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- Drying food at home
Dried foods are tasty, nutritious, lightweight, easy to prepare, easy to carry and easy to use. Low humidity, low heat and good air circulation are critical for successful drying. You can use a dehydrator, oven, microwave or even air-dry some foods. Start with good quality foods. Blanch vegetables first and pretreat most fruit. Remember, successful drying takes time. Once dry, store foods in a dark, cool location in containers that keep out moisture and insects.
How does drying keep food from spoiling?
Drying or “dehydrating” food is a method of food preservation that removes enough moisture from the food so bacteria, yeast and molds cannot grow.
How to dry food safely
By using the right combination of warmth, low humidity and air current, you can safely dry foods. To dry foods successfully you need:
Low humidity. Low humidity allows moisture to move from the food to the air.
A source of low heat. The warm temperature allows the moisture to evaporate.
Air circulation. Air currents speed up drying.
Note: Sun drying is not recommended in Minnesota due to high humidity and cool night temperatures.
Watch our 5-minute video on drying foods
Mini module: dry it you'll like it
Methods of drying food
Dehydrators
Produce the best quality product as compared to other methods of drying.
Most food dehydrators have an electric element for heat and a fan and vents for air circulation.
Efficient dehydrators are designed to dry foods uniformly and to retain food quality.
Oven drying
An oven takes 2 to 3 times longer to dry food than a dehydrator. Drying in an oven is slower because ovens do not have built-in fans for the air movement.
The oven uses a great deal more energy than a dehydrator.
To use your oven for drying:
Check the oven dial to see if it has a reading as low as 140 F or use the ‘keep warm’ setting. If the thermostat does not go this low, your food will cook instead of dry.
An oven thermometer placed near the food gives an accurate reading of the drying temperature.
Leave the oven door propped open 2-4 inches and place a fan near the outside of the oven door to improve air circulation.
Sun drying
Sun-drying is not recommended in Minnesota due to our high humidity and cool night temperatures.
Foods dried in the sun can take 3-4 days to dry; if the humidity is high, as is generally the case in Minnesota, the food will mold before it dries.
Sun-drying requires constant exposure to direct sunlight during the day and a relative humidity of less than 20%. These conditions are found only in areas like the Sacramento Valley of California or in Arizona.
Air drying
Air drying differs from sun-drying, since it takes place indoors in a well ventilated attic, room or screened-in porch.
Herbs, hot peppers and mushrooms are the most common air-dried items.
Herbs and peppers are not pretreated, but simply strung on a string or tied in bundles and suspended until dry.
Enclose them in paper bags to protect them from dust or other pollutants.
Microwave drying
Is a quick way to dry small quantities of herbs and some leaf vegetables, but it is not successful for most other foods.
Food which has been microwave dried often tastes overcooked rather than dried.
To dry small quantities of herbs:
Place no more than 4 or 5 herb branches between two paper towels and microwave for 2-3 minutes.
Remove the herbs. When cool, check to see if they are dry and brittle. If not, repeat drying for 30-second intervals until dry.
What to consider
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Select fresh, good quality fruits and vegetables.
Peel and trim away seeds, core or damaged portions.
Cut into halves, strips, or slices about 1/8-inch to 1/4-inch thick that dry readily.
Blanch vegetables by heating them enough to neutralize enzymes. If you omit this step, or inadequately blanch vegetables, they will have poor flavor and color. Blanch in steam or in hot water. Water blanching is quicker, but may leach out color and nutrients compared to steam blanching. Follow the same times as used when freezing vegetables. It is not necessary to chill blanched vegetables. Drain them well and spread onto drying rack in oven or food dehydrator.
Pretreat most fruits by dipping them to slow down browning. Use 1/2 teaspoon Vitamin C (ascorbic acid) per quart of cold water. Dip fruit for 1 minute, then drain and put on rack to begin drying.
