If there’s one thing that I absolutely love, it’s freeze-dried goodies. Lyophilization, otherwise known as freeze-drying, not only preserves the color of food but also preserves the flavor. Freeze-drying reduces thermal damage to nutrients that are heat sensitive. But how do you freeze-dry and store foods?
Freeze-drying food is a straightforward process. Prep food to be freeze-dried and pre-freeze it on trays. Put the trays into the freeze-dryer and run them for 24 to 48 hours. Test the food to make sure it is done. Store it in a cool, dry place in an air-tight container with an oxygen absorber.
Despite how straightforward freeze-drying is, there are still a couple of things you need to have in mind to ensure the process goes smoothly. In the guide below we will give detailed tips on how to successfully freeze-dry, package and store your favorite foods.
How to Freeze-Dry Your Favorite Foods
In 5 simple steps, you can freeze-dry a large number of meats, vegetables, fruits, cooked meals, and even drinks. It’s not the only preservation method but it’s by far the best. Here’s a general guide on how to freeze-dried food.
Step #1: Prepare your food for freeze-drying
It’s important to know that freeze-drying doesn’t kill most bacteria or viruses – it renders these pathogens dormant. While it’s difficult to get rid of all the microbial activity going on in food, it can at least be lowered significantly by adequately preparing each food item before freeze-drying.
Want to know if Does Freeze-Drying Foods Kill It? (Bacteria, Virus, Nutrients, Enzymes)? Read that article so I can give you the answers!
Adequate food preparation for freeze-drying entails washing the food items, cutting them up into uniform pieces, and letting them dry before freezing.
Here are a couple of pointers that will help you successfully navigate this step:
Tip #1: Wash your food.
Using water to wash the fruits and vegetables is just as efficient as using vegetable and fruit washes.
Vinegar, salt, and baking soda have also been shown to help reduce bacteria and do a great job at removing residue and surface dirt on fresh produce.
Tip #2: Cut food into small pieces
To avoid cold spots and uneven drying time, cut large food products into uniform pieces.
The food will also need to be no more than about 1 to 1 ½ inches thick, or it won’t fit into the freeze-dryer. The trays do get packed in pretty well!
Tip #3: Make airflow in the freeze-dryer easy
Tough skins and rinds don’t freeze-dry as easily. The best way to handle it is to remove the rind or peel.
However, if you want to keep the peel intact (especially if the rind is important for storage and flavor in the future) then you’ll need to maximize airflow by cutting smaller pieces. You’ll also want to poke holes in the rinds or peels.
Tip #4: Remove excess water
Make sure to dry each food item with a paper towel or clean cloth to further reduce bacterial activity and to ensure that they pre-freeze properly. A salad spinner can be used to remove excess moisture from food items, or it can be placed on a cookie sheet to dry.
Step #2: Prepare your freeze-dryer for use (and pre-freeze the food)
Now you’re ready to freeze-dry. If you prepared the food already (as we outlined in step 1), then you’re mostly already there. You’ll need to load your food onto trays and store it until the freeze-dryer is ready to go.
If you’re an expert at perfectly timing things, then you can put the trays directly into the freeze-dryer.
However, most of us already have a load going in the freeze-dryer, so we put some plastic wrap on the trays and put them in the freezer until the freeze-dryer is available.
Pre-freezing foods like this have three advantages.
- It means you can process more foods quickly while the freeze-dryer is running.
- It also shortens the overall freeze-drying time, as the foods are frozen and don’t have to be frozen by the freeze-dryer. You do, however, have to put the food into the freeze-dryer when it’s frozen, or you risk thawing your food.
- Because you’re using frozen foods, you lower the risk of food-borne illnesses because you’re controlling food temperature and keeping it out of the “danger zone” where bacteria thrive.
Food items can be frozen as they are or prepared into smaller pieces before pre-freezing. A freeze-dryer-sized tray or cookie sheet is great for this process; all that needs to be done is to place the food items on the tray, and then store them in the freezer until they are ready to freeze-dry.
