Freeze-drying is a food preservation process where food is quickly frozen, and then the ice is turned into water vapour. It is then removed by placing the frozen food in a vacuum, resulting in it being dehydrated.

Normally freeze drying is done by professional companies with specialist equipment. But, it can be done at home.

What is the point of freeze drying food?

Freeze-dried foods are used by astronauts, campers, backpackers, food manufacturers, doomsday preppers and the military. You can buy freeze-dried foods for home use. For example, fruit pieces that you might find in some cereals and space ice cream. You can get entire freeze dried meals, as almost all foods can be freeze-dried.

Advantages and Disadvantages of Freeze Drying Food

Advantages

As the water is completely removed from the food, it is very light. This is why it is used by astronauts, campers and the military, as it is easier and cheaper to move around.
Freeze-dried foods tend to retain most, if not all of their nutrients, taste, shape and size.
You don’t need to refrigerate freeze dried food, and it can last for months or years.
Freeze-dried foods can be rehydrated very quickly, unlike dehydrated foods.

Disadvantages

Freeze drying food is can be quite expensive due to the specialised equipment.
Freeze dried food takes up almost as much space as fresh foods, while dehydrated foods take up less space.

Even though freeze dried foods can be expensive, they can come in very useful. You just simply rehydrate them with cold or hot water. Therefore, you can carry the food you need without worrying about having to keep it hot or cold. Their long shelf life also makes freeze-dried foods a viable option for emergency food stores.

How to Freeze Dry Food

Before we get in to how to freeze dry food, there is a little bit of preparation to do.

1. Choosing the types of food for Freeze Drying

As we said before, fruit and veg with high water content are the best ones to freeze dry, as are certain meats and fish. It is best to Freeze dry food at the peak of its ripeness or freshness. This is because it will taste as good as it possibly can when it’s rehydrated.

Fruits and vegetables should be freeze dried when they are in season and fully ripe.
Meat should be freeze dried after it has been cooked and cooled, as should full meals. Make sure you don’t freeze dry them after they have been in the fridge for a few days, or they’ll taste like leftovers when you bring them back to life.

You really don’t want to freeze dry foods that won’t taste good when they are reconstituted. Some foods, such as berries and apples don’t need to be reconstituted and taste nice as they are. However, meat or spaghetti, will need to be reconstituted with moisture in order to be edible. Examples of foods that cannot be reconstituted are bread, cake or anything yeast based. This is because their texture is altered by its freshness.

2. Get your food ready for Freeze Drying

Wash and dry the food thoroughly if it needs to be
Slice the food into small pieces. Cut apples, peppers, potatoes and other fruit and vegetables into small chunks, so that the moisture is easily removed.

How to Freeze Dry Food Using Different Methods

1. Freeze Drying Machine

The easiest way to freeze dry food is to use a freeze drying machine. These are a little bit bigger than a microwave and do all the hard work for you. Simply slice the food up and lay it on the trays, switch the machine on and let it do its thing. 24 hours later your food is perfectly freeze dried without any intervention from you.

Have a look at the video below to see how the Harvest Right Home Freeze Dryer works.

The Best Freeze Drying Machines in November 2023

1

Rating is 5 out of 5

Food Dehydrator, 10 Stainless Steel Trays Food Dryer Machine for Candy, Food and Jerky, Herbs, Veggies, Fruits, 800W Electric Dryer Machine for Candy, Digital Temperature and Timer

Make Low-calorie Healthy Snacks: Using this food dryer machine, you can dry a variety of vegetables, fruits, meats, flowers and other foods, easily locking the minerals and vitamins in the food. It retains the nutrition of the food itself without adding various food additives, so it is healthier compared to snacks in the store.
Higher Efficiency & Shorter Drying Time: The 800w power can achieve the drying effect you want in a shorter time, so it is both efficient and energy-saving.
360° Airflow Circulation Technology : The dryer machine adopts a double-layer stainless steel structure that can better insulate the outside to prevent heat loss. The built-in 2 large fans use 360° airflow circulation technology to ensure more even heat distribution, so that food is dried more evenly and quickly.
Food-grade Materials: The tray is made of food-grade 304 stainless steel without BPA, so you don't have to worry about food hygiene. It also has an automatic shut-off function and overheating protection, so you can use it with confidence.
Temperature and Time Adjustable: The drying temperature can be adjusted between 30-90 ℃. The timer can be set between 0.5-24h. Therefore, this food dehydrator can encompass multiple kinds of food drying work.
10 Trays Capacity: It has 10 trays, each with a size of 11.81*11.02inch, so the food dryer machine has excellent expansion space allowing you to dry multiple foods at once.
Process Visibility: It uses a glass front door and a built-in LED light, which allow you to keep track of the drying situation and discover subtle changes in the food drying process.
Easy to Operate: There is a clear LED operation panel on the front of the machine. You just need to plug in the power, press the switch button and then set the time and temperature to start drying!
Great Durability: It is made of double-layer stainless steel construction, so it is very sturdy. The tray also does not rust easily, so it can be used for a long time.