Drying food is a slow process:
In a dehydrator, it takes at least 6 hours to dry foods.
In the oven, it takes at least 8 hours.
Drying time depends on:
The type of food.
The thickness of the cut.
The moisture content of the food.
The drying method.
Don't speed up the drying time by turning up the oven.
You will cook the food on the outside before it dries on the inside. This is called "case hardening." The food may appear dry on the outside but is wet on the inside. It will mold later on in storage.
Check for dryness and cool before storing
Vegetables are dry when they are brittle, fruits when they feel like leather. After foods are dried, allow 30-60 minutes cooling time. Too long a cooling period allows moisture from the air to re-enter the food.
Choose the right storage container
Proper storage prevents insects and rodents from eating the food. It also keeps moisture out and saves nutrients.
Use glass jars, metal cans or boxes with tight-fitting lids or vapor-proof freezer cartons.
Screw lids or covers on glass jars to prevent insect contamination, but it is not necessary to heat-process the jars.
Heavy-duty plastic bags with press-together seals are acceptable, but are not insect- or rodent-proof.
Check containers within 7-10 days to see if moisture is present. If you see moisture, remove food and redry. If food is moldy, discard it, throw away the plastic freezer bag or sterilize the jar.
Shelf life of dried food
Dried foods keep 4-12 months depending on storage conditions.
Store in cool, dry, dark areas.
For best quality, store under 60 F. Although it is not necessary to store dried food in a refrigerator or freezer, except for meat jerky, low temperatures extend the shelf life.
Using dried fruits
Dried fruits can be eaten as nutritious snacks or soaked for 1-2 hours and used in favorite recipes.
Fruits that dry well for snacks are apples, apricots, bananas and pears.
Fruit leathers made from overripe fruit make nutritious snacks.
Using dried vegetables
Dried vegetables are usually reconstituted and are best used as ingredients for hot dishes, sauces or stuffing. However, if adding dried vegetables to a soup or stew, no need to rehydrate,just toss them in.
To reconstitute or rehydrate, cook leafy or tender vegetables (e.g. spinach, kale, cabbage, tomatoes), cover with hot water and simmer to desired tenderness. Soak root and seed vegetables (e.g. carrots, green beans, peas, corn) before cooking. Cover with cold water and soak 30-90 minutes, or cover with boiling water and soak 20-60 minutes. After soaking, simmer until tender.
CAUTION: If soaking takes more than 2 hours, refrigerate the product for the remainder of the time to prevent bacterial growth.
One cup of dried vegetables equals about 2 cups of reconstituted vegetables. Once reconstituted, dried fruits or vegetables are treated as fresh.
You can use the dried vegetables directly:
Dried sliced vegetables can be eaten as tasty vegetable chips for dips.
Vegetables can be added directly to soups or stews drawing on the liquid in the soup or stew for rehydration during cooking.
Chop and dry green pepper, onion, celery and chives for use instantly all year.
Make your own onion powder by drying onion slices until crisp and powder in the blender.
Grate carrots for use in salads, carrot cake, soups, stews or casseroles.
Save money. You will be able to reap the rewards of your own garden, but it will also allow you to take advantage of supermarket specials.
Less waste. Keep in mind that food drying is a one-time cost. Canned foods, once opened, must be used promptly, but containers of dried foods can be repeatedly opened, ingredients removed or added, and closed again with no ill effects on the contents.
Convenient food. Dried food is super-convenient because it can be eaten just the way it is.
Store a larger quantity. You are able to store more food in far less space than canned or frozen food.
Better flavor. Gives you natural snacks with "extreme" flavor.
Nutritional quality. Retains more nutritional quality than canned or frozen food.
Easy! Dried foods are tasty, nutritious, lightweight, easy to prepare, easy to carry, and easy to use.
National Center for Home Food Preservation, Drying Vegetables video.
Suzanne Driessen, Extension educator and LouAnn Jopp
Reviewed in 2020
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