University of Minnesota Extension
www.extension.umn.edu
612-624-1222
Menu Menu

Extension > Food > Food Safety > Preserving and Preparing > Drying > Drying Food

fresh and dried green beans

Drying

Drying Food

Marilyn Herman, Extension Educator — Food Safety

Reviewed 2012 by Suzanne Driessen, Extension Educator — Food Safety.

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

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.

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.

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.

Although it is not necessary to store
dried food in a refrigerator or freezer,
except for meat jerky, low temperatures
extend the shelf life.

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.

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.

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

  • © 2014 Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy