DRYING FRUITS AND
VEGETABLES
Food Dehydration



Heat: removing moisture, but not cook
Dry Air: to absorb released moisture
Air Circulation: to carry the moisture away



Inhibits bacteria, yeast & mold growth
Prevents food spoilage
Slowing down enzymatic activity
Dry Food Safely




Peak quality
Clean preparation areas and containers
Use food grade equipment and containers
Protect food from
• Air
• Moisture
• Light
• Insects, pests/vermin
Temperatures for Drying



Herbs, nuts and seeds: 90-100°F
Fruits and vegetables: 130-140°F
Meats and fish: 160°F


Drying too slow = microorganisms could grow
Drying too fast = cooked food or case hardening

Avoid “case hardening” – dried outside and
moisture is trapped inside – mold results
Drying Methods

SUN: not recommended in Rhode Island…need
several days of high temp and low humidity

OVEN: slower than dehydrators
 FOOD DEHYDRATOR
Dehydrator Features




Double wall
construction of metal
or high grade plastic,
not wood
Enclosed heating
element
Counter top design
Enclosed thermostat
from 85ºF-160ºF





Fan or blower
4-10 open mesh trays,
plastic, sturdy,
washable
UL seal
Dial for regulating temp
A timer, auto- shut off
Types of Dehydrators
 Horizontal Air Flow
 Vertical Air Flow
Heating element and fan
are located on side
Major advantages –
reduces flavor mixing
Heating element and
fan located at base
Major disadvantage –
flavors can mix
Indoor Air Drying

Herbs, hot peppers, & nuts
in shell most common


Tie in bundles
Enclose in paper bags,
with openings for air
circulation
Spread in single layer on
paper

Drying Fruit




Wash and core
Fruits can be halved, sliced,
or whole
Thin, uniform, peeled slices
dry fastest
If fruit dried whole, crack the skin to speed
drying – cranberries – place in boiling then cold
water to “check”
Pre-Treating the Fruit


To prevent fruit darkening caused by oxidation
Optional






Sulfuring**
Sulfite Dip**
Ascorbic Acid
Ascorbic Acid Mixtures
Syrup Blanching
Steam Blanching
** can cause an allergic reaction in some people
Drying the Fruit




Place fruit in single layer
Follow directions given
Follow approximate drying times given
Watch food as it dries much faster at the end of
drying period
Determining Dryness of Fruit




20% moisture content when dried
Cut several cooled pieces in half, should not:
• see visible moisture
• be able to squeeze moisture
Not be sticky or tacky
If piece folded in half,
shouldn’t stick to itself
After Drying…

Cool fruit 30-60 minutes before packaging…don’t
pack too soon or moisture buildup could
occur…don’t wait too long or could pick up
moisture
Conditioning Fruits




Conditioning equalizes the moisture.
Pack cooled fruit in plastic or glass jars, seal and
let stand for 7-10 days
Shake jars daily to separate pieces and check for
moisture condensation
If condensation, return to dehydrator for more
drying…unless has started to mold, then dispose
of
Drying Vegetables

Preparing the vegetables
•
•
•
Wash, trim, peel, according to directions
Uniform pieces
Dry as soon as possible
after picking
Pre-treating Vegetables
Water blanching
• Recommended times
• Start timing when
water returns to boil
Steam blanching
• ≤ 2 inches above boiling water
• Heated through, but not cooked
• Lose less water-soluble vitamins & minerals
Cooling Vegetables

Cool

Wipe vegetables

Place in dehydrator
Determining Dryness of Veggies



Dry vegetables until brittle or “crisp”
10% Moisture
Don’t need conditioning
like fruits, because they
have a lower
moisture content
Drying Jerkey

Jerky can be made from:
• Meat (sliced cuts, ground)
• Fish (fillets)
• Poultry (breasts)

Two drying methods
• Dry, then heat
• Heat, then dry**
Disclaimer:
 Trade and brand names are used only for information. The University of
Rhode Island does not guarantee nor warrant published standards on any
product mentioned; neither does the use of a trade or brand name imply
approval of any product to the exclusion of others which may also be suitable.
Document Use:
 So Easy to Preserve, 5th Edition, 2006, University of Georgia Cooperative
Extension Service
 Adapted with permission of the University of Illinois. Finck, J. 2011. Drying
Foods (slides). Springfield, IL: The University of Illinois, Extension.
 Ball® Complete Book of Home Preserving, Ed. J. Kingry and L. Devine, 2006.
Robert Rose Inc.
Photography Credits
 Elizabeth Andress and Elaine D’Sa, National Center for Home Food
Preservation, University of Georgia.
 Information Staff, Agricultural Research Service, USDA.
 North Caroline State University
20