How to Dehydrate Vegetables for Your Winter Soups and More

A bowl of dehydrated vegetables surrounded by fresh vegetables

That generous bounty of fresh vegetables harvested from your garden won't last forever. Learn how to dehydrate vegetables, a simple and affordable way to extend the life of your yield and fill your larder for the winter. Properly dehydrated vegetables will keep in the pantry for six months to a year.

Think dried peppers to spice up homemade soups, stews and casseroles; sun-dried tomatoes in pasta sauces and to top off pizzas; or dried veggies and vegetable leathers for healthy backpacking meals and lunchbox snacks.

Benefits of Dehydrating Vegetables

One of the oldest and easiest methods of food preservation, dehydrating preserves foods by removing moisture to prevent decay and spoilage.

Drying vegetables requires some prep but much less than canning or freezing. They don't take up valuable freezer or shelf space and are way more economical than those store-bought bags of designer kale chips!

A Variety of Vegetables Can Be Dehydrated

Dried vegetables are a good source of minerals and B vitamins. Experiment dehydrating peppers, summer squash, celery, okra, mushrooms (OK, not technically a vegetable), green beans, onions, peas, corn and tomatoes (technically a fruit.) Root vegetables like carrots will keep well for several months in a cool, dry basement or cellar but can also be dehydrated. Dried herbs, such as oregano, basil, parsley, dill, fennel, lemon balm and mint, are great for baking, cooking and teas.

Prep Your Vegetables Before Dehydrating

As dehydrating concentrates the flavor of vegetables, it's best to use fresh, peak-season produce. Although peeling is optional, the skin reduces surface area and prevents moisture from escaping. To dry them quickly and evenly, slice vegetables into pieces of the same size, shape and thickness.

Blanch Most Vegetables Before Drying

Blanching the vegetables in a solution of 1/4 teaspoon of citric acid per quart of water helps destroy potentially harmful microorganisms and slows enzyme activity that can change the flavor and texture of dried veggies during storage. The heat jump-starts the drying process by softening the cell structure, allowing moisture to escape so pieces will dry more quickly and rehydrate faster when you're ready to use them. After blanching, drain the vegetables well before placing them on dryer trays or baking sheets.

The Colorado State Cooperative Extension offers an excellent reference chart listing blanching and drying times, as well as dryness tests for different vegetables. Blanch asparagus, spinach and kale for four to five minutes, and dry for six to 10 hours. Asparagus is done when its texture is leathery to brittle, and spinach and kale are done when they're crisp.

Tomatoes don't require blanching. Instead, steam or dip them in boiling water to loosen the skins, and then chill in cold water. Peel and slice 1/2 inch thick or cut into 3/4 inch sections and dip them in a solution of 1 teaspoon of citric acid to a quart of water for 10 minutes. Dehydrate the tomatoes for six to 24 hours.

How to Dehydrate Vegetables

Proper dehydrating requires the right combination of low heat and humidity with adequate air circulation. Thermostatically controlled electric dehydrators are generally the method of choice. They're easy to use and fast because their built-in fans circulate air. Oven drying works as well but takes longer. (Convection ovens also have fans, so they too dry veggies faster than conventional ovens.)

Oven Drying

Place sliced vegetables on a baking sheet lined with parchment paper without allowing the pieces to touch or overlap. Preheat to the lowest setting (140 to 150 F), leaving the oven door open 2 to 3 inches to allow moisture to escape. Monitor the temperature with an oven thermometer placed directly on the racks. Leave at least 3 inches of clearance at the top and bottom of the oven, with 2 1/2 inches between trays. Then, shift trays top to bottom and front to back every 30 minutes.

Sun Drying

An ancient method, sun drying works in dry climates with a minimum temperature of 86 degrees, with less than 60% humidity. This method isn't recommended in areas with higher humidity, as the vegetables can quickly become moldy in the moist air.

Air Drying

Drying at room temperature requires adequate heat, humidity and air circulation. Most air-conditioned homes will likely be too cool to dry foods quickly enough to avoid spoilage.

How to Store Dried Vegetables

The National Center for Home Food Preservation advises drying vegetables until they're brittle or crisp and cooling them completely before transferring them to clean, airtight freezer containers with tight-fitting lids, canning jars or plastic freezer bags. Store them in a cool, dark place, and check them frequently for moisture. If you detect any moisture but the veggies aren't spoiled, use them immediately or redry and repackage them.

Each time a container is opened, the food is exposed to air and moisture that can cause spoilage. Consider packing single-use portions of dehydrated vegetables or place the specific amounts called for in your favorite recipes.

Cooking With Dehydrated Veggies

Many dried vegetables are great to enjoy just as they are, while others, like mushrooms, are better rehydrated or "refreshed" for use in soups, stews and sauces. For most uses, dehydrated vegetables need refreshing by either soaking in water or cooking, which will return them to their original shape.

The amount of water and the length of time required to refresh 1 cup of dehydrated vegetables varies according to the vegetable, as the University of Missouri Extension outlines. Properly pretreated vegetables will need a minimum of refreshing. Rehydrate spinach, kale, cabbage, chard or tomatoes by covering with hot water and simmering to the desired tenderness. Soak root, stem and seed vegetables 30 minutes to one-and-a-half hours in cold water before cooking.

Susan Mills-Gray, a state nutrition specialist at the University of Missouri Extension, shares this easy vegetable soup recipe:

Vegetable Soup

Ingredients:

  • 4 cups water
  • 3/4 to 1 cup dried vegetables
  • 4 cubes beef bullion
  • Seasonings to taste (herbs, curry, etc.)

Instructions:

  • Bring water to a boil.
  • Add dried vegetables, bouillon and seasonings.
  • Simmer for about 20 minutes or until vegetables are tender, though chewy.

Check out Burpee's vegetable selection for more winter soup ingredients.

Written by Robin Plaskoff Horton, Urban Gardens

Robin Horton is a home and garden writer and publisher of the award-winning and Webby-nominated design, lifestyle and travel blog, Urban Gardens.

October 11, 2021
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