Having the ability to freeze dry your own food will save money and ensure you always have a supply of food for emergencies. If you live in remote places like Alaska, knowing how to freeze dry food for long term storage can be the difference between life and death in those long harsh winters. Most bush Alaskan’s spend the majority of the summer (which in some places is only 2-4 months) preparing for the winter. Knowing how to preserve food for long term storage is a way of life.
Even if you do not live in remote places like Alaska, knowing how to freeze dry food is a great skill to have. Freeze dried foods are excellent for camping trips or to have around for emergencies.
What is Freeze Drying?
Like standard food drying, freeze drying’s goal is to also completely dry the food. The difference is in the method. The standard drying of food involves laying the food in the sun, in which natural evaporation will cause the water to evaporate.
Freeze drying your food on the other hand drastically speeds up the natural drying process. In essence, moister is remove from food by sublimation. In order to do this, a vacuum (or drastically reducing the pressure) is applied to the food. This causes the moister to freeze and then turns into a gas. This leaves the food dry. This is the best overall method for freeze drying. Other additional methods include using a freezer or some dry ice (see below).
When ready to consume, freeze dried food can be re-hydrated quite easily, since the process leaves microscopic pores in the food which allows reconstitution to occur much quicker.
Benefits of Freeze Drying Food
- Leaves food with same nutritional value
- Leaves food flavor and taste intact
- Easier to transport (very light)
- Easier to store
- Long term storage
- Food texture changes
- Process is not as simple as standard drying of food. Additional care is needed to ensure food is properly freeze dried.
Top 3 Methods on How to Freeze Dry Food for Long Term Storage
First, Prepare Your Foods
No matter what method you use for the actual freeze drying, the first step involves food preparation.
First you will want to select foods that have lots of water in them. These tend to work best for preservation through freeze drying. Some good examples of foods that have lots of moister include
- Full Meals!
Once you have selected your food, ensure that it is currently fresh and not rotting. For fruits and veggies it is best to freeze dry them when ripe and in season.
If you are freeze drying a meal, wait until it is cooled down. Do not freeze dry a meal that has already been refrigerated.
The idea is to freeze dry foods/meals at their most optimal fresh and ripeness.
Once your food has been selected, wash and then dry the food the best you can. If possible start cutting the food into smaller pieces to help the freeze drying process. Things like apples, bananas and potatoes are good examples.
At this point depending on your budget or tools on hand, there are several different ways to freeze dry food for long term storage.
Method 1. Freeze Drying with Dry Ice
- The first step is to put your food into a freezer safe bag. Try to remove as much air as possible while keeping the bag flat. Keep the food evenly distributed.
- The Fun Part. Put your bag into a cooler (tail gate type of cooler is fine). Then carefully cover the bag with dry ice. It is OK to layer bags and dry ice if you have more than one bag of food to freeze dry.
- Freeze It. You will need a freezer with enough room for your cooler. Place your cooler in your freezer and leave it there for about six hours (with the lid on). Check back after about a day. If the dry ice is gone, your food should be freeze dried!
- Storage. Remove the bags and store them in a safe place. You could put them back in the freezer or in your kitchen pantry.
Method 2. Buy A Freeze Dryer!
If you want the simplest no brain method for freeze drying your food, then go with the professional option. This includes buying a freeze drying appliance that will ensure your food is properly freeze dried.
Below we list the best-selling freeze driers and tools that can be found on Amazon. Yes, these are expensive but worth it in the long haul. Also keep in mind it’s only been in the last couple years that more commercially viable freeze driers are becoming available to the general public. Historically freeze driers are used by big companies and can cost up to $30k.
Freeze Driers & Tools
- VacMaster VP210 Chamber Vacuum Sealer
- VacMaster Vacuum Chamber Pouches
- Vacuum Sealer for Food Preservation
- Labconco FreeZone 4.5 Liter Console Freeze Dry System (most expensive, but gives you an idea of what the commercial giants look like)
Most food freeze driers work off of the same principle. Follow the manual that came with the machine. This will involve placing the food on trays (not clumped up), then turning on the machine for a specified time. Once finished you will place the food in air tight containers for long term storage.
Method 3. Freeze Drying with Your Freezer
- Place your food chunks, slices onto a tray. Make sure they are all separate and not touching each other. This method works best with an empty freezer.
- Choose a freezer. You will need the coldest freezer you can find. It also works best when nothing else is in the freezer. If you do not have a deep freezer you could try using a standard freezer and set it to the coldest setting.
- Put food in the freezer. Place the food tray into the freezer and leave it alone for about a week. It is VERY important that you do not open up the freezer anytime during the sublimation process. Not only can this retard the freezing process but it will also cause ice crystals to form on the food.
- Test. After a week, take a piece out of the freezer and let it thaw. If the piece of food turns black, then it’s not done yet.
- Storing. Once the food has been freeze dried (all moister has been removed) store it appropriately in a vacuum sealed bag.
One of the best examples of a freeze dried food is Astronaut ice-cream. I remember going to the science museum on my school field trips as a child always looking forward to this freeze dried ice cream. I wondered how they did it, how could you dry out something that was so wet naturally? It was not until I was older that I learned how to freeze dry food for long term storage and started doing it myself. It is a great technique to master (which is even easier with today’s devices) and can help save your life in an emergency.