Sunday, March 25, 2012

Drying Foods for Storage



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Drying or dehydration, the oldest method of food preservation, is particularly

successful in the hot, dry climates found in much of New Mexico. Quite simply,

drying reduces moisture necessary for bacterial growth that eventually causes

deterioration.

Successful dehydration depends upon a slow steady heat supply to assure that

food is dried from the inside to the outside. Drying is also an inexact art. Size of

pieces, relative moisture, and the method selected all affect the time required to

dehydrate a food adequately.

Methods of Drying

Foods may be sun dried with or without a solar dehydrator, in a gas or electric

oven, or with a portable electric dehydrator. Dehydrators with thermostats provide

better control over poor weather conditions and food quality than sun drying.

An effective solar dehydrator is the shelf above the back seat of a car. Clotheslines

are another popular drying rack for ears of corn and strips of jerky. Colorful red

chile ristras hung from vigas are practical as well as decorative.

Sun drying. Prepared foods are placed on drying trays. Stainless steel screening

and thin wood lath are good materials for home-constructed drying trays. As

aluminum screening reacts with acids in the fruit, it is less desirable. Do not use

galvanized, copper, fiberglass, or vinyl screening.

Trays measuring about 14" x 24" x 1" are an easy size to handle. If trays are to be

used in an oven, they should be 1 1/2" smaller in length and width than oven

shelves to allow air circulation.

Place trays of food away from dusty roads and yards. Elevate them at least 1"

above the table with spools or bricks to allow good air circulation below the food.

Cover the food with a muslin or cheesecloth tent to protect it from insects. Dry

fruits and meats in direct sunlight; move trays periodically to assure direct sun

exposure. Place vegetables in the shade to prevent excessive color loss.

If rain threatens or food requires more than one day to dry, cover with a waterproof

material or place the food in a sheltered area.

To destroy insects or their eggs that may be on sun-dried foods and to remove

additional moisture in thicker pieces, heat foods in a 150 degree oven for 30 min.

Oven drying. Either build trays as described for sun drying or convert oven racks

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to drying racks by stretching muslin or cheesecloth across the oven rack. Secure

with toothpicks or long sewn stitches. Alternate trays in the oven periodically to

assure even drying.

Set oven control at its lowest setting, but not below 140-150 degrees. If using an

electric oven, wedge a potholder between oven and door to allow a 1" opening.

Moisture from the drying food will vent through this opening. Close the door on a

gas oven, as into vent will permit moisture to escape.

Dehydrator. There are two types of dehydrators: solar and electric. For each type

of dehydrator, prepare food and place on racks. If using a solar dehydrator, adjust

the position of the food throughout daylight hours to keep in direct sunlight.

Follow manufacturer's instructions for the electric dehydrators. When purchasing

an electric dehydrator, select one that has a thermostat to regulate temperature

and a fan to circulate air.

General Directions for Preparing Foods for Drying. Refer to the tables at the

end of this guide for instructions for specific foods.

Vegetables. Choose tender vegetables. Wash, remove any damaged areas, and

cut into even pieces. Blanch, then chill as though preparing for the freezer. Note:

Do not blanch mushrooms, onions, or sweet peppers.

To blanch in boiling water, use one pound of food for each gallon of boiling water.

Immerse vegetable into the boiling water using a wire basket or mesh bag, cover

kettle, and boil the recommended time (see table). Blanching water may be reused

until it becomes cloudy. Drain vegetables thoroughly.

To steam blanch, place 1" of water in kettle and bring to a rolling boil. Suspend thin

layer of vegetables in basket or loose cheesecloth bag. Cover and steam blanch

required amount of time (see table).

Fruit. Choose firm, mature fruit. Wash, peel if desired, remove any damaged

areas, and cut into even-sized pieces or slices. Some fruits require little or no

pretreatment. However, pretreat apples, apricots, bananas, cherries, peaches, and

pears by one of the following methods to reduce vitamin and flavor loss, browning,

and deterioration during storage.

Immerse fruit in a solution of one of the following to a gallon of water: 1 tbsp of

sodium bisulfate or 2 tbsp of sodium sulfite or 4 tbsp of sodium metabisulfite.

These pretreatment mixtures are available from some grocery stores, pharmacies,

and wine-making shops. Soak fruit pieces for 5 min. and fruit halves for 15 min.

