Methods for drying food at home
Revised by author, 2011. Peer reviewed by Suzanne Driessen, Extension Educator, University of Minnesota Extension, 2012.
Introduction to drying food at home
Drying or “dehydrating” food is a method of food preservation that removes enough moisture from the food so bacteria, yeast and molds cannot grow.
To dry foods successfully you need:
- Low humidity
- A source of low heató120 degrees F to 150 degrees F
- Air circulation
- 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.
- Takes two to three times longer to dry food in an oven than in a dehydrator; the oven is not as efficient and uses a great deal more energy than a dehydrator.
- Drying in an oven is slower than in a dehydrator because ovens do not have built-in fans for the air movement.
- To use your oven, check the oven dial to see if it has a reading as low as 140 degrees F. If the thermostat does not go this low, your food will cook instead of dry.
- Leave the oven door propped open 2 to 4 inches and place a fan near the outside of the oven door to improve air circulation.
- An oven thermometer placed near the food gives an accurate reading of the drying temperature.
- 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.
- 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 is not recommended in Minnesota due to our high humidity and cool night temperatures.
- 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.
- 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 to 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.