Those who decide to delve into the world of backpacking meals are bound to bump into the issue of dehydrated vs freeze-dried backpacking meals at some point.
A lot of outdoor enthusiasts are confused by the distinction between these two terms. An important thing to mention here is that freeze-drying isn’t completely different from dehydration, but rather a form of it. Therefore, freeze-dried backpacking meals are quite similar to dehydrated backpacking meals.
However, the process of freeze-drying is different from regular dehydration and results in meals that differ in calorie density, nutritional value, convenience, and weight. In this article, we’ll compare these two types of foods from the standpoint of outdoor recreation and weigh their advantages and disadvantages.
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What are Freeze-Drying and Dehydration?
“Freeze-dried” and “dehydrated” both refer to processes of having the water removed from the food. Since yeasts, molds, and bacteria require water to grow and thrive, the process of water removal prevents them from spoiling the food. In other words, the more water is eliminated from a particular meal, the longer it will be preserved.
Although a lot of folks use the terms “freeze-dried” and “dehydrated” interchangeably, there are some significant differences between these two processes – let’s take a closer look:
What is Freeze-Drying?
Unlike that of dehydration, the history of freeze-drying is much shorter. The oldest reports of this process being used by people come from the Andes mountains in the 1200s. It wasn’t popularized all the way until the 20th century, especially during World War II, when it was used to preserve food, medicines, and blood for long-distance transporting.
As its name suggests, this process sees food being first frozen and then placed in a vacuum. There, the temperature is gradually raised in order for the water contents to become ice (i.e. to solidify) and then convert to gas. If this sounds confusing, you’re not alone – a lot of people don’t really understand how water transforms so quickly from a solid to a gas.
This is because most people observe water’s behavior at regular atmospheric pressure. We all know at which temperatures water boils (100ºC) and freezes (0ºC). However, things are quite different at low atmospheric pressures, for example at the top of the world’s highest mountains.
There, water starts to evaporate at temperatures below 100ºC due to lower air pressure. In other words, you’d be able to put your hand into a bowl full of boiling water and not suffer any serious injuries. Pretty weird, wouldn’t you say?
What’s even weirder is that, in these conditions, water sometimes doesn’t even exist. Instead, it transforms directly from vapor to ice and vice-versa. The name of this process is sublimation and that’s precisely how freeze-drying functions.
Since it’s pretty complicated when compared to regular dehydration and involves things like an atmospheric pressure control and freezing temperatures, the process of freeze-drying of foods is something usually carried out only commercially. Home-use freeze dryer units do exist, though, but they’re very noisy and extremely expensive.
Furthermore, due to the fact that the vast majority of them are produced commercially, freeze-dried meals can get quite pricey – they typically retail at around $5-15. Obviously, the price tag goes up for those who are planning to take lots of such meals to their long-distance backpacking adventures.
What is Dehydration?
In this process, low heat (35 to 60ºC / 95 to 140ºF) is used to remove water from the food. The temperature is intended to be low enough to prevent the food from getting cooked, but still high enough to force water to evaporate.
As you probably already know, this process doesn’t really require the use of advanced machines or techniques. One can easily dehydrate food by drying it out in the sun or wind. After all, these simple yet very effective methods were used by people of all civilizations for thousands and thousands of years.
However, an important thing to mention here is that these traditional techniques require appropriate conditions, such as dry air or direct sunlight. If these requirements are not met, the food can easily go bad before the water is removed. And that’s precisely why a vast majority of people use modern appliances called electric food dehydrators.
This appliance consists of simple plastic trays (or racks) with a lid on the top. These racks feature small holes that allow ventilation. A device that resembles a hair dryer blows warm air throughout the appliance and, in that way, dries the food. When compared to sun drying, electric food dehydrators are significantly more efficient and provide users with more accurate control of the temperature.
With this technology being fairly simple, electric food dehydrators are very affordable. Depending on its features, build quality, and size, this type of appliance will typically cost from $30 to $150. It turns food dehydration into a very simple process and allows users to control low temperatures (in order to avoid cooking) and arrange their food of choice in thin layers.
Dehydrated vs Freeze-Dried Backpacking Meals – The Standoff
In this part of the article, we’ll compare dehydrated and freeze-dried food in five different categories: taste, nutrition, preparation, weight, and shelf life. By the time you reach the article’s end, you should be able to figure out which type of food suits your needs the best.
Let’s be honest – it all comes down to taste, and that’s the thing that can make all the difference. No one likes eating backpacking meals that taste like cardboard. Therefore, it is vital for the original flavor to stay untouched.
The good thing is that both of the methods we’re comparing here are more than capable of preserving the food’s original flavor. However, as we’ve explained above, they are still quite different from each other and one of them is better at keeping the flavor at the same level as before.
Freeze-dried backpacking meals are a clear winner in this category due to the fact that they’re prepared with little heat, allowing the food to stay almost the same as it was. Dehydration, on the other hand, removes the water from food by using a lot of heat, which, in turn, affects its smell and taste. The flavor won’t change that much, but you will certainly be able to notice the difference in texture and taste.