Note: Approximately 5% of asthmatics are sensitive to sulfites. Use one of the

following pretreatments if sulfites present a potential health problem:

Dip fruit in a commercial ascorbic acid/water mixture from the grocery store. Follow

manufacturer's instructions when preparing and using the solution.

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Steam blanch fruit for 5-6 min.; water blanch fruit for 4-5 min. (see information on

water and steam blanching above).

Dip prepared fruit in a saline solution composed of 2-4 tbsp of salt and l gallon of

water for 10-15 min.

Meat. Choose lean cuts of beef or venison. Partially freeze and remove all visible

fat. Slice with the grain of the meat into strips, 1" wide, 1/2" thick and 8-10" long.

Pound strips flat to tenderize and season with salt, chile, or other desired flavors.

Marinate and refrigerate overnight for additional tenderness and flavor. Popular

marinades include teriyaki, sweet and sour, soy, Worcestershire, and chile sauces.

Fish. Slice salmon filets into thin strips. Place strips in a dish or enamel pan. Salt

strips using 2 tbsp. salt per pound. Refrigerate overnight. Oven or dehydrator

drying is preferable to sun drying fish.

Drying Times

Drying time varies widely because of the method selected and the size and

amount of moisture in food pieces. Sun drying requires the most time; an electric

dehydrator requires the least. Vegetables take from 4-12 hours to dry; fruits take 6-

20 hours. Meats require about 12 hours. Making raisins from grapes may require

days/weeks when dried outside.

When testing foods for dryness, remove a piece from the center of the drying tray

and allow it to come to room temperature. Fruits and meat jerky should be leathery

and pliable; vegetables should be brittle.

Conditioning Dried Foods

Food should be conditioned for a week before being packaged for long-term

storage. To condition food, place it in a container such as a cloth sack or a clear,

covered container and allowing any remaining moisture to redistribute itself

through the fruit.

If using a clear, covered container, watch for moisture beads. If they form, continue

drying food. If using the cloth bag, hang it in a convenient location and shake the

bag daily to redistribute food and moisture.

Storing Dried Foods

Place dried food in freezer-weight plastic storage bags, press out air, and then put

in containers with a tight-fitting lid. Store in a cool, dark, dry area.

Dried foods store well at room temperature for a month. Refrigerate foods if they

will be used within three months; freeze foods for storage periods between three

months and one year. Foods should be used within one year.

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Instructions for Specific Food Drying

VEGATABLES (See text for general directions)

Using Dried Foods

Dried meat, commonly called jerky, is normally not rehydrated and is eaten in the

dried state. Dried meats and vegetables used in soups rehydrate during the

cooking process.

Rehydrate vegetables by soaking them in 1 1/2-2 cups of water for each cup of

dried vegetable. If necessary, add more water during the soaking process. Heat

and eat.

Cover dried fruit with boiling water and let stand for 5 min. Drain. Dried fruit may

also be steamed for 3-5 min. until plump. Fruits may be eaten immediately or used

in a recipe.

Making Fruit Leather

Fruit leathers, also called fruit roll ups, can be made from almost all fruits or

combinations of fruits. However, peaches, apricots, cherries, and nectarines are

ideal. Pears and apples, sufficiently softened, also work well.

Wash well, peel (if desired), cut into pieces, and puree fruit in a blender. Sweeten

to taste with sugar or honey. Spread evenly, no more than 1/4" deep, on a cookie

sheet. The cookie sheet should either be lightly sprayed with a vegetable

shortening or covered with plastic paper.

If using plastic paper, tape edges down to prevent them from folding into the

puree. Dry fruit leather until it is slightly tacky to the touch.

When dried, lift leather (including plastic paper if used), and roll or cut into small

sections and roll. Storage recommendations are the same as those described

previously.

Nutritional Value of Dried Foods

Dried foods retain their protein, mineral and vitamin A content fairly well if soaking

water is also consumed. Because they are concentrated into a small mass, dried

foods can also be high in calories. It's important to brush teeth after eating dried

fruit because they stick to the teeth.

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Vegetable Preparation

Blanching

Time(mins.)

with Steam

Cooling Time

(mins.) with

Cool Water

Dryness Test

Asparagus

Wash

thoroughly.Halve

large tips.

4-6 4-5 Leathery to

brittle

Green Beans Wash. Cut in

pieces or strips. 2-3 2 Very dry brittle

Beets

Cook as usual.

