Outforia Quicktake: Key Takeaways
- Freeze-dried food has a longer shelf life, better taste, faster rehydration, and higher nutritional value compared to dehydrated food.
- High costs of freeze-drying equipment make it less feasible for average homeowners, making dehydration more practical.
- Freeze-dried food lasts longer due to its lower moisture content (99% water removed) compared to dehydrated food (80-90% water removed).
- The low temperatures used in freeze-drying help preserve the food’s original texture and taste.
- Despite its advantages, freeze-drying requires electricity, is noisy, and the machines are large and expensive, which may not be suitable for everyone.
For those of you concerned with the likely apocalypse that will happen when supermarkets run out of food, look no further!
Survivalists amongst us know that if the food supply chain is broken, there is only enough food in the supermarkets for three days.
Freeze-dried food has a longer shelf life, tastes better, rehydrates faster, and keeps its nutritional value better than dehydrated food. However, the high costs of freeze-drying equipment mean dehydration is more practical for the average homeowner!
Why Do I Need Freeze-Dried and Dehydrated Food?
There are many reasons to use dehydrated or freeze-dried food. Most often, these reasons come up when you’re on a long trek into a wild place. Or perhaps, you’re going on a long road trip.
You likely have no means of refrigeration on your journey. You also need to keep your pack weight down. It’s possible that you’re going to be blasted by hot sun and/or buffeted by winds and rain on the way. And you’re worried your camp may be scavenged at night by animals.
Your food supply needs to withstand all this and more.
Freeze-dried and dehydrated food is light, long-lasting, and mostly odorless (unless taken out of the packet). It does not decay for years.
What Is Freeze Drying and How Is It Done?
Freeze drying is also known as lyophilization. It’s when food is chilled to a very low temperature, around -40C. It then has all the moisture sucked out of it. This is called vacuum drying.
It was first invented in 1906 by a Frenchman, Jacques-Arsene d’Arsonval. Freeze drying was used to preserve blood serum during WW2. NASA also used freeze drying for a lot of their astronaut rations, including their popular ice cream!
Here’s how freeze-drying is done:
- Chill food to well below 0F.
- Primary drying (sublimation)
- Secondary drying (desorption)
Sublimation is when a solid is turned straight into a gas without going through a liquid phase. So this means the ice in the food turns straight into water vapor. This preserves the texture and taste as well as the nutrition content.
Desorption is when all the moisture and water vapor is sucked away from the food with a vacuum pump.
You cab check out this video to learn how freeze drying works:
What is Dehydration?
Dehydration is simply the process of removing moisture from food. This is most often done with heat. Although it’s possible to use another method, such as adding gas to push out the moisture.
This isn’t the same as pressing liquid out of the food mechanically.
Historically, people used the sun to dehydrate foods. Think sun-dried tomatoes or American Indian pemmican. Pemmican is made of dried meat mixed with berries and animal fat. Beef jerky is similar. For a pemmican recipe, scroll down this page.
Check out this tutorial on how to make homemade Italian Sun-Dried Tomatoes:
How Can I Make Pemmican?
Pemmican was first made by First Nation peoples in America as trail food. It’s very high in energy and contains vitamins from the added berries. Pemmican will keep you going indefinitely in a survival situation.
It’s not a good option for vegans or vegetarians, however!
I first made a version of pemmican out of bacon fat, bacon, raisins, and porridge oats on my Mum’s cooker when I was 11. I made an awful mess but I proudly ate every bit of it as I trekked the hills behind our town.
You will need:
- Cut the meat into thin strips. Rub it with salt. (1 tsp or 5.7 grams of salt per pound or half kilogram of meat)
- Dry the meat. Use an air drying rack as the Indians did, or a dehydrator! You can also freeze-dry it if you’d like.
- Dry the berries.
- Grind the meat and berries into a dry powder. To avoid clogging, make sure they’re so dry that they crack before you put them in your mill or grinder.
- Add to the fat in a ratio of fat/meat and berries of 1:6.
- Roll into bar shapes and store in grease proof paper/plastic tub with a lid. Keeps for years!
Freeze-Dried is Best
In most situations, freeze-dried food is a better option than dehydrated food.
Longer Shelf Life
Freeze-dried food lasts longer as it has a lower moisture content. Freeze-dried food has around 99% of the water removed, whilst dehydrated food has 80-90%. So, dehydrated food will spoil at around the 5-10 year mark. Freeze-dried will last for 15 to 20 years. You could even hand it down to your grandkids!
Better Taste and Texture
Freeze-dried food tends to keep its original texture and taste. This is due to how the food is chilled to very low temperatures before being dried. This locks in nutrients, which also makes the food taste as good as it did before.
Shorter Rehydration Time
Dehydrated food can take 20 minutes to rehydrate back to its previous form and tastiness! Meanwhile, freeze-dried food takes only 5 minutes.
Better Nutritional Value
Freeze dried food keeps 97% of its previous nutritional value. Dehydrated food keeps only 60% of its nutrition. As we said before, this is due to the low temperatures of the freeze drying locking in vitamins and other goodies.
