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Drying / Dehydrating

WHOLE PIECES (fruits & vegetables)

Equipment

  • Drying / Dehydrating system or machine: Home Dehydrator or Oven, Commercial Dehydrator, Sun Drying system or Solar Dehydrator
  • Food-safe mesh trays for drying system
  • Optional: Hygrometer or Water Activity Meter

Instructions

Preparing the Fruits/Vegetables

  • NOTE: Unlike fruit, most vegetables need to be blanched first; exceptions include onions, mushrooms, and bell peppers (technically, a fruit).
  • Thin and uniform slices dry fastest; skins may be left on but it takes longer and often requires more diligence during the drying process.
  • If skin is left on, it should be cut or checked/cracked prior to dehydration to aid in speed. To check/crack the skin, place in boiling water for 30–60 seconds then shock in cold water. This will cause skin to split and allow center to be dried thoroughly and safely.
  • It is best practice to cut slices no more than ¼-inch thick at its widest; this will ensure heat penetrates to center of slice and dries evenly on both sides.
  • Add spices prior to dehydrating. Gently toss the fruits/vegetables in the spice mix or sprinkle lightly on top.
  • Be sure to place slices in a single layer on drying trays; pieces should not touch or overlap.
  • Optional: Fruits high in sugar can be sticky. Trays may be sprayed with nonstick cooking oil prior to placing fruit. After fruit dries ≈ 2–4 hours, lift each piece gently with a spatula and turn/rotate.

Determining Dryness

  • If you have a hygrometer (small thermostat-like device), place into an air-tight container with sample of your dried product; let sit ≳24 hours. If it measures ≈52% or less, product is dried thoroughly.
  • If you have a water activity meter, follow usage directions in meter’s manual. Water activity measurement [aW] should be at 70 or less.
  • If no instrument is available for measurement, use the following equation to determine moisture content: Dry wet/Net wet weight x100= % of remaining moisture, USDA recommends 15–20%

Packaging for Storage

  • Pack food once proper dehydration level has been reached; allow to cool first – packaging food warm can lead to sweating and moisture buildup.
  • Excessive delays in packaging could also allow moisture to re-enter food so ensure this step is completed in a timely manner.
  • If food has been dried in the sun, it must be pasteurized first before it is packaged.

DEHYDRATING TIME

  • Standard 600W Dehydrator: Refer to following chart for recommended times. ** based on continuous drying time **

Notes

Drying Fruits in a Dehydrator
❋ based on standard 600W dehydrator ❋
NOTE: These are only estimates since the ripeness of the fruit, overall moisture content of the fruit and climate humidity during dehydration will all factor into drying times.