I doubt even newbie preppers fail to grasp the difference between canning, smoking, and dehydration methods of food preservation, but many are still a little foggy about the difference between freeze dried and dehydrating crops and meat.
What Is Freeze Dried food?
Freeze dried food is preserved through a flash frozen process. The food is then stored inside of either an airtight container or a vacuum pouch. The moisture in freeze dried food dissipates far more rapidly during the preservation process than it does when being dehydrated.
It is because of the rapid water removal that freeze dried food does not wind up with a sort of deforted shriveled look. Generally, freeze dried food will rehydrate far quicker than dehydrated food.
Freeze drying food is still in its infancy, when compared to dehydrating, smoking, and even canning. This food preservation method is believed to have first been used on a basic level, during the times of the Inca empire.
It was not until the World War II when the United States Military learned how to use freeze drying to preserve medicine, plasma, and ultimately food, for the troops. That’s when it became a more commonplace method of food preservation.
Even though a machine is generally required to freeze dry food, the process is no more complicated than dehydration. The food being preserved is put on racks inside of the machine’s vacuum chamber, then the temperature is quickly lowered to below 32 degrees, and then slowly raised back up above freezing.
Home freeze drying ovens hit the marketplace several years ago, and have come down in cost a little bit since then – but not much. Purchasing such a machine will still run you around $2,000 to $4,500, depending on capacity.
Although there is a high upfront cost associated with this method, in the long run it is typically far more economical an option than purchasing long-term food storage buckets…at least if you grow and raise a significant part of your own groceries.
You can also freeze dry food using a DIY oven, and perhaps even successfully (some claim) without a machine.
What Is Dehydrated Food?
Dehydration is the second method I want to discuss today, and it’s different and cheaper than the freeze drying we just talked about.
Dehydration has been a popular and sound method of food preservation for centuries. The dehydration of fruits and vegetables dates back to 12,000 BC when the Romans and people in the Middle East would use what were commonly referred to as “still houses” to slowly smoke food to remove the moisture from them, in a fashion that was similar but slightly different than the smoking methods used to preserve meat and fish.
photo above: a food dehydrator
Modern electric dehydrators still function using the same premise. When the food is placed inside, and the machine is turned on, hot and dry air is circulated around, over, and beneath the food on its racks. The temperature settings on the machine go high enough to remove all of the moisture from the food, but not so high as to actually cook it.
Moisture is removed from food slowly when using an electric dehydrator, and at an even more sloth-like pace when using a solar dehydrator. The patience required to dehydrate food aside, it is an economical and simple food preservation method.
The dehydration method allows you to preserve foods that can be highly difficult or time-consuming to save otherwise. You cannot water bath or pressure can lettuce, but you can dehydrate it, for example.
Eggs, milk, and other dairy products, including cheese, can all be successfully dehydrated in a standard residential machine that usually costs less than $100.
7 Differences Between Dehydrated and Freeze Dried Food
1. Composition – Freeze dried food will weigh a lot less than dehydrated food. If you tossed some freeze dried fruit into your mouth it would almost immediately become soft. Dehydrated fruit, like banana chips, will maintain their hard texture and weight until they become re-hydrated – or reconstituted.
Because freeze dried food is much lighter weight than dehydrated food, it’s easier to pack when stored in the same type of container (though both are good food choices for your bug out bag).
2. Appearance – This may be the most obvious difference between the two types of preserved long-term storage food. Dehydrated food will always have a squished appearance but freeze dried food will remain looking basically like a smaller version of its original self.
The look of the food likely does not matter to the prepper who merely wants to stockpile as much easily portable food as quickly as and cheaply as possible.
Many if not most preppers who dehydrate food also powder much of it – again changing the appearance of the food. Powdered eggs, cheese, milk, and butter conserve both storage and packing space.
3. Moisture – The primary purpose of both methods is to remove as much water from the food as possible, to prevent the growth of mold and decay which make the food unsafe to eat.
Dehydrating food eliminates approximately 95% of its moisture content, when preserved professionally or with top notch equipment at home.
Depending on the quality of the home dehydrator, the food being preserved could have up to 10% moisture content remaining compared to professionally dehydrated food. Foods that have been freeze-dried have had up to 99% of their moisture content removed. The lower the moisture content the longer it’s shelf life.
4. Nutrition – It is the generally accepted belief that freeze dried foods still possess the vast majority of the nutritional minerals and vitamins they had when fresh – with the possible exception of vitamin C that evaporates rather rapidly during the preservation process.
The dehydration process is not known to alter either the iron or fiber content of the food being preserved, but can cause a decrease in its minerals and vitamins. Typically, a food’s niacin, thiamine, riboflavin, and vitamins A and C are most negatively affected by dehydrating.
5. Cooking – Freeze-dried typically only needs to be soaked in cold water to make it ready to eat in under 5 minutes. Professionally dehydrated food is often recommended to soak in hot water for a minimum of 15 minutes.
Home dehydrated food, in my personal experience, can be re-hydrated in lukewarm or even cold water in five minutes – with the exception of meat which takes longer.
6. Expense – The overall cost difference between freeze dried and dehydrated food has too many variables to calculate. First it depends on type, then amount, energy costs to run a machine, and whether or not the food is being preserved professionally or at home. When purchasing commercially preserved dehydrated or freeze dried food, the dehydrated version is almost always cheaper.