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2

Rating is 4.9 out of 5

ChefWave Commercial Countertop Electric Food Dehydrator Dryer Machine - Digital Temperature Control & Timer, 10 Stainless Steel Trays - for Dried Fruit/Veggie, Meat Beef Jerky, Herbs Dehydrator

Healthy and Nutritious: The ChefWave electric professional food dehydrator freeze dryer can make the most beneficial and tastiest dried snacks like fruit leather, vegetable, herbs, pet food, or meat jerky and hold all of their nutritional value and flavor!
10 Removable Trays--Sleek Design: This large, stainless steel countertop kitchen appliance features six drying racks for uniform drying. It flaunts a modern design with a transparent door, making it easy to monitor. Also includes a recipe book.
LED Digital Control Panel: Easily control this freeze dryer machine with the digital screen. Set the temperature and time and adjust as needed. It features temperature controls between 95 F and 167 F. Timer can be set between 30 minutes and 24 hours.
Packed with Tools and Accessories: Includes everything you need! 10 large 13” x 12” stainless steel drying racks, drip tray, 2 mesh sheets, and 3 Teflon sheets for fruit leathers, banana chips, beef jerky, trail mix, and pet snacks!
1 Year Warranty: We want to ensure that you’re delighted with our products. We guarantee that it will work exactly as it should. This warranty covers parts and labor to enjoy using it worry-free! ETL certified.

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3

Rating is 4.8 out of 5

Ivation 9 Tray Countertop Digital Food Dehydrator Drying Machine 600w with Preset Temperature Settings, Auto Shutoff Timer and Even Heat Circulation for Beef Jerky, Fruits, Vegetables & Nuts

Enjoy Homemade Easy Healthy Snacks,Without Additives or Preservatives, at a Fraction of the Cost of Commercially Dehydrated Foods
Perfect For Drying Fruit Slices, Long-Lasting Dried Herbs, Delicious Beef Jerky & More, Also an Economical Way to Preserve Foods
Rear-Mounted Fan Is Designed To Promote Even Drying with Optimal Airflow Without Overheating, and a Adjustable Thermostat with Automatic Shutoff Timer Ensures That Foods Are Dehydrated At Their Optimal Temperature and Crispiness
9 Spacious, (13” X 12”) Adjustable Drying Racks Accommodate A Wide Variety Of Fruits, Herbs, Vegetables, And Meats, Great For Large Families, Gardeners, Sportsmen, Outdoor Hobbyists, Health-Conscious Enthusiast
Digital Thermostat has Eight Temperature Levels From 95º F To 158º F, Includes 1 Nonstick Fine-Mesh Sheet For Drying Small Food Like Herbs, 1 Solid Sheet For Making Fruit Roll-Ups, Overheating Safety Protection, Complies With US Electrical Safety Regulations ETL, Product Dimensions: 17.71 x 13.5 x 16.3 inch

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2. How to Freeze Dry Food with your Freezer

Place the prepared food on a plate or tray making sure the pieces of food are not too close together or touching.
Put the tray of food in the freezer. Ideally, the freezer should be empty of other items.

If you choose this method, do not open the freezer while the food is freezing. This is because it will slow the freezing process, and cause ice crystals to develop on the food.

A deep freezer, is best and the food should be frozen at the lowest temperature possible.

3. Keep the food in the freezer until it has freeze dried. It will take about a week for all of the moisture to be removed from the food.

