The clay pot cooler (zeer)

In short

• A clay pot cooler cools by evaporation. It works best on a dry, warm, breezy day, in the shade.
• On a dry day it gives roughly 5–8 °C less than the air (more in a dry continental climate); on a muggy day only 1–3 °C. In a damp UK or Irish summer, often 2–4 °C. Inside, the air is humid, so vegetables do not wilt.
• For vegetables, fruit and leafy greens: roughly 2–3 times longer than on the kitchen table.
• Not for meat, milk, fresh cheese or cooked food. They need 0–4 °C (H57-01).
• The outer pot must be unglazed. Food must not touch glaze of unknown origin (lead).
• Water the sand 1–3 times a day, and every 2–4 weeks empty the cooler and dry it in the sun.

What's inside

Chapters

1. How a clay pot cooler works
2. How much it cools in your climate
3. What goes in the cooler and what does not
4. Pots and materials
5. Making it step by step
6. Placing it and daily care
7. A larger cooler: the brick chamber
8. Cleanliness, mould and mosquitoes
9. A clay cooler for water and drinks
10. Safety
11. Common mistakes
12. Printable checklist

Worksheets

• Sand, water and cost calculator
• My pot sizes
• Test log
• What is in the cooler
• The clay pot cooler season