Drying food

Marilyn Herman

Dry foods in the oven or a food dehydrator by using the right combination of warmth, low humidity and air currents. Sun drying is not recommended in Minnesota due to high humidity and cool night temperatures. In drying, a warm temperature allows the moisture to evaporate. Air currents speed up drying. Low humidity allows moisture to move from the food to the air.

Preparing food to dry

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 one-half teaspoon Vitamin C (ascorbic acid) per quart of cold water. Dip fruit for one minute, then drain and put on rack to begin drying.

Drying takes time

Drying food is a slow process. In a dehydrator, it takes six or more hours to dry foods. In the oven, it takes eight or more hours. Drying time depends on the type of food, the thickness of the cut, the moisture content of the food and 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 minutes to one hour cooling time. Too long a cooling period allows moisture from the air to re-enter the food.

Storing dried food

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. Heavy-duty plastic bags with press-together seals are acceptable, but are not insect- or rodent-proof. Screw lids or covers on glass jars to prevent insect contamination, but it is not necessary to heat-process the jars.

Check containers within seven to 10 days to see if moisture is present. If you see moisture, remove food and redry at 140 to 160 degrees Fahrenheit. If food is moldy, discard it, throw away the plastic freezer bag or sterilize the jar.

Shelf life of dried food

Dried foods keep four months to one year depending on storage conditions. Store in cool, dry, dark areas. For best quality, store under 60 degrees Fahrenheit. 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 food

Dried fruits can be eaten as nutritious snacks, or can be soaked in water or juice for one to two hours and used in favorite recipes. Sliced vegetables can be eaten dried as tasty vegetable chips for dips. Most vegetables are refreshed with water before use. The water can be added back to vegetables by soaking in tap water for one to two hours. Use two cups of water for each cup of dried food. Using boiling water speeds up the soaking period. Dried vegetables can be added directly to soups or stews without pre-soaking, drawing on the liquid in the soup or stew for rehydration during cooking.

Related resources

Revised by Suzanne Driessen 2016

Drying