Food Dehydration 101
Dehydrated Food Basics
Here’s everything you need to know to start dehydrating your own meals; the benefits of dehydrating food, what ingredients dehydrate the best, proper food handling procedures, the best way to store dehydrated food, along with recipes to inspire delicious dehydrated meals.
What Does it Mean to Dehydrate Food?
Through low heat and steady airflow, dehydration removes enough moisture from food through evaporation to inhibit the growth of bacteria, yeast, and mold. Dehydrating is one of the oldest methods of food preservation and has been used effectively since the dawn of civilization.
There are a number of different types of dehydrators and dehydrating techniques including air dehydration and oven dehydrating. I’m going to focus on using an electric food dehydrator.
Why Dehydrate food for camping, backpacking, hiking, or any type of travel?
You have control of your food and can create tasty menus by making your own meals, along with providing nutritionally sound fuel for your adventure. In addition, homemade dehydrated meals allow you to dramatically reduce the cost per meal compared to dining out.
Faster cooking times when all you have to do is rehydrate.
Gives you the ability to pack food without the need for a cooler, such as dehydrated fruit and hummus.
Weight and space savings are important, with dehydrated meals you free up a considerable amount of space.
Choosing a Dehydrator
Buying a food dehydrator can be overwhelming, there are so many options and price points. There are a few things you need to consider.
Make sure you have adjustable temperature settings, so you can choose the right temperature and safely dehydrate different types of ingredients. A dehydrator with an adjustable temperature setting is not intended to be used to speed up the dehydration process, it increases the risk of case hardening, explained below.
Make sure you choose a dehydrator with a programmable timer that will turn off the machine after a given amount of time. I like this so that I don’t over-dehydrate anything.
Fan position is important. Front-loading dehydrators have their fan and heating element in the back of the machine and will blow hot air across the trays for horizontal flow, which tends to be more efficient and results in more even drying. Stackable dehydrators have their fans and heating elements on the top or the bottom of the unit, which then blows air up or down for vertical air flow. This is less efficient and can result in uneven drying unless you reshuffle the order of the trays periodically. Stackable dehydrators are usually less expensive.
Capacity is important, so consider how much food you will be dehydrating.
Multi-purpose units are also available which is what I have. My Breville Smart Oven Pro gives me the ability to not only dehydrate, it also has 12 additional functions: Toast, Bagel, Bake, Roast, Broil, Pizza, Cookies, Proof, Air-Fry, Reheat, Warm, and Slow Cook.
Plant-Based Foods to Dehydrate
Fruits
Vegetables
Legumes like beans and lentils
Items such as hummus and stews
What Food Does NOT Dehydrate Well
There are a few food that should be avoided entirely for food safety or effectiveness reasons, such as:
Fats, fats do not evaporate therefore dehydrating will leave moisture in the food which can cause it to spoil or go rancid.
Nut butter is too high in fat to dehydrate, I recommend purchasing commercially available nut butter powders that have had the fats removed.
Avocados and olives, because they are too high in fat.
Store-bought condiments are not good candidates for dehydration.
Dehydration Temperatures
It’s important to dry food at the correct temperature. Too low of a temp could leave food in the “danger zone” for too long and risk bacterial growth. Too high and you risk case hardening. Case hardening occurs when the exterior of the food dries too quickly and forms a tough case around the outside, which then prevents the inside from properly dehydrating, trapping moisture inside which can cause mold and spoilage during storage. It’s always a good idea to check a few pieces by breaking them in half and seeing if any moisture presses out.
Here are the dehydration temperature guidelines:
95 F Herbs
125 F Vegetables
125 F Beans and Lentils
135 F Fruit
145 F Grains
As you can see there is quite a bit of variation in temperatures, which is why it’s important to make sure you’re grouping foods together appropriately, like when dehydrating full meals. If you want t speed up the dehydration process, you can either cut your food into thinner/smaller pieces or load less into your dehydrator.
Dehydrating Ingredients vs. Dehydrating Meals
You can dehydrate batches of single ingredients and assemble your meals later, or you can prepare a meal and then dehydrate the complete meal. The key to dehydrating complete meals is to make sure that all ingredients can be dehydrated at more or less the same temperature. Here are a few prepared recipes I have successfully dehydrated, more recipe inspiration further below.