Cool & peel. Cut

into shoe-string

strips 1/8" thick.

Included in

cooking

Included in

cooking

Brittle, dark

red

Broccoli

Trim, cut as for

serving Wash.

Quarter stalks

lengthwise.

3-4 2 Crisp, brittle

Brusselssprouts

Cut in half

length-wise

through stem.

7-8 5-6 Tough to

brittle

Cabbage

Remove outer

leaves quarter

and core. Cut

into strips 1/8"

thick.

3 2 Crisp to brittle

Carrots

Select crisp,

tender

vegetables.

Wash. Cut off

roots and tops,

peel. Cut in

slices or strips

1/8" thick.

3-4 4 Tough to

brittle

Cauliflower Prepare as for

serving. 5-6 4-5 Tough to

brittle

Celery

Trim stalks.

Wash stalks and

leaves

thoroughly, Slice

stalks.

2-3 2-3 Very brittle

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Green Chile

Peppers

Wash. To

loosen skins, cut

slit in skin, then

rotate over

flame 6-8 min.

or scald in

boiling water.

Peel and split

pods. Remove

seeds and stem.

None None Crisp, brittle,

medium green

Red Chile

Peppers

Wash. String

whole pods

together with

needle and cord

or suspend in

bunches, root

side up in area

with good air

circulation.

None None

Shrunken,

dark redpods,

flexible

Corn on the

Cob

Husk, trim,

blanch until milk

in corn is set.

3-5 3 Brittle

Corn, cut

Prepare as for

corn on the cob,

except cut the

kernels from the

cob after

blanching.

3-5 3 Brittle

Eggplant Wash, trim, cut

into 1/4" slices. 3-4 3-4 Leathery to

brittle

Horseradish

Wash, remove

small roots and

stubs. Peel or

scrape roots.

Grate.

None None Brittle,

powdery

Mushrooms

(see note

below)

Scrub. Discard

tough woody

stalks. Slice

tender stalks

1/4" thick. Peel

large

mushrooms,

slice. Leave

small

mushrooms

whole.

None None Dry and

leathery

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Onions

Wash, remove

outer

"papershells."

Remove tops

and root ends,

slice 1/8-1/4"

thick.

None None Very brittle

Parsley and

other herbs

Wash

thoroughly.

Separate

clusters. discard

long or tough

stems. Dry on

trays or hang in

bundles in area

with good

circulation.

None None Flaky

Peas Shell. 3-4 3

Hard,

wrinkled,

green

Peppers and

pimentos

Wash, stem.

Remove core

and seeds. Cut

into 1/4"-1/2"

strips or rings.

None None Tough to

brittle

Potatoes

Wash, peel. Cut

into 1/4" shoestring

strips or

1/8" thick slices.

7-9 6-7 Brittle

Spinach and

other greens

(kale, chard,

mustard)

Trim and wash

very thoroughly.

Shake or pat dry

to remove

excess

moisture.

2-3 (until

wilted) 2 Crisp

Squash,

winter

Cut or break into

pieces. Remove

seeds and cavity

pulp. Cut into 1"

wide strips. Peel

rind. Cut strips

crosswise into

pieces about

1/8" thick.

3 1-2 Tough to

brittle

Squash,

summer or

banana

Wash trim, cut

into 1/4" slices. 3 1-2 Leathery to

brittle

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Instructions for Specific Food Drying

FRUITS (See text for general directions.)

Tomatoes

Steam or dip in

boiling water to

loosen skins.

Chill in cold

water. Peel.

Slice 1/2" thick

or cut in 3/4"

sections.

None None Crisp

Fruit Preparation Pretreatment Drying Procedure

Apples

Wash. Pare, if

desired, and core.

Cut in rings or

slices 1/8-1/4" thick

or cut in quarters

or eighths Coat

with ascorbic acid

solution to prevent

darkening during

preparation (uses

2 1/4 tsp/cup

water).

Choose one: Soak

5 min in sodium

sulfite solution.

Steam-blanch 3-5

min., depending on

size and texture.

Arrange in single

layer trays, pit side

up. Dry until soft,

pliable and

leathery; no moist

area in center

when cut.

Apricots (firm, fully

ripe)

Wash. Cut in half

and remove pit (do

not peel). Coat

with ascorbic acid

solution to prevent

darkening during

preparation (1

tsp/cup).

