two evaporative food cooler designs that have come and gone over the years.  The one above utilized a white cloth shroud around circular metal trays in which food was stored.  At right is a similar system that used fabric tubes in which  jars filled with food were stored.  

 

 

This approach commonly cooled food to about 30 degrees below the maximum ambient air temperature on hot days and, after some initial tinkering, worked satisfactorily...for awhile. Invariably though, after several weeks algae and mildew would begin to form on the cloth, gradually reducing its ability to wick moisture. The water depth in the reservoir would have to be readjusted more and more frequently until finally the cloth was unusable, usually within a few months.  This occurred with natural as well as synthetic cloth.

One summer morning, we noticed that water in a bowl which had been left outside overnight was unusually cool. The bowl of water happened to be stacked inside another bowl. Subsequent experiments confirmed my hypothesis about why the water was so cool. Water on the surface of the bowl was evaporating, causing the water to cool. At the same time, the stacked bowls were acting as insulation, preventing heat from entering the water around the sides and bottom. This discovery led to one of our current food cooling methods, which is quite simple.

We use an ice chest, not to hold ice, but as a water-tight container with insulated sides and bottom. It is filled with water and placed outdoors where it will be completely shaded throughout the day. The location is open to the nighttime sky, that is, not under a shade structure. The lid of the chest is left open at night and closed during the day. Food to be kept cool is placed in jars with water-tight lids and the jars are placed in the water filled ice chest. Jugs of drinking water are also kept in the chest.

 

 

Two simple evaporative food coolers

 

 

The cooling effect occurs just as it did in the bowl of water. Evaporation on the water surface cools the water and the insulated sides and bottom of the ice chest help prevent heat from entering the water. Since the ice chest is open to the nighttime sky, additional radiational cooling occurs. Water temperature is often as much as 35 degrees below maximum ambient air temperature. 65 degree F drinking water on a 100 degree F day may not sound cool to those accustomed to ice water, but is nonetheless remarkably refreshing.

We also continue to use a very simple version of the damp cloth shroud method for some foods. A pan is filled with a couple inches of water and placed in a shady location. Jars filled with food are placed in the pan and covered with a cloth which drapes down into the water. An old towel works well for this. The cloth wicks up water which evaporates, cooling the jars.

A tip when using evaporative coolers such as those described here is to use stored rainwater instead of tap water or well water. Rainwater is distilled and won't cause mineral deposits to develop on cloth or jars.

Food Drying

Drying is a natural method of food preservation here due to the heat and aridity of the desert. We have developed a simple food dryer that has proven to be both convenient and effective and, after many years of use, we cannot think of any improvements we'd like to make to it. Fruit, vegetables and meat usually dry within a day or two. The area under the dryer also makes a convenient place to store firewood.

The dryer consists of a couple of saw horses supporting sheets of corrugated metal roofing. Trays of 1/2" hardware cloth are placed atop the corrugated sheets. The trays are lined with insect screen and the food to be dried is placed in the trays. A large insect screen spread over the trays and clamped around the edges of the dryer prevents insects from contacting the food.

 

Drying table loaded with apples

 

Filled trays at one of our Food Drying Workshops

 

Canning

This is another method of food preservation that we frequently use. Since information on canning is easily obtained from other sources, we won't go into detail about it here. People not familiar with canning often express concern about spoilage in the desert heat. We've kept jars containing fruit, vegetables and meat for as long as 8 years in our outdoor pantry barrels. Rarely, a jar may come unsealed, but this is easily noted and the contents of the jar are discarded.

Food Storage

We made a weatherproof outdoor pantry from 55 gallon steel barrels.  It has served very well ever the years.

 

 

 

We cut the tops out of the barrels using a saber saw with a metal cutting blade. Donut-shaped shelves were then cut from a sheet of 1/2" plywood. The shelves are 1/4" or so smaller in diameter than the inside diameter of the barrels.

The shelves are fastened one above the other with three pieces of 1/2 " threaded rod that pass through holes drilled near the perimeter of each shelf. The shelves are secured to each rod with a nut and washer above and below each shelf.

 

Pantry shelf with threaded rod

 

 

We fashioned a lids from 2' square pieces of heavy sheet metal bent as shown below. Note the bead of caulk that acts as a drip edge, preventing rain from entering the barrels.

Two ropes over the lid prevent animals from accessing the barrel.


Pantry lid, showing drip edge

Pantry lid, showing hold-down ropes

 

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