While the food freezes, proceed with preparing the freeze-dryer. It’s important that the freeze-dryer runs for a few hours before you make use of it. Make sure it is completely frozen.
Putting food into the freeze-dryer before it reaches the correct temperature can create a risk for bacterial growth. Although freeze-drying renders bacteria and viruses dormant, microbial activity growing on the food before the preservation process can shorten the overall shelf life.
Step #3: Proceed to freeze-dry
Now you’re ready to freeze-dry!
- If you’re pre-freezing foods, you’ll need to start your freeze dryer so that it’s on a deep freeze before you pause it to add the food.
- If you’re adding fresh food, you can add it right when you start the freeze dryer. The downside to this method is that the food then is in the “danger zone” where bacteria thrive and it may increase the risk of food-borne illnesses.
If the food wasn’t’ already on the freeze-dryer trays, it can be transferred to a freeze-dryer-sized tray or cookie sheet any time before you put the trays in the freeze-dryer.
Note: the freeze-dryers use a special-sized stainless-steel tray, so a regular-sized half-sheet cookie tray won’t work in the freeze-dryer. We have two sets so we can pre-freeze the next load while we’ve got the current load running.
Avoid arranging food unevenly or stacking it too deeply on the trays, as this will make the food dry unevenly.
If there is no other choice than to layer, make sure to use breathable mats to separate each tier. Another alternative is to make use of the trays from the freeze-dryer, using liners so there is no sticking.
Set your freeze dryer’s controls to the correct setting for the food, based on your software and version of the freeze-dryer. You can find recommended settings and control times in your user manual.
After doing this, let the freeze-dryer run and check on it from time to time. Don’t open the door to check! Just make sure the thing is still running.
I like to time my freeze dryer’s run schedule so that it will finish its run during daytime hours. I don’t want to get up at 2:15 AM to pull a load out and store it ever again.
It’s a good idea to set an alarm as well. That way, you don’t forget it in the freeze-dryer for too long, either.
- It should take about 24 hours to thoroughly freeze-dry thinly cut food items.
- It should take 36 to 48 hours to properly freeze-dry food items that are not so dry (or are naturally moist, like fruit) or are in large slices.
Pro tip: Set the freeze-dryer to end on a warm cycle. This way, when it’s time to take your food out of the freeze-dryer, it’s from room temperature to slightly warm. This prevents condensation from attaching to freeze-dried foods, which can ruin them.
Warm freeze-dried food doesn’t absorb as much moisture as cold freeze-dried food. This means that the warm freeze-dried food will last longer.
Step #4: Evaluate the end product to see if it’s properly freeze-dried
Evaluate the freeze-dried foods to ensure that they are well preserved. Properly freeze-dried food should be completely brittle and have no cold or visibly wet spots.
If the food isn’t done, put it back in the freeze-dryer and set the controls to run for another cycle or two. When it’s done again, be sure to re-check it.
Pro tip: I recommend you snap open at least one piece of food per tray just in case the trays freeze-dried unevenly.
Once you know that the food is properly freeze-dried, transfer the freeze-dried food to a gallon-sized Ziploc immediately – don’t store them in a mylar bag just yet.
- When closing the Ziploc bag, get as much air out as possible.
If there is water in the bag, then your food is not properly freeze-dried. It will need to be eaten right away or run through another cycle, but the overall shelf-life of this food will be shorter.
On the other hand, if there’s no moisture in the plastic bag, then the food was properly freeze-dried and can be stored in a mylar bag. It’s safe to store for the long term.
Pro tip and Note: Freeze-dried foods that passed this test will last considerably longer than freeze-dried foods that failed and had to be put through another cycle.
Step #5: Package the freeze-dried food item and store it
Now that the food has been successfully freeze-dried and tested for moisture, it’s time to move to the next step: packaging your freeze-dried food for long-term storage.