To make sure the food is completely freeze dried. Remove a piece of it and allow it to thaw. If it turns black, the food is not freeze dried yet.

Once you are sure the food is completely freeze dried, put it in freezer bags. Make sure you push the air out before you seal the bags. You can now store them in your freezer, a cool dry cupboard or in your emergency preparedness kit.

The Best Chest Freezers in November 2023

1

Northair Chest Freezer - 7 Cu Ft with 4 Removable Baskets - Reach In Freezer Chest - Quiet Compact Freezer - 7 Temperature Settings - White

Rating is 5 out of 5

Northair Chest Freezer - 7 Cu Ft with 4 Removable Baskets - Reach In Freezer Chest - Quiet Compact Freezer - 7 Temperature Settings - White

PERFECTLY QUIET - Unlike other chest freezers, the Northair Chest Freezer combines a modern design with a whisper quiet compressor which means you can say goodbye to low level hums and enjoy the sound of silence. Feel more relaxed in your own home with reduced noise distractions.
OPTIMAL STORAGE - At 7 Cubic Feet, the Northair Chest Freezer is compact enough for the modern home however spacious enough to store a sizeable amount of food. Each freezer measures 35.4"(L) x 21.8"(W) x 32.9"(H) and is light and easy to move. Four baskets are also included as a bonus.
EASY TEMPERATURE ADJUSTMENT - Easily change the temperature by using the adjustable thermostat located on the exterior. Choose a number between 1 (Off) to 7 (Coldest). Temperatures range from -4°F and 6.8°F which allows you to customize freezing for your favorite foods.
ENERGY SAVING - Unlike many other models on the market, the Northair 7 cubic feet small chest freezer has a modest energy consumption of 0.68 kWh/24h. This not only means Northair deep freezers are more environmentally friendly but they also allow you to save on your next energy bill.
PREMIUM USER EXPERIENCE - The steady lid allows you to effortlessly access the chest freezer hands-free; holding itself open between 45° and 90° angles. Just like with our whisper quiet compressor, we have engineered the door mechanism to be very quiet when opening and closing the door.

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2

Koolatron Large Chest Freezer, 7.0 cu ft (195L), White, Manual Defrost Deep Freeze, Storage Basket, Space-Saving Flat Back, Stay-Open Lid, Front-Access Drain, for Basement, Laundry Room, Cottage

Rating is 4.9 out of 5

Koolatron Large Chest Freezer, 7.0 cu ft (195L), White, Manual Defrost Deep Freeze, Storage Basket, Space-Saving Flat Back, Stay-Open Lid, Front-Access Drain, for Basement, Laundry Room, Cottage

7.0 cu ft (195 L) Capacity: Spacious 7.0 cubic foot (195 liter) flat-back deep freeze offers plenty of storage for your frozen goods so you can buy in bulk, reduce food waste and save money
Manual Defrost with Easy-Access Drain: Front-mounted drain allows easy access for hassle-free draining when defrosting or cleaning your freezer
Removable Storage Basket: Organize your contents and keep small and commonly used items easily accessible with a hanging wire basket made of corrosion-resistant vinyl-coated wire
Convenient Stay-Open Lid: Freezer lid opens easily with one hand and stays open for as long as you need; rear-mounted hinges prevent the lid from hitting the wall and ensure a tight seal when closed
Reliable Compressor Cooling: Quiet, dependable compressor technology, external temperature control dial, and strong magnetic lid seal maintain your freezer's temperature between 0 and -24C (32 and -11.2F)

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3

Midea MRC04M3AWW, White 3.5 cu. ft. Mini Freezer, Cubic Feet

Rating is 4.8 out of 5

Midea MRC04M3AWW, White 3.5 cu. ft. Mini Freezer, Cubic Feet

Mechanical Control with Adjustable Thermostat from -12 to -28 Degrees (Great for Storing Frozen Food, Ice Cream, Ice, etc)
Contains 1 Hanging Wire Storage Basket
Hinge-Style Door Remains Open from 45 to 75 Degree Angles
Full 1-Year / Compressor 2-Year Warranty

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3. How to Freeze Dry Food with Dry Ice

Place your food in freezer bags and lay them out flat.
Push all the air out of the bags before sealing them up.
Make sure you seal the bag up airtight.
Place the freezer bags in a large cool box and cover the food with dry ice.
Put the cool box in the freezer.
After 6 hours, put the lid on to the cool box.
After 24 hours, check to see if you still have dry ice. If it has gone, the food is ready.

