University of Vermont Extension
Department of Plant and Soil Science
Fall
News
Article
DRYING
VEGETABLES
Dr.
Leonard Perry, Extension Professor
University of Vermont
Are
you getting overrun with vegetables from the garden, and wonder what to
do with
them? Or, perhaps you are just looking
for an easy way to preserve your produce or that from local farms and
farmers'
markets. In addition to freezing, drying
or dehydrating is perhaps the easiest way to preserve vegetables.
It
is the oldest method, yet perhaps the
least used.
Successfully drying vegetables depends on four factors: selection
of
produce at peak flavor and
quality, blanching to stop decomposition and ripening, proper heat and
drying
conditions, and proper storage. Store
cool, dry and dark as in a cellar, refrigerator, or if freezing use
special
freezer containers or bags made for this purpose. Other
containers and
bags may not be
moisture-proof, resulting in shriveling and freezer burn. Dried
vegetables, properly stored, last for 6
to 12 months. As they aren't quite the
same taste and texture as fresh, they are best used in soups,
casseroles,
sauces and stews.
When
produce is picked, enzymes are activated that result in
decomposition.
To stop these, blanching is used for many
vegetables. This is merely boiling for
short periods, time varying with the crop.
Blanching by steaming, instead of boiling, will help to preserve more
nutrients. Properly blanched, vegetables
will be heated through but won't be cooked.
Test a piece by cutting to see if it is cooked (translucent) nearly to
the center.
An
easy way to blanch is to place a quart of produce, once cleaned and
washed, in
the middle of a 2 or 3 foot square piece of cheesecloth. Gather
the
corners and immerse in boiling
water, making sure water reaches all produce in the
bag. Remove after the time suggested for
each crop, immerse in cold water to cool quickly, for the same amount
of
time. Then drain on cloth or paper
towels. Homebrew shops sell bags for
grains that work well for this purpose too.
When
blanching, you may wish to add some citric acid to the water to prevent
darkening and to kill any harmful microbes.
Use 1/4 teaspoon of citric acid to one quart of water. Most
vegetables
should be blanched for about
3 to 4 minutes. Use longer (5 to 6
minutes) for Brussels sprouts, cut corn, and potatoes. Use no blanching
for
herbs, onions, peppers, horseradish, and tomatoes.
Tomatoes
should be dipped in boiling water for under a minute until skins split,
then
cold water to loosen skins and make peeling easy. Then slice or
cut in
sections, and soak for
10 minutes in one teaspoon of citric acid to one quart of water.
It is
often easier to prepare vegetables as you would for cooking by cutting
or
slicing prior to blanching. Corn is
easier blanched, then taken off the cob.
To dry you may spread on trays in the sun, in the oven, or use a
dehydrator. If using the sun, you really
need about 3 days at 90 degrees (F) or above so the produce dries
without
molding first. This may be difficult in
cool climates or summers. A solar method some use is to spread on trays
and
place in cars on the dash or back window ledges on summer days. If you
get a cloudy
day, though, and the produce isn't dry you may have to finish using
another
method to avoid spoilage.
If
using an oven for drying vegetables, the key is to dry at the correct
temperature: under 200 degrees (F), preferably around 140
degrees.
Some ovens may not get this low. If too cool, produce wont dry
properly or
quickly enough. If too hot, they will
cook instead of merely dry. Check every
half hour to make sure the temperature is correct (an oven thermometer
is
useful), to allow moist air to escape, and to rotate trays for
uniform drying. Make sure produce is no
more
than one half-inch deep on trays, or stir often. Keep about 2 to
3
inches between trays.
If
using your own trays for drying, don't use galvanized screening as the
metals
in it can cause harmful reactions with acid foods. Aluminum may
corrode and discolor with use.
If using these, line with cheesecloth to prevent produce from touching
the
metal. Wash trays well between uses, and
a light coating of spray cooking oil makes cleaning easier.
Thermostatically-controlled dehydrators can be purchased at many
appliance stores, and
are preferable as they use much less electricity and
dry at the proper temperature, are convenient, easy, and not too
expensive. Depending on the model, you
may need to rotate trays during the drying process so all vegetables
are dried
uniformly. Herbs dry best with these, as
they only require about 110 degrees-- too low for most ovens. You
may
consider freezing herbs instead, as
they will lose less flavor and oils than with drying.
Depending
on your heat source and level, and water content of the crop, figure on
6 to 12
hours for drying. Less is needed for
parsley and herbs. Twelve or more hours
may be needed for broccoli, Brussels sprouts, cauliflower, chili
peppers,
eggplant, squash, and some tomatoes.
Drying in dehydrators goes fastest on less humid days and by not
overloading the dryer.
To
test for dryness, take a sample and allow to cool for a few
minutes.
When warm, produce feels soft and
supple. Dried properly, it should feel
crisp and brittle, although this varies some with the crop. Peas
will
be hard and wrinkled, spinach and
greens will be crisp, herbs will be flaky, squash and eggplant will be
leathery.
Keep
in mind dried produce occupies much less space in storage than fresh:
15 pounds
of carrots yield just over a pound of dried product or about 2 to 4
pints, for
instance. For peas, 8 pounds fresh yield
about one pint dried, for snap beans 6 pounds fresh yield about 2 and a
half
pounds dried.
In
general, you might figure that one cup of dried vegetables will
reconstitute to
about 2
cups. To cook
dried, leafy or tender vegetables (such as spinach, cabbage, or
tomatoes),
cover with hot water and simmer until tender.
To cook root, stem and seed vegetables (such as carrots, green beans,
peas and corn), first soak for 30 to 90 minutes in cool water or cover
with
boiling water and soak for 20 to 60 minutes.
Then, simmer these presoaked vegetables until tender.
Whether
you preserve vegetables by drying or other means, it enables you to
continue
enjoying varieties through the fall and winter you wont find in stores,
can
save you money, and you don't have to worry about safety issues knowing
just
where your produce came from.
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Perry's Perennial
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