There are several ways to go about this step; some people prefer to vacuum seal their food into mason jars, while others prefer to use a mylar bag.
Both ways work well, but keep the following pointers in mind if choosing the mason jars:
- If there is not much storage space in your pantry, then mason jars might not be the best option.
- Too much light can affect the contents of a mason jar, so make sure to store it in a cool and dark place with light controls.
- Make sure to package your freeze-dried food into mason jars with oxygen absorbers before vacuum sealing the jar.
Mylar bags are pretty straightforward to use – all that needs to be done is to store the freeze-dried food in the bags with oxygen absorbers. An impact sealer (that comes with the freeze-dryer) can then be used to seal them closed. We like to seal them twice in case one seal fails.
Labeling the storage containers or packages with the type of contents and the date they were stored is a really important step. Doing this makes locating them easier and helps ensure that each food item is consumed within the proper time frame.
We like to include both the storage date and a self-recommended “eat by” date. We know it’s a recommendation rather than a rule, but it does help us rotate our pantry reliably.
Want to know more about storing food in mason jars? Read my new article, How to Safely Store Freeze-dried Foods in Mason Jars (vacuum sealer), where I’ll show you how to vacuum-seal them so your freeze-dried foods stay good the whole shelf life.
How Do You Freeze-dry Food at Home? Can You do it Without A Machine?
A freeze-dryer must be used for freeze-dried food. There is no hack or alternative process that can be done with food that will provide the same results as a freeze-dryer. However, there are many other preservation methods for storing food that is effective, though they won’t last as long as freeze-dried foods will.
Air drying (dehydration) is another effective way of preserving food. This is done with hot air and evaporation methods. This article explains more about it: Freeze Dry VS Air Dry: 8 Differences that Matter.
Additionally, this is another good article that explains how to preserve food with the dehydration method: Freeze Dryer Vs. Dehydrator: What’s the Difference?
Here are several food preservation methods and their distinctive features:
|Effort required||Low effort||Medium to High effort||Low effort||Medium effort|
|Nutrients preserved||97% of food nutrients will be preserved||40% of food nutrients will be preserved||A little over 40% of food nutrients will be preserved||50% of food nutrients will be preserved|
|Flavor||Taste is better or flavor doesn’t change||Less flavor due to the cooking process||Flavor changes due to water freezing||Taste and appearance changes|
|Food Preservatives Needed||None||May need pectin, sugar, or another preservative agent||None||Salt, sugar, and other preservatives are needed|
|Food Options||Most foods can be freeze-dried||Many foods can be canned||Almost all foods can be frozen||Almost all foods can be dehydrated|
|Shelf Life||Freeze-dried foods last up to 25 years plus||Canned foods last up to 3 years||Deep frozen foods last 6 to 12 months||Dehydrated food can last 1 to 8 years|
Want to know how I know how much nutrition is there when you freeze-dry foods? I’ve got this article for you to read: Are Freeze-Dried Foods Just as Nutritious? Let’s See!
If one preservation method works better for you than others, then feel free to use that instead. For example, some people prefer the texture and taste of canned green beans to the texture and taste of freeze-dried or frozen green beans. Personally, I like frozen or freeze-dried green beans.
This great article explains the canning process in more detail: Freeze Drying vs Canning: What You Need to Know.
Investing in a freeze-dryer is truly worth all of the benefits provided. The lowest price for this machine costs approximately $2,000, and the largest dryer retails for about $5,000. Sometimes you can score a small freeze-dryer for under $2,000, but with recent inflationary concerns, I wouldn’t count on that anymore.
Inflation hurts. Even so, I calculated How Much It Costs To Run A Freeze Dryer: The Complete Guide.
This site uses paid referral links from carefully selected advertising partners. I only promote products I like, use, and recommend. As an Amazon Associate, I can earn from qualifying purchases. Please refer to my disclaimer in the terms and conditions for additional details.
