How food dehydrating works
A dehydrator combines gentle heat with steady airflow to remove water from food. With most of the water gone, bacteria, yeasts and molds can't grow, so fruit, vegetables, herbs and jerky keep for months. Fresh produce is mostly water – apples are about 84 %, strawberries over 90 % – so the dried yield is only a small fraction of what you start with. DryRight calculates it from the water content before and after drying.
Dried weight = fresh weight × (1 − water %) ÷ (1 − final moisture %)
Temperatures and times
| Food | Temperature | Time | Done when |
|---|
| Herbs | 95 – 115 °F (35 – 46 °C) | 2 – 4 h | Leaves crumble |
| Vegetables | 125 °F (52 °C) | 4 – 12 h | Brittle or leathery |
| Fruit | 135 °F (57 °C) | 6 – 14 h | Leathery, no moisture when squeezed |
| Jerky | 145 – 155 °F (63 – 68 °C) after pre-heating meat | 4 – 8 h | Bends and cracks, doesn't snap |
Times depend on slice thickness, the food's sugar content, room humidity and your dehydrator's airflow. Check early and remove pieces as they finish.
Jerky safety
Dehydrator temperatures alone may not destroy pathogens in meat. USDA recommends heating meat to 160 °F (71 °C) – poultry to 165 °F (74 °C) – before drying, for example by steaming or roasting the strips, or heating the dried jerky in a 275 °F (135 °C) oven for about 10 minutes. Use lean meat and trim fat, which can turn rancid.
Choosing a dehydrator
- Horizontal airflow (rear fan, box-style) dries evenly without rotating trays and handles jerky and different foods at once.
- Vertical airflow (stackable round) is cheaper and expandable but needs tray rotation.
- Adjustable thermostat from about 95 °F to 160 °F, and a timer with auto shut-off.
- Tray area: count total square inches – a box unit with 9 × 225 sq in trays dries over 10 lb of fresh fruit per batch.
- Stainless trays and fruit-leather sheets for flexibility; BPA-free plastic otherwise.
Storage
Cool dried food completely, then store in airtight jars or vacuum-sealed bags in a cool, dark place. Fruit and vegetables keep for 6 – 12 months; jerky about 1 – 2 months at room temperature or longer in the fridge or freezer.
Frequently asked questions
How long does it take to dehydrate apples?
About 6 – 12 hours at 135 °F (57 °C) for ¼-inch slices, until leathery with no moisture when squeezed.
How much dried fruit do I get from fresh?
Usually 10 – 20 % of the fresh weight. Four pounds of apples make roughly 0.7 – 0.8 lb of dried slices.
What temperature should I dehydrate at?
Herbs 95 – 115 °F, vegetables 125 °F, fruit 135 °F, and jerky 145 – 155 °F after pre-heating the meat to 160 °F.
Is homemade jerky safe from a dehydrator?
Follow USDA guidance: heat the meat to 160 °F (165 °F for poultry) before or after drying, since dehydrator temperatures alone may not be enough.
How much does it cost to run a dehydrator?
A 600 W unit running 10 hours with the heater cycling uses about 3 – 4 kWh, roughly 50 – 70 cents at average prices.
About DryRight
DryRight is an independent, free calculator for home food dehydrating, based on National Center for Home Food Preservation and USDA guidance. Drying times vary with slice thickness, humidity and the appliance. We are not affiliated with any appliance brand.
Every formula on this page runs entirely in your web browser. The numbers you type are never uploaded, stored or shared. Our goal is simple: give you an honest starting point so you can compare product specifications with confidence and avoid paying for capacity you do not need – or buying something too small to do the job.
The methodology combines widely published engineering rules of thumb, manufacturer data sheets and the electrical code practices that installers use every day. We review the assumptions regularly and update the calculator when typical product specifications change.
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Last updated: October 28, 2026
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