7. Shelf Life – The type of food being preserved and the chosen method both have an impact on shelf life. You can reasonably expect dehydrated powders, fruits, and vegetables to remain safe to eat for around 15 to 20 years if they were both preserved properly by professionals using a quality machine and stored recommended, according to the packaging on many varieties of dehydrated long-term storage food pouches.
Some types of dehydrated food like oats, sugar, hard wheat, salt, honey, and sugar, are advertised to last up to three decades under the same set of circumstances. Professionally freeze dried food is typically advertised to have a 25 to 30 year overall shelf life when stored at between 33 F (0C) and 60F (15C).
photo above: another food dehydrator
Home Freeze Dried vs Dehydrated Food Shelf Life Comparison
Each method of home food preservation results in an extensively long shelf life for the stockpiled food, providing the it’s both preserved and stored properly. Generally, both freeze dried food and dehydrated food will keep as long as water bathed, pressure canned, and smoked food – likely longer.
Freeze dried food that has been stored in a Mylar pouch has been know to remain safely edible for at least 10 years when processed by a residential machine.
Dehydrated food that has been stored in an airtight container, and preferably in a vacuum sealed Mason jar or vacuum sealed bag, has been estimated to remain safely edible for about the same amount of time, but likely a little longer, when processed in a typical home use grade machine.
Once a pouch, bag, or jar of food using either preservation method has been opened, the contents inside will begin to lose its longevity. There is much debate about how long the food can keep once it has again been exposed to air and the moisture in it.
Many folks believe, either based on science or their personal experience, that freeze dried foods must be used within only a few days after being opened. Dehydrated food is believed to be able to be opened, a few scoops taken out, and then resealed again and retain at least a decent portion of its longevity, as long as the remaining food has not gotten wet.
Basically, the results may vary when it comes to the shelf life of opened food; this is why it’s always good to store in small portions just to be on the safe side.
Now, in my personal experience, I have opened and scooped a few tablespoons or so of powdered eggs for camping breakfast cooking, put the Mason jar lid back on the jar (that is no longer vacuum sealed because we primitive camp) and then safely used the remaining contents over the course of a year.
I am not a food safety professional or making any formal recommendation or claim as to the edible nature of opened dehydrated food, I am merely sharing a personal experience that did not cause any side effects.
Which Tastes Better?
Flavor will be way down on your priority list when you have to break into your long-term survival food stockpile. Yet, the taste difference between freeze dried and dehydrated food is still worth considering when engaging in an overall pros an cons list between the two preservation methods.
The answer? It depends.
Personal preference and the overall finicky nature of the individual munching down on the long-term storage food will be the deciding factor of any taste test.
In general, the original taste of the food is often considered to still be held inside. This likely occurs because it was only exposed to a fraction of the heat that its dehydrated counterpart was, and this maintains the bulk of its typical texture.
We both dehydrate and freeze dry the groceries we grow, raise, and occasionally purchase on sale. In my opinion, I cannot taste any real difference when the food being consumed using either method is a fruit or a vegetable after preservation.
When preserving meat, fish, or a whole meal, I would have to say I prefer the taste and longevity of both freeze drying and smoking to dehydrating. That being said, my dehydrating beef jerky recipe rocks!
I have also found that I prefer dehydrated dairy over freeze dried. But really, you just can’t beat the freeze dried ice cream bits – what a fabulous morale booster they will be during a long-term SHTF event.
Ice cream is the only dairy product that I have not been able to dehydrate. Even my finicky daughter cannot tell the difference between “fresh” sour cream and cottage cheese and the reconstituted versions from my home dehydrator.
Food Preservation Machine Pros And Cons
We now have two dehydrating machines, a middle of the road one I bought to see if I like preserving food by that method and to determine how well it worked. Once I nearly wore it out from happy use, we bought a $110 model on sale for $69 in the middle of the winter when no one was thinking about putting up their garden.
During the summer and early fall I now keep both humming on my kitchen counter to preserve food as quickly as possible once it has been picked.
The only downside to using the lower end machine is its noisy fan. It dries food as quickly and thoroughly as the more expensive, but nearly silent model. Both are Nesco brand, I borrowed a friend’s Excalibur machine before upgrading from our first machine and found no quality difference between either machine, just a shape and price difference.
Dehydrators come in both round and square versions, with a square one being more handy for meat, in my opinion. Buying tray liners and screen accessories, even if your chosen machine comes with a few, will come in a lot more handy then you might think when preserving your heirloom seeds from one season to the next.
Even if the machine comes with a ton of trays or the box states you can add a ton of trays, I have found using more than four or five, depending upon the machine, only serves to increase drying time and uses more electricity.
A freeze drying machine is a big expense for most of us middle class preppers, but it is definitely one worth saving up for if you are going to include freeze dried food in your preps.
When you compare the cost of a small machine with how much money it would take to buy commercial freeze dried food, it’s a no brainer for anyone who is growing or raising food already.
A small 16 and a half inch by 25 inch Harvest Right freeze dryer costs just under $2,000. According to the manufacturer, the food preserved in the machine will last for 25 years. The Freeze dryer is capable of preserving 4 to 7 pounds per batch. It runs on a standard 110-volt outlet and should work function well on generator power as well, depending upon capacity.
I see no reason to limit yourself to only one type of food preservation. Hedge your bets. You don’t stockpile only one type of weapon, right?
I will never stop water bath and pressure canning some of our harvest, but now that I am preserving a significant portion of our bounty using this machine, there sure is a lot less work to do each September.