How to Prepare Food and Equipment for Dehydrating
Cut everything into uniform pieces. One of the keys to even drying is to ensure that food is uniformly sized. Slicing with a mandoline will allow you to slice in uniform thickness and will make the task go much faster.
Pretreatment of fruits and vegetables can be done prior to dehydrating to retain color and flavor, improve dehydration time and texture, and increase shelf life. But NOT ALL vegetables require pretreatment.
Blanching or Steaming vegetables (dipping food in boiling hot water and then rapidly cooling in ice water) or steaming can help retain their color and can reduce rehydration time. This method is generally used for vegetables that are particularly tough or fibrous such as carrots, broccoli, celery, cauliflower, kale, green beans, potatoes, or sweet potatoes. Soft vegetables such as onions, garlic, mushrooms, bell peppers, spinach, and zucchini do not need to be steamed or blanched.
How to Dehydrate Vegetables
Most vegetables should be thinly sliced or chopped.1/8 inch thick or cut into even smaller pieces. Some veggies like corn, peas, and spinach don’t need to be cut.
Using frozen vegetables that have been thawed is a great time-saving hack since they are already cut and blanched for you. Just spread them out on your dehydrating trays and you’re all set to go.
Vegetables should be dehydrated at 125 F until dry and crisp. This will take anywhere from 4 hours to 12 plus hours depending on how thick you slice them, the type of dehydrator you’re using, the dehydrator load, the humidity in your house, etc. It is not possible to over-dehydrate vegetables when using the proper temperature, however, you can scorch them if dehydrated at too high of a temperature. It’s not that tough, once you play around with dehydrating your first batch you’ll get the hang of it.
How to Dehydrate Fruit
Dehydrated fruit is a great snack during the day or for adding to breakfasts such as oatmeal. Fruit can either be sliced thin (apples, bananas, strawberries, kiwi), cut into small pieces (pineapple, apples), left whole (raspberries, blueberries), or pureed and dried into fruit leather.
Thoroughly wash any fruits that will be dried with the skin on, as many have a waxy coating. Some fruits, like whole blueberries, grapes, and cherries, should be blanched in hot water followed by a quick ice bath, to crack the skin before dehydration.
Fruit should be dehydrated in a single layer with no overlapping at 135 F. Drying time will vary depending on the specific fruit. Apple slices may take as little as 6 hours, whereas whole blueberries and cherries could take multiple days.
Fruit is done dehydrating when it becomes leathery and is no longer sticky. Cut a few pieces in half and squeeze them-you shouldn’t be able to squeeze out any moisture.
Let the fruit cool and then condition before storing. See below on how to “Condition”.
How to Dehydrate Grains, Legumes, Pasta, and Rice
Grains and Rice: Cook as usual in water or non-fat vegetable stock. Rice will rehydrate best if cooked al dente. Dehydrate at 145 F for 6-12 hours, until completely hard and dry. Dehydrating rice and grains at a lower temperature can cause a type of bacteria that thrives on cooked rice.
Beans and Lentils: Canned beans will dehydrate and rehydrate best, though home-pressure cooked beans also work. Lentils can be cooked on the stovetop until tender, or you can use canned lentils. Dehydrate at 125 F until hard and crunchy, 6-12 hours. Beans do have a tendency to split while they are rehydrating, this has never bothered me, plus it allows the beans to rehydrate faster than if they remained whole.
Pasta: Some pasta shapes work better than others to dehydrate and rehydrate. I honestly stick to thin pasta such as vermicelli noodles or buckwheat soba noodles so dehydrating isn’t even necessary as they rehydrate quickly in hot water. I wouldn’t spend the time dehydrating and rehydrating pasta unless, of course, it’s in a prepared casserole-type dish.
How to Safely Store Dehydrated Food
After you’ve dehydrated your food you’ll want to store it in a cool dry place.
How Long Does Dehydrated Food Last
Most home-dehydrated food, when prepared and stored properly, can last for months and up to a year. A lot depends on what you store it in and the storage environment.
Conditioning
Conditioning is an important final step, primarily for dehydrated fruits, before packing them away for storage. In fruit, the remaining moisture may not be distributed equally among the pieces so they risk growing mold.