Remember to always wear gloves and long sleeves while handling dry ice.

4. How to Freeze Dry Food with a Vacuum Chamber

Place your food on a plate or tray. Make sure you spread it out so that the pieces of food are not too close or touching.
Place the tray of food in the freezer and freeze until solid.
Place the frozen food in the vacuum chamber set to about 120 m Torr. Set the temperature to 10 °C (50 °F).

This process should take about a week depending on the set parameters. Check a piece of food after waiting the proper time to make sure it is properly freeze dried.

The Best Vacuum Chambers in November 2023

1

VEVOR 3 Gallon Vacuum Chamber and 3.5 CFM Pump Kit, Tempered Glass Lid Vacuum Degassing Chamber Kit, Single Stage Vacuum Pump with 250 ml Oil Bottle, for Stabilizing Wood, Degassing Silicones, Epoxies

Rating is 5 out of 5

VEVOR 3 Gallon Vacuum Chamber and 3.5 CFM Pump Kit, Tempered Glass Lid Vacuum Degassing Chamber Kit, Single Stage Vacuum Pump with 250 ml Oil Bottle, for Stabilizing Wood, Degassing Silicones, Epoxies

Heavy Duty Vacuum Pump: Single-stage pump design for the higher and more stable ultimate vacuum! Free Air Displacement: 3.5 CFM, Vacuum Level: 40 microns, Intake Fitting: 1/4"SAE Male, Voltage: AC120V/60 Hz, Oil Capacity: 250ML. Pump oil type: vg100 (kinematic viscosity 46 mm2/s, viscosity 100mm2/s). Ideal for wood stabilization and resin degassing (i.e. cactus juice, crocodile venom, Minwax, etc.)
4-Pole Pure Copper Motor: The motor has high torque for more efficient operation. The T-shaped heat sink and cooling fan help the pure copper motor to effectively dissipate heat, allowing it to work continuously for over 2 hours. And with added overheat protection, you can enjoy the stabilized performance and longer service life for your motor.
User-Friendly Design: Get ready to experience complete comfort! Designed with comfort in mind, the ergonomic handle is shaped to fit your hand and features a rubber-clad iron handle structure for easy lifting and holding. With the bonus of a sight glass and oil level scale, you can easily monitor the status of your oil level and lubricating oil, ensuring timely maintenance.
High-Quality Vacuum Chamber: The 3-gallon vacuum chamber is equipped with a tempered glass top and rubber seal to avoid organic discoloration and damage and ensure the airtightness of the entire vacuum system. The one-piece stainless steel body with a handle is durable and easy to carry. Extra two silencers reduce noise and make the pump run more quietly.
Everything You Need: We provide a Vacuum Chamber, Toughened Glass Bucket Lid, Vacuum Gauge, Red & Blue Manual Shut-off Valve, Sealed Intake Fitting, Open Hole Pre-filled Barrel Lid, Vacuum Gauge Ball Valve, Vacuum Gauge Air Intake Filter, Connection Hose(1.5 m rubber hose, 1/4 inch SAE female at both ends), Silicone Pad(20 x 20 cm), 250ml Bottle of Vacuum Pump Oil.
Quality control: The vacuum pump has undergone 100% quality testing before leaving the factory to ensure the complete performance of each product. Friendly Note: A small amount of oil which is injected in the machine during the factory quality test may leak out in transit, which do not affect usage effect.
Method for checking the leakage of the vacuum pump: Method 1: Connect the vacuum pump inlet port with a vacuum gauge. Method 2: Tighten all three air intakes, turn on the machine, and after a few minutes, check for oil mist. If there is no oil mist, it indicates that the vacuum pump is in good condition. If there is continuous smoke, it indicates that the vacuum pump is leaking. P. S. The refrigerant meter cannot detect vacuum. Please repeatedly check whether the external interface is tightened.

