Wood-fired and solar dryers

In short

• Every dryer works the same way: cool air comes in at the bottom, warms up, passes through the trays and leaves at the top with the moisture.
• In a wood-fired dryer the smoke goes through the heat-exchanger pipe into the chimney, not through the food: no soot, tar or CO in the chamber.
• On the trays fruit 55–65 °C, vegetables 50–60 °C; the bottom tray is the hottest, so the trays are swapped every 2–4 hours.
• A wood-fired dryer stands on its own, on a non-combustible base, away from hay and the woodshed, with a fire extinguisher, and is never left burning unattended.
• A solar dryer with 2–3 m² of collector dries 10–20 kg of fresh fruit in 2–3 sunny days, with no fuel cost.

What's inside

Chapters

1. How a dryer works
2. A small wood-fired dryer: building it
3. Firing and running a wood-fired dryer
4. Fire, smoke and carbon monoxide
5. Solar dryer: the direct box
6. Solar dryer with a collector
7. Electric dehydrator, oven and range
8. Maintenance and end of season
9. Common mistakes
10. Printable checklist

Worksheets

• Building and season calendar
• Dryer cost sheet
• Capacity and electricity
• Firing log
• Pre-firing check
• Dryer sketch