The process of freeze-drying leaves most of the nutrients present in food intact. Once rehydrated, a freeze-dried backpacking meal will taste and feel almost like it’s fresh.
In simple terms, you can look at this process as a method of freezing some kind of food and then unfreezing it when you’re hungry and want to eat it. There is little to no change in taste, texture, but also in nutritional value.
On the other hand, dehydrated food goes through the process of evaporation. It is prepared in appliances such as electric food dehydrators or large ovens that make use of low heat to eliminate moisture from food. Unfortunately, this has a negative effect on the meal’s nutritional value – the meal can lose as much as 40% of its original nutrients in the process.
Freeze-dried food loses a lot less original nutrients – only 2-5%. So, in terms of nutritional value, freeze-dried backpacking meals definitely take the cake.
Freeze-dried meals are exceptionally easy to manage when it comes to preparation. Due to the fact that it comes pre-cooked, all that one has to do to enjoy a freeze-dried meal is to add a bit of water and wait for a couple of minutes. You may even notice that the package is more than 20 years old – freeze-dried meals have a very long shelf life (more on that later).
Dehydrated food, on the other hand, is just as easy to prepare. However, the process is a bit different. Since it’s originally made raw, a dehydrated meal needs to be cooked before it can be eaten (if you’re not planning to eat it on the go, of course). To rehydrate it and give it back its original texture, one can also boil dehydrated food.
It takes around 20 minutes to do this, which shouldn’t be an issue for most hikers. However, if you’re one of those trekkers who like to move fast and light and you’re usually in a hurry, keep in mind that the freeze-dried meals take less time to be prepared.
Those planning to store food somewhere in their homes for emergency situations certainly don’t have to worry about its weight. However, those who want to carry the food with themselves on backcountry adventures have to pay special attention to the food’s weight.
When compared to dehydrated food, freeze-dried meals are easier to manage and typically have a lower weight. So, if you’re planning to go on a long-distance outdoor adventure, freeze-dried food is your best bet.
However, there’s a catch. As we already said. making a meal out of such food requires the use of water. This means that you’ll also have to carry some extra water in order to rehydrate your freeze-dried food.
On the other hand, some types of dehydrated food require no additional preparation and can be eaten on the go. Freeze-dried foods such as vegetables and fruits can be consumed without rehydration, so the ultimate decision is really up to you.
The thing that causes food to decompose and deteriorate is moisture – it’s as simple as that. That’s precisely why fresh meat and fruit can’t really last for more than a couple of days before you have to throw them away.
Types of food that contain a lot of water need to be consumed as soon as possible. So, let’s take a closer look at how good the two food preservation methods we’re comparing here are at moisture removal:
Food dehydration is a simple process – the meals are prepared through the elimination of water from the fresh ingredients. To get the best results, one has to use a commercial-grade electric food dehydrator. However, as we’ve mentioned above, one can also use some homemade techniques.
Unfortunately, though, these traditional methods are able to remove only about 70% of the water from any type of food. Professional electric dehydrators, on the other hand, are much more efficient and can remove as much as 98% of the water from a particular piece of food.
Most foods that go through this process will have a shelf life that is no longer than one year. However, using a really expensive high-end dehydrator to remove the water can prolong this period to a whole 15 years. Pretty impressive, wouldn’t you say?
No matter how good this sounds, it still can’t beat freeze-drying when it comes to shelf life – freeze-dried meals can be stored for even longer. As described above, the process is a complicated one – first, the temperature is quickly lowered in order to freeze both the moisture and the food particles. Then, the pressure is lowered too, causing the ice to convert to steam (sublimation) and get expelled from the food.
When it’s executed properly, this complex technique removes around 99% of water, giving freeze-dried meals a shelf life of 25 years. While both food preservation methods we’re comparing here significantly prolong the shelf life of many foods, freeze-drying is a clear winner – freeze-dried meals stay edible two or more times longer than their dehydrated counterparts.
Dehydrated vs Freeze-Dried Backpacking Meals – The Verdict
In summary, freeze-dried backpacking meals beat dehydrated food in most categories. They stay edible for a longer time, they keep 99% of the food’s original nutritional value, and they’re significantly lighter and more practical to use.
However, that doesn’t mean that dehydrated backpacking meals should be discarded altogether. The biggest advantage of opting for dehydrated food for your backcountry trips is the fact that you can make it at home. This will allow you to save some money, pack the correct quantities, decide which ingredients will go into each meal, as well as to dial every recipe to your taste.
Consider the differences we’ve listed above, as well as the advantages and disadvantages of each option, before making the ultimate decision.
I love hiking. From the Camino de Santiago to the West Highland Way in Scotland or simply a great day hike on the weekend. Hiking refreshes me, my mind, and keeps my body reasonably fit. So far I have walked three Camino routes and many other long distance hikes in the UK, Canada, and around the rest of Europe. One of the best was my hike up Ben Nevis.