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2

BACOENG 5 Gallon Vacuum Chamber Kit with 4.5 CFM 1 Stage Vacuum Pump HVAC

Rating is 4.9 out of 5

BACOENG 5 Gallon Vacuum Chamber Kit with 4.5 CFM 1 Stage Vacuum Pump HVAC

★ TEMPERED GLASS LID - Not only high-strength, impact resistant but also gives a better overview of the work. Specially designed for stabilizing wood and other experiments with volatile compounds. Ultra-sealed design to maintain high vacuum OVER 24h. WON'T CRACK!
★ HEAVY DUTY VACUUM PUMP - An integrated tank and all copper motor maximize the vacuum's power. It delivers 4.5 CFM flow rate and -29.92inHg vacuum with relatively low noise.
★ SS304 CONTAINER - Strong and durable stainless steel container with chemical-resistant silicone gasket. Silicone gasket to be used over 10,000 times without deterioration.
★ LIQUID FILLED GAUGE - Resists vibrations and keeps the gauge accurate. Measuring range of vacuum gauge：0-30inHg, 5 Feet Reinforced Vacuum Hose Connect Directly To Vacuum Pump 1/4" SAE.
★ APPLICATIONS - Stabilizing wood, degassing urethane, silicones, epoxies, stabilize, extracting essential oils from organic materials, etc

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3

Bestauto Vacuum Pump 2 Gallon Vacuum Chamber Silicone Expoxy Degassing with 4CFM 1/3HP Single Stage Vacuum Pump

Rating is 4.8 out of 5

Bestauto Vacuum Pump 2 Gallon Vacuum Chamber Silicone Expoxy Degassing with 4CFM 1/3HP Single Stage Vacuum Pump

Heavy Duty Vacuum Pump: FAD: 4 CFM, Single Stage; Power: 1/3 HP; Ultimate Vacuum: 5PA. Our HVAC vacuum pump is made of heavy-duty aluminum alloy with good heat dissipation abilities, durable and sturdy. A strong copper motor is adopted for stable operation. Besides, it features a non-oil flow back design to avoid chamber contamination.
Premium Vacuum Chamber: Capacity: Capacity: 2 Gallon. The stainless steel vacuum chamber is of high strength, can withstand up to 160 ºF. It is equipped with two silencers to reduce the noise and make the pump run quieter. 50-micron air filter reduces airflow back into the chamber for purging and avoids debris from entering the chamber.
Easy Monitoring & Cooling: This AC vacuum pump comes equipped with an oil viewing window to monitor oil levels easily and avoid oil deficiency. Intelligent radiators can cool themselves and avoid stuck things from burning out. The built-in thermal protection function can avoid the machine from burning.
Practical Accessories: The vacuum chamber has a 3/5" acrylic crystal lid, convenient for you to observe the internal state, and is bulletproof. The non-stick silicone gasket allows you to wipe off mixtures easily. The hose is built with steel wire to ensure strength & durability.
Wide Application: The device comes with one 4CFM vacuum pump and one 2 gallon vacuum chamber of superior quality. The pump features an ergonomic handle for superior comfort and portability. The vacuum chamber kit is suitable for household air conditioning, automobile maintenance, vacuum packaging, refrigerator vacuum, Industry, etc. And it also fits for

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4

ABLAZE 5 Gallon Upgraded Tempered Glass Lid Stainless Steel Vacuum Chamber Perfect for Stabilizing Wood, Degassing Silicones, Epoxies (5 Gallon)

Rating is 4.7 out of 5

ABLAZE 5 Gallon Upgraded Tempered Glass Lid Stainless Steel Vacuum Chamber Perfect for Stabilizing Wood, Degassing Silicones, Epoxies (5 Gallon)

★ Tempered Glass Lid - No cracks on the lid again
★ Liquid Filled Stainless Steel Vacuum Gauge-Shock Proof and Durable
★ SS304 CONTAINER - Strong and durable stainless steel container with chemical-resistant silicone gasket.
★ APPLICATIONS - Stabilizing wood, degassing urethane, silicones, epoxies, stabilize, extracting essential oils from organic materials, etc

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How to Reconstitute Freeze Dried Food

Remove the freeze dried food from the freezer bags and put it in a bowl or saucepan.
Boil some water on the stove.
Pour some boiling water over the freeze-dried food. As it absorbs moisture, it will fill out. If it seems to need more water, pour a little more over the food. Repeat until the food is fully reconstituted.