How to Freeze Dry Food

How to Freeze Dry Food

Freeze drying is a fascinating and effective method for preserving food, extending its shelf life while retaining its taste and nutritional value. In this comprehensive guide, we'll delve deep into the world of freeze-drying, covering everything from its scientific principles to the practical steps you can take to freeze-dry food at home.

What Is Freeze Drying?

Freeze drying, also known as lyophilization, is a specialized food preservation technique that involves removing moisture from food items at extremely low temperatures. The process starts by freezing the food, followed by placing it in a vacuum chamber where the frozen water content sublimates, transforming from ice directly into vapor without passing through a liquid phase. This results in food that is lightweight, compact, and has a long shelf life.

Are Freeze-Dried Foods Healthy?

Now that we understand the basics of freeze drying, let's explore the health aspects. Freeze-dried foods offer several health benefits:

Nutrient Retention

Freeze-drying preserves the majority of the food's nutrients, including vitamins, minerals, and antioxidants. This means that freeze-dried fruits and vegetables can provide the same nutritional value as their fresh counterparts.

Longer Shelf Life

One of the primary advantages of freeze-dried foods is their extended shelf life. Properly stored, freeze-dried items can last for years without significant loss of quality or nutritional value. This makes them a valuable addition to emergency food supplies.

Reduced Additives

Many commercially freeze-dried foods contain minimal additives or preservatives compared to other processed foods. This makes them a healthier option for those looking to reduce their intake of artificial ingredients.


Freeze-dried foods are lightweight and easy to store, making them convenient for outdoor activities like camping and hiking. They're also popular in space exploration due to their long shelf life and minimal storage requirements.

However, it's important to note that not all freeze-dried foods are created equal. The health benefits depend on the quality of the initial food product and the specific freeze-drying process used. Some freeze-dried foods may contain added sugars, salt, or other ingredients, so it's essential to read labels when purchasing commercial freeze-dried products.

Peaches,cherries, peppers, and carrots stacked next to one another on a striped towel.

Foods That Can Be Freeze-Dried

While freeze-drying is a versatile preservation method, not all foods are equally suitable for the process. Here are some foods that are commonly freeze-dried:


  • Berries: Strawberries, blueberries, raspberries, and blackberries are frequently freeze-dried to create delicious and nutritious snacks.
  • Apples: Freeze-dried apple slices are a popular choice for their sweet and crispy texture.
  • Bananas: Freeze-dried banana chips are a healthy alternative to traditional fried chips.


  • Peas: Freeze-dried peas retain their vibrant green color and are often used in soups and salads.
  • Corn: Freeze-dried corn can be used in various dishes, including casseroles and salsa.
  • Carrots: Carrot chips make for a crunchy and nutritious snack.

Dairy Products

  • Milk: Freeze-dried milk can be rehydrated and used as a dairy source in recipes.
  • Cheese: Some types of cheese can be freeze-dried for use in emergency food kits.

Meat and Poultry

  • Chicken and Beef: Freeze-dried meat is a valuable source of protein for camping and survival situations.
  • Fish: Certain types of fish can be freeze-dried for longer storage.

These are just a few examples of foods that can be freeze-dried, but the possibilities are vast. Freeze-drying can also be applied to entire meals, such as pasta dishes, soups, and stews. The choice of food items largely depends on personal preference and intended use.

Preparing Food for Freeze-Drying

Properly preparing your food for freeze-drying is essential to achieve the best results, regardless of the method you choose. Here are some steps to follow:


Start by thoroughly washing and cleaning your fruits, vegetables, or other food items. Removing dirt, pesticides, and contaminants ensures a safe and high-quality final product.

Cutting and Slicing

Uniformly cut or slice your food into pieces of similar size. This helps ensure even drying and prevents some pieces from becoming overly dry or under-dried.


Blanching involves briefly immersing your food items in boiling water, followed by a quick cool-down in ice water. This step is optional but can help preserve color, texture, and flavor in certain foods.

Arrange on Trays

If using a freeze dryer, arrange your prepared food items on the trays provided. Ensure that there is enough space between items to allow for proper airflow and even drying.

How to Freeze Dry Foods in a Freeze-Dryer

If you have access to a dedicated freeze dryer, you can enjoy the convenience and precision it offers for freeze-drying food. Here's a step-by-step guide:

Step 1: Load the Freeze Dryer

Place your prepared food items on the trays or shelves inside the freeze dryer. Be sure not to overcrowd the trays, as adequate space between items is essential for efficient drying.

Step 2: Set Parameters

Follow the manufacturer's instructions for your specific freeze-dryer model to set the appropriate parameters. This typically includes selecting the freeze-drying time and temperature.

Step 3: Start the Freeze Dryer

Once the parameters are set, start the freeze dryer. The machine will begin the freeze-drying process, which can take several hours to complete, depending on the quantity and type of food being processed.

Step 4: Monitor Progress

Keep an eye on the freeze dryer throughout the process to ensure everything is running smoothly. Some freeze dryers have built-in sensors to detect the moisture content of the food, which can help determine when it's ready.

