← Food Preservation
ConditionalBeginner · 1 hour
Zeer Pot Evaporative Cooler
Two clay pots and wet sand can keep produce cool — in the right climate.
Question 1
The goal
Extend the life of fruits and vegetables without electricity.
Question 2
Materials
- Two unglazed terracotta pots (one fits inside the other with a 3–5 cm gap)
- Sand
- Water
- Damp cloth
Question 3
Substitutes
- Stacked buckets wrapped in wet burlap
- Charcoal cooler box with wet walls
Where to find it
| Material | Household | Wilderness | Urban / scavenged |
|---|---|---|---|
| Unglazed clay pots | Garden terracotta planters | Not practical | Garden centers |
| Sand | Play sand, kitty litter (unscented) | Riverbank sand | Construction sites (ask) |
Question 4
Step by step
- 1
Plug drainage holes and place a sand layer in the large pot.
- 2
Center the small pot and fill the gap with sand.
- 3
Soak the sand with water until saturated.
- 4
Load produce and cover with a damp cloth.
- 5
Keep in shade with airflow; rewet sand twice daily.
Saved steps go to My Survival Notebook.
Question 5
The science
Evaporation absorbs latent heat (~2,260 J per gram of water) from the outer pot. Dry, breezy air speeds evaporation; humid air slows it.
Question 6
Dangers & limits
- NOT a safe refrigerator for meat, dairy or leftovers — those need ≤ 4 °C (40 °F).
- Weak in humid climates like Florida — expect only a few degrees of cooling there.
Question 7
How you know it worked
The inner pot feels noticeably cooler than air temperature and produce lasts longer.
My notes
Notes save on this device automatically.