Choose one: Soak

5 min. in sodium

sulfite solution.

Steam blanch 3-5

min.

Arrange in single

layer trays, pit side

layer up; pop the

cavity up to expose

more flesh to air.

Dry until soft

pliable and

leathery; no moist

area in center

when cut.

Bananas (firm,

ripe)

Peel. Cut in 1/8"

slices

No treatment

necessary; may

dip in lemon juice.

Arrange in single

layer on trays. Dry

until tough and

leathery.

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Berries (firm)

Wash. Leave

whole or cut in

half.

No treatment

necessary; may

dip in boiling water

15-30 sec., to

crack skins. Steam

blanch 30 sec. to 1

min.

Spread in layer not

more than two

berries deep. Dry

until hard and

berries rattle when

shaken on trays.

Cherries (fully ripe) Wash. Remove

stems and pits.

No treatment

necessary; may

dip whole cherries

in boiling water 15-

30 sec. crack

skins.

Arrange in single

layer on trays. Dry

until tough,

leathery and to

slightly sticky.

Citrus peel (thickskinned

with no

signs of mold or

decay and no color

added)

Wash. Thinly peel

outer 1/16-1/8" of

the peel; avoid

white bitter part.

No pretreatment

necessary.

Arrange in single

layers on trays.

Dry at 130 degrees

1-2 hours; then

120 degrees until

crisp.

Figs (fully ripe)

Wash or clean with

damp towel. Peel

dark-skinned

varieties if desired.

Leave whole if

small or partly

dried on tree; cut

large fig in halves

or slices.

No treatment

necessary; may

crack skins of

whole figs in

boiling water 15-30

sec.

Arrange in single

layer on trays. Dry

until leathery and

pliable.

Grapes (seedless

varieties)

Wash, sort, leave

whole on stems in

small bunches, if

desired, May also

remove stems.

No treatment

necessary; may

crack skins in

boiling water 15-30

sec. Steam blanch

1 min.

Spread in thin

layer on trays. Dry

until pliable and

leathery with no

moist center.

Melons (mature,

firm and heavy for

size: cantaloupe

dries better than

watermelon)

Wash. Remove

outer skin, any

fibrous tissue and

seeds. Slice 1/4-

1/2" thick.

No pretreatment

necessary.

Arrange in single

layer on trays. Dry

until leathery and

pliable with no

pockets of

moisture.

Peel. Cut in half Arrange in single

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Nectarines and

Peaches (ripe,

firm)

and remove pit.

Cut in quarters or

slices if desired.

Coat with ascorbic

acid solution to

prevent darkening

during preparation

(1-tsp/cup)

Choose one: Soak

5-15 min in sodium

sulfite. Steam

blanch halves 8-10

min., slices 2-3

min.

Arrange in single

layer on trays pit

side up. Turn

halves over when

visible juice

disappears. Dry

until leathery and

somewhat pliable.

Pears (Bartlett

variety is

recommended)

Wash. Pare, if

desired. Cut in half

lengthwise wash

and core. Cut in

quarters or eighths

or slice 1/8-1/4"

thick. Coat with

ascorbic acid

solution to prevent

darkening during

preparation (1-

tsp/cup)

Choose one: Soak

5-15 min. in

sodium sulfite.

Steam blanch 5-7

min.

Arrange in single

layer on trays pit

side up. Dry until

springy and suede

like with no

pockets of

moisture.

Plums and prunes

Wash. Leave

whole if small; cut

large fruit into

halves (pit

removed) or slices.

No treatment

necessary; may

choose: Steam

blanch halves or

slices 5-7 min.

Crack skins in

boiling water 1-2

min.

Arrange in single

layer on trays pit

side up, cavity

popped out. Dry

until pliable and

leathery; pit should

not slip when

squeezed if prune

not cut.

(1) Blanching times are for 3,000-5,000 ft. Times will be slightly longer at higher

altitudes, or if the quantity of vegetable is large.

(2) Dry in thin layers on trays to desired state of dryness.

(3)WARNING: The toxins of poisonous varieties of mushrooms are not destroyed

by drying or by cooking. Only an expert can differentiate between poisonous and

edible varieties.

By Alice Jane Hendley, Extension Diet and Health Specialist . New Mexico State

University is an equal opportunity/affirmative action employer and educator. NMSU

and the U.S. Department of Agriculture cooperating.

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