To condition, cool the dried fruit to room temperature and store it loosely in a clear, airtight non-plastic container such as a large glass jar. Let it sit for a week, checking it daily for any signs of moisture or condensation. If you see any, put the fruit back into the dehydrator to dry linger. If you see any mold growth during this time, toss the entire batch. Shake the jar each day to keep the fruit from sticking together, potentially creating moisture pockets. After a week if there are no signs of moisture or mold, you can package and store the fruit using one of the methods below.
you do not need to condition vegetables, as much more of the moisture is removed during the dehydrating process and it’s easier to tell if they’re fully dried. But it doesn’t hurt if you feel it’s something you want to do.
Storage Methods and Considerations
There are environmental factors that affect the shelf life of dehydrated foods.
Temperature: Even when properly dried and sealed, the temperature will still affect the shelf life of your food.
Moisture: The point of dehydrating is to remove moisture so you want to safely store your food without spoiling it, so that’s the last thing you want to do is to re-introduce moisture to the storage process!
Oxygen: Oxidation will cause your food to break down, lose flavor, and shorten the shelf life.
Light: Like oxygen, light will break down the food and cause off-flavors, loss of nutrients, and shortening the shelf life.
The Solutions: Store dehydrated food in airtight containers in a cool, dry, dark place with good ventilation. Let the food cool completely before transferring to a storage container, this will help prevent condensation. Sanitize your hands and containers before handling food for storage and make sure everything is completely dry.
If you’re making food for a trip that’s coming up in the next week or two, you can store it in ziplock bags in the refrigerator. Make sure you let the food come to room temperature before opening the bag to prevent introducing moisture to the condensation. This method is NOT suitable for long-term storage since these types of bags are not truly airtight. In the case of long-term storage use vacuum sealed storage bags.
How to Rehydrate Dehydrated Food
Rehydration is a factor of water, heat, and time. You want to add as much water back into the food as you took out in the dehydration process. You can do this by weighing food before it goes into the dehydrator, then subtracting the dehydrated weight, and that number is the amount of water you want to add back in. Or if you’re like me, you just wing it. My meals typically require 1 to 1 1/2 cups of hot water to rehydrate.
There are three methods for cooking rehydrated meals:
Soak & Simmer: This is the fastest method but uses the most fuel if you’re using a non-electric fuel source. Add your meal and water to your pot and let it soak a bit. Then simmer the meal until it has rehydrated. Lower the heat toward the end to prevent scorching.
Soak, Simmer & Set: This method takes a bit longer but uses far less fuel than the previous method. It’s a great option for hiking, backpacking, and driving after breakfast where you want lunch ready when you stop for a rest break. Same as above; add your meal and water to your pot and let it soak a bit, then cover and bring the meal and water to a rapid simmer for a few minutes before turning off the heat. Let the meal rehydrate, stirring after 10 minutes. You can reheat if it has cooled too much once it’s rehydrated or you can be a champ like us backpackers and eat it lukewarm. With this method you can have your dehydrated meal in a freezer bag, add the water and let it soak until you’re ready to eat, you might like to place it in an insulated bag or pouch to keep it warm.
Recipe Inspiration
Breakfasts
Rolled oats with cinnamon, ground flax, chia seeds, walnuts, and dehydrated fruit
Rolled oats with savory flavors like poultry seasoning, sage, walnuts, and dehydrated, celery, onions, and kale.
Lunch and Dinner
You can assemble individual meals by adding ingredients to a Ziplock FREEZER Bag:
Basic Vegetable soup or stew: Vegetable powder, Mrs. Dash, onion powder garlic powder, instant brown rice, buckwheat soba noodles, or couscous, and dehydrated vegetables of your choosing.
Indian Inspried Curry: Vegetable powder, Mrs. Dash, onion powder garlic powder, instant brown rice, buckwheat soba noodles, or couscous, and dehydrated vegetables of your choosing, add cashew powder and curry powder.
Chili: Vegetable powder, chili powder, smoked paprika, onion powder garlic powder, dehydrated black beans or kidney beans, and dehydrated vegetables of your choosing.
Prepared Meals That Dehydrate Well:
Snacks
Dehydrated pineapple strips
Rehydrated Hummus on whole-grain crackers or wraps
Whole-grain wrap, rehydrated store-bought peanut butter powder, rehydrated bananas, non-dairy chocolate chips, golden raisins