Find two earthenware (clay) pots that have a slightly different diameter. Place the smaller pot inside the large one and make sure that there is a good amount of space (at least a couple of inches) between the two pots. Also check to see that there are no cracks or holes in either of the pots.
Gather some fine, wet river sand and fill the space between the two pots with the sand. Place enough sand in the space to fill it completely, but don't pack it down too hard.
Put your food or drinks inside the smaller pot. Make a note of the date that you placed the goods into your desert fridge. Then, cover the pots with a moist cloth or even a canvas tote bag.
Place your desert refrigerator in a cool, shaded and, most importantly, dry place to get it to work. Keep the sand between the pots moist by watering it every few hours with a small amount of water. Check the produce in the fridge every few days to see how it's doing and make notes about the amount of time that you can leave goods in the fridge before they spoil.
Experiment with your desert refrigerator by using different densities of sand, more or less water and different kinds of pots. Each time you change one of the variables of the refrigerator make a note of the date that you put produce into the fridge and how long they last so you eventually find the best configuration for the fridge.
