Want to dehydrate vegetables for your hikes?
Dehydrating vegetables for hiking can add a great deal of nutrition to your meals. Drying is a long-standing, fairly easy method of food preservation. Whenever you preserve foods, choose the best-quality fruits and vegetables. As with other food preservation methods, drying does not improve food quality. Proper and successful drying produces safe food with good flavor, texture, color and nutritional properties.
The following vegetables are rated as “excellent” or “good” for their quality after drying:
- sweet corn
- peppers (all types)
Many other vegetables may be dried, but the quality of the end product may not be as good as those listed. Tomatoes, for example, tend to absorb moisture easily, which can lead to color and flavor changes.
Preparing Vegetables for Dehydration
Prepare vegetables for preservation immediately after picking to prevent color, flavor, texture, sugar content and nutrient changes. Sort and discard any food with decay, bruises or mold. Thoroughly rinse vegetables with running water, using a produce brush if necessary, then drain the vegetables well. Cut foods into c-inch to 6mm slices. The higher the water content, the larger the slice size should be. Small slices of high-moisture foods would nearly disappear when all the moisture has evaporated.
To preserve quality and color, blanch prepared vegetables in boiling water or a citric acid solution. Blanching is a heating process that destroys enzymes, which can cause color and flavor issues. Water blanching achieves a more even heat penetration than steam blanching or microwave blanching. Citric acid acts as an anti-darkening and anti-microbial agent.
If using citric acid (available in your supermarket), stir ¼ teaspoon of citric acid into 3 cups of water. Citric acid helps prevent discoloration and acts as an anti-microbial agent.
- Fill a large kettle one-half to two-thirds full of water. Bring the water to a rolling boil.
- Place the vegetables in a wire basket, colander or mesh bag. You can blanch up to 3 cups of vegetables at a time.
- Submerge the vegetables in the boiling water, making sure the water covers the vegetables.
- As soon as the water reboils, start timing. Adjust the heat to ensure continuous boiling.
- Submerge the container with the vegetables in cold water for the same amount of time as the blanching time).
- Drain the vegetables on paper towels.
Drying is not a precise method of food preservation, and the amount of drying time will vary depending on the equipment, moisture content of the vegetables and the humidity in the air.
Spray a cookie sheet or similar flat tray with vegetable spray, or line the tray with plastic wrap or parchment paper and spray with vegetable spray. Another option is to use the specially designed plastic sheets for electric dehydrators, and follow the manufacturer’s directions.
Oven drying: Test your oven to be sure it can maintain a low enough temperature; otherwise, “case hardening” may occur. This is the formation of a “crust” on the food, which prevents the interior from drying properly.
To test your oven, set it to the lowest setting. Place an oven-safe thermometer on the rack where food will be placed. Leave the oven door open 50 to 150 mm. Place a fan near the open door to circulate air. Check the temperature. If your oven can maintain a low enough temperature (60 to 65 C), it may be used for food dehydration. Racks should be 50 mm apart, with at least 75 mm of clearance from the top or bottom to the rack.
Note: Oven drying is not a safe procedure to follow if young children are present.
Food dehydrator drying: Follow the manufacturer’s directions.
Testing for Dryness
Allow vegetables to cool prior to testing for dryness. Fully dried vegetables should be brittle or “crisp.”
Packaging and Storing
Pack cooled dried vegetables in small amounts in dry glass jars (preferably with dark glass) or in moisture- and vapor-proof freezer containers, boxes or bags. Metal cans may be used if food is placed in a freezer bag first. Properly stored, dried vegetables keep well for six to 12 months. Discard all foods that develop off-odors or flavors or show signs of mold.
Using Dried Vegetables
Dried vegetables can be used in soups, dips, stews and sauces. When reconstituted, 1 cup of dried vegetables becomes 2 cups. When reconstituting leafy greens (kale, spinach), cover the dried vegetables with hot water and simmer to desired tenderness. When reconstituting root or seed vegetables (beans, corn, carrots), cover with cold water and soak for about an hour, then simmer until tender and use as desired.
Food Preservation: Drying Vegetables
North Dakota State University
Julie Garden-Robinson, Ph.D., R.D., L.R.D., Food and Nutrition Specialist