I hope you have plenty of non-perishable food stored for a potential power outage, but that does not necessarily mean you have to throw out your refrigerated items right away. Using two terracotta pots, sand, water and a cotton cloth or towel, you can make an evaporative refrigeration system called a zeer pot. Ancient people used evaporative cooling techniques from 2500 B.C. However, developmeny credit goes to Mohammed Bah Abba, a teacher in Nigeria in the 1990s, who made the zeer pot system we demonstrate here. He calls it the Pot-in-Pot Preservation Cooling System. In rural Africa, the zeer pot has allowed farmers to increase profits by keeping fruits and vegetables fresher from 2 to 20 days, cut down food-borne illness and store vaccines and medicines that previously could not be kept.
The pot-in-pot system works by evaporation. As the water in the sand evaporates, it takes heat from the internal, smaller pot, cooling down its contents.
What You Need
- Two unglazed, porous clay pots—one larger and one smaller (make sure the smaller one fits inside the larger one without touching)
- Bag of sand
- Cotton cloth, sheet or towel large enough to cover your largest pot without gaps
- Putty, duct tape or other sealant
How to Make the Zeer Pot
- Seal any cracks or holes in both pots with putty, duct tap or other sealant. You need to cover the holes in the bottom of both pots so no water or sand leaks out.
- Place sand in the bottom of the larger pot, but do not fill the pot. You want just enough height at the bottom so the smaller pot’s rim is flush with the larger pot’s rim.
- Place the smaller pot in the middle of the larger pot. Add or remove sand until both rims reach the same height and are level with each other.
- Slowly fill the gap between both pots with the remaining sand. You want the sand to reach the top of the pots.
- Pour water slowly and consistently into the sand. Distribute the water evenly. Put enough water for all the sand to be wet. However, do not flood the pot. You do not want standing water on top of the sand.
- Put your fruit, veggies, cheese or drinks inside the smaller pot. If you want, you may put a lid over the smaller pot.
- Dampen your sheet, cloth or towel with water.
- Cover both pots with the dampen cloth.
- Place your Zeer pot in an area with low humidity with plenty of air circulation.
- To keep the insides cool, add water to the sand about twice a day.
Because of the porous material of the pots, contaminated water may contaminate your food. It is safe to use non-potable water. However, if you use questionable water, put your produce inside a plastic bag first before placing it into the smaller pot.
Zeer pots work most efficiently in dry, arid climates with low humidity and plenty of air circulation. In the dog days of summer, when it is extremely humid and still, a zeer pot may be less effective. In that case, periodically check the temperature inside the smaller pot to make sure the produce remains at a safe temperature before consuming.
The zeer pot is not only cheap but also easy and fun to make; it is neat to have around even when you have electricity. It is cheaper than a mini-fridge and more convenient than refilling the cooler with ice to keep a six-pack cold.
Have you ever made a zeer pot or other alternative refrigeration device? Tell us about your successes and failures experimenting with other forms of refrigeration in the comments section.