We use and highly recommend Harvest Right freeze-dryers; they are not only easy to use but come equipped with everything needed to get started.
How Many Years Does Freeze-dried Food Last?
Packets or cans of freeze-dried foods that are sealed or unopened can stay at room temperature for more than 25 years. They have been proven to last even longer when stored in cool, dark environments.
Without refrigeration opened or unsealed freeze-dried foods can last up to 2 to 6 months, while canned freeze-dried foods that have been opened can be consumed for up to 2 weeks before expiration.
Can You Store Freeze-dried Foods in The Freezer?
For long-term storage, it is best to avoid storing freeze-dried foods in the freezer. Oxygen absorbers required to sustain their shelf-life cannot function effectively under freezing conditions. Freezing can also affect condensation, which affects freeze-dried foods.
Here’s everything needed to know about the right storage conditions for your freeze-dried foods:
Ideal Temperature: Freeze-dried foods need temperatures between 32°F and 75°F to last. Room temperature is typically okay to store them, but we recommend you store them in a cool, dark place like a pantry. Excessive heat exposure will lead to the breakdown of proteins and the loss of vitamins.
Ideal Light Conditions: Light exposure can lead to the breakdown of nutrients in freeze-dried foods. To avoid this, store freeze-dried food in a dark area or an opaque container. When freeze-dried food has been affected by light, it becomes discolored and tastes funny.
Moisture: Avoid storing freeze-dried foods in a humid area. It’s easy for them to absorb moisture, so make sure to seal them properly when packaging. Always remember to reseal immediately after use.
Insects and rodents can chew through some kinds of packaging like mylar bags, cardboard, and plastic containers (rodents). After packaging freeze-dried foods, storing them in rodent-proof bins will keep such incidences from occurring.
Want to know if you can keep your Mylar bags in a Home Depot orange bucket? You can if you use a liner in it! Read why in my article here: Can You Store Food in Home Depot Buckets?
Oxygen: exposure to oxygen can shorten your freeze-dried food shelf-life considerably and result in the damage of nutrients and change in the appearance of food. So, to ensure that your storage packages are sealed tight, you can use a food vacuum sealer to seal each package.
Foods You Can (and Can’t) Freeze-Dry
It’s true that you can freeze-dry almost anything and everything, but it’s important to know those food items with high fat or sugar content can’t be effectively freeze-dried. Here are some examples of foods that can/cannot be freeze-dried.
Foods that can be freeze-dried
- Mandarin oranges
- Sweet potatoes
- Leafy greens
- Deli meat
- Ground meat
- Game meat
- Cream cheese
- Heavy cream
- Buah Merah
- Hamburger patties
- Mac and cheese
- Keto meals
- Tuna or chicken salad
Candy and Treats:
- Ice cream sandwiches
- Ice Cream
Other food items like coffee, sourdough starters, dog food, spices, herbs, and other kitchen condiments can also be freeze-dried.
If you’re wondering if you Should You Freeze Dry Dog Food? Pros, Cons, and Tips then this is the article for you.
It’s worth mentioning that some freeze-dried food items are hard to reconstitute. These food items include bread, rice, green beans, celery, broccoli, and pasta.
Foods that Cannot Be Freeze-Dried
Foods that are high in fat or sugar are difficult to freeze-dry. There are a few other food items that won’t do well during freeze-drying. Here’s a list of foods that cannot be freeze-dried:
These foods don’t freeze-dry
- Oily and fatty foods
- Sugary foods
- Chai tea
- Heavy cream
- Jellies, jams, and preserves
- Peanut butter
Key Takeaways and Next Steps
Freeze-drying is undeniably the best food preservation method there is. It does take some time to preserve with this method and needs to be reconstituted part of the time. However, it’s an effective way to preserve food for long-term storage.
Ready to take your food storage to the next level? Read this fantastic article about a frequently asked way to store food in your freezer long-term: Can You Freeze Food in Mylar Bags?