Step 5: Remove and Store

Once the freeze-drying process is complete, carefully remove the trays or shelves from the machine. Your freeze-dried food should now be lightweight, crispy, and free of moisture. Transfer it to airtight containers or vacuum-sealed bags for long-term storage.

How to Freeze-Dry Food in a Freezer

If you don't have access to a dedicated freeze dryer, you can still freeze dry food using your home freezer. While this method may not yield the same level of quality and longevity as commercial freeze drying, it can be a practical alternative. Here's how to do it:

Step 1: Prepare the Food

Clean, cut, and arrange your food items on a baking sheet or tray. Ensure they are spaced apart to allow for proper freezing.

Step 2: Pre-Freeze

Place the tray with the food items in your home freezer and let them pre-freeze for several hours or overnight. Pre-freezing helps in removing some of the moisture from the food.

Step 3: Transfer to Airtight Containers

Once the food items are pre-frozen, transfer them to airtight containers or vacuum-sealed bags. Make sure to remove as much air as possible to prevent freezer burn.

Step 4: Return to the Freezer

Put the containers or bags back into the freezer. Over the next few days or weeks, the remaining moisture in the food will gradually sublimate and be absorbed by any absorbent material you have added to the container.

Step 5: Monitor and Test

Check the progress of your freeze-drying process periodically. The time required for freeze drying in a regular freezer can vary depending on the food item and its thickness. Some items may take a few weeks to fully dry.

Step 6: Store Properly

Once your food is freeze-dried, store it in airtight containers or vacuum-sealed bags in a cool, dark place to maintain its quality.

How to Freeze-Dry Food With Dry Ice

Another method for freeze-drying at home involves using dry ice. This approach is suitable for smaller quantities of food and can yield good results. Here's how to do it:

Step 1: Gather Supplies

You'll need dry ice, a container with a lid, a rack or mesh to elevate the food, and the food items you want to freeze dry.

Step 2: Prepare the Food

Clean and cut your food items into uniform pieces, just as you would for other freeze-drying methods.

Step 3: Create the Setup

Place the rack or mesh inside the container, elevating it above the bottom. This allows the sublimated moisture to fall to the bottom of the container, away from the food.

Step 4: Add Dry Ice

Place a layer of dry ice at the bottom of the container, ensuring there's enough space for the food to be placed above it.

Step 5: Arrange the Food

Place your prepared food items on the rack or mesh inside the container. Ensure they are not touching each other to allow for proper airflow.

Step 6: Seal the Container

Tightly seal the container with the lid, but leave a small gap to allow excess gas to escape as the dry ice sublimates. This is essential for creating a vacuum environment.

Step 7: Monitor and Wait

Leave the container undisturbed in a well-ventilated area, ideally at room temperature. As the dry ice sublimates, it will create a vacuum, drawing out the moisture from the food.

Step 8: Store Properly

Once the dry ice has completely sublimated and the food is dry to the touch, remove the food from the container and store it in airtight containers or vacuum-sealed bags in a cool, dark place.

How to Freeze-Dry Food in a Vacuum Chamber

For those looking for an alternative method of freeze-drying without specialized equipment, a vacuum chamber can be used. Here's how to freeze-dry food using this approach:

Step 1: Prepare the Food

Clean and cut your food items into uniform pieces, just as you would for other freeze-drying methods.

Step 2: Arrange the Food

Place your prepared food items on a tray or rack that can fit inside the vacuum chamber. Ensure they are spaced apart for even drying.

Step 3: Create a Vacuum Environment

Place the tray or rack with the food inside the vacuum chamber. Seal the chamber and begin the vacuuming process. The reduced pressure will cause the moisture in the food to evaporate.

Step 4: Monitor and Wait

As the vacuum chamber removes moisture from the food, you'll need to monitor the process. Depending on the food and the vacuum chamber's capabilities, this can take several hours to days.

Step 5: Store Properly

Once the food is dry to the touch and moisture has been removed, remove it from the vacuum chamber and store it in airtight containers or vacuum-sealed bags in a cool, dark place.

Various fruits in bowls and on trays next to glass jars on a wooden surface.

Explore the Art of Freeze Drying Food Today 

Freeze drying is a versatile and effective method for preserving food, whether you're looking to extend the shelf life of your favorite ingredients, create convenient snacks for outdoor adventures, or prepare for emergency situations. Understanding the science behind freeze drying, its health benefits, and the various methods available for both commercial and home use can empower you to make the most of this innovative food preservation technique.

By following the steps outlined in this guide, you can experiment with freeze-drying at home, explore different methods, and enjoy the benefits of long-lasting, nutrient-rich foods. Whether you're a culinary enthusiast, a prepper, or simply curious about the science of food preservation, freeze-drying opens up a world of possibilities in your kitchen. You'll be able to create delicious and lightweight backpacking meals, extend the shelf life of seasonal fruits and vegetables, and even indulge in freeze-dried desserts. Moreover, you'll gain a deeper understanding of the fascinating process of freeze-drying and its applications beyond the culinary realm. So, roll up your sleeves, gather your ingredients, and embark on a journey of culinary discovery with freeze-drying as your trusted companion.

Check out our SweetyTreaty Co. blog today to learn more about our delicious freeze-dried candy, which is available online!