The Cons of Freeze Drying
There are some cons to go with the pros of freeze-drying foods.
The high cost of freeze-drying equipment means it is out of the reach of many people with an average budget.
Freeze drying machines can cost upwards of $2,595. Some can cost $3,595!
There’s also the cost of the mylar vacuum bags with oxidizers to store the food in, at around $24 for 60. Plus there’s the cost of the vacuum pump oil. This can vary, but it is roughly $20 a gallon.
Now you need to factor in the rising cost of electricity…
Needs Lots of Electricity
You will need lots of electricity to freeze dry your supplies. No electricity, no freeze drying! Which means if you’re out in the sticks, or in an apocalypse situation, (or if you run out of money for electricity) you are going to need to dehydrate stuff instead!
Of course, you could run it off a portable generator. But you might want to save that valuable fuel for other things.
The freeze drying machine is quite noisy. At 62 to 67 decibels it’s only a little bit quieter than a vacuum cleaner. So, if you’re trying to survive undercover in a post apocalyptic world, dehydrating is, by contrast, nice and silent!
Lack of space
Freeze drying machines are not small or light.
A medium-sized freeze drying machine is 20″ x 25″ x 30″ (50 x 63.5 x 76.2cm) and weighs 212 pounds (96kg). It also can’t sit on the floor – it needs to be raised up. A large machine can weigh 253 pounds (114kg) and measure 22.5″ x 25.5″ x 32.5″ (57 x 63.5 x 81.2cm).
Are Electric Dehydrators Good?
This depends on whether you want an electric dehydrator, or one that uses renewable energy (usually the sun!). Do you want to be reliant on the grid or on generator fuel? Do you want to be self-sufficient?
Or do you just want to dehydrate food quickly for a trip into the outdoors?
What Is an Electric Dehydrator?
These dehydrate food faster than a solar powered dehydrator as they don’t rely on weather. However, you will need to factor in reliance on electricity. If you are solely interested in preparing food for camping and hiking trips, and don’t have a lot of time to prepare, these are for you.
Here are some things to consider before buying an electric dehydrator:
- Amount of space and how many shelves – if you want to dehydrate large amounts of food, choose a model with 6 trays or more!
- Timer length – a 12-hour timer is okay for most food, but things like herbs take longer. Choose a model with a 24-hour plus timer if you’re going to dry herbs or other greens.
- Accessories – check for mats to catch drips if you are making things with a lot of liquid.
You may also like: Food To Take On A Hike: Top 10 Trail Snacks
What Is a Solar Dehydrator?
A solar dehydrator is a disaster-proof but slower alternative to your usual dehydrator. These are cheap and very simple. You need to keep off rain and hungry animals such as rats and birds. Hang your food up high to stop rodents. Put a net over it to protect it from birds.
Can I Make My Own Solar Dehydrator?
Yes, you can, if you have the time and are reasonably handy with tools! Some of my favorite foragers (such as Mark Williams of Galloway Wild Foods) and backwoods people have made their own solar dehydrators.
You will need:
- Timber for the frame
- Metal sheets painted matte black
- Mesh screen for food
- Polycarbonate/glass/perspex for the sunlight to come through
- Screws, drill, saw, nuts.
Here is a great link for a DIY solar dehydrator project. Make sure you build it in a sunny place!
You may also like: Are Solar Cookers Worth It?
What’s the Best Dehydrated Camping Food?
As for dehydrated one-meal packets, here are the best in show right now.
- Firepot – Although these have a long rehydration time (15 mins), they are tasty and have a good variety of meals. They also have a long shelf life.
- Tent Meals – These pack down small and light, but are still filling. They are vegan and are well-flavored with spices!
- Huel – It may not be the tastiest, but it’s great for sharing a meal. They come broken up into ingredients which you then add to everyone’s bowls, just as they like it. It’s a bit tedious to prepare, however.
You may also like: The Best Camping Food: No Cooking, No Refrigeration
How Do I Make Dehydrated Fruit Leather?
Fruit leather is a great way to break into the art of dehydration. Aside from being tasty, it’s full of energy and vitamins. Almost everyone likes it, as I have found when making it for my foraging courses. It can be eaten as it is, with no preparation.
Things you need:
Steps on making dehydrated fruit leather:
- Take equal amounts of fresh fruit and pectin rich fruit. Chop them up.
- Add to the saucepan and add enough boiling water to cover.
- Boil, then simmer until the fruit has softened.
- Mash the mixture with the potato masher.
- When it is the consistency of stew, push the mixture through a sieve to get rid of pips.
- Return to the cleaned saucepan and add the sugar or honey.
- Stir until the sugar/honey has dissolved.
- Spread the mix thinly on a sheet of baking paper or on a wet food tray insert in your dehydrator. It needs to be about 0.3cm (0.1in) thick.
- Turn on the dehydrator. Or, do what I do: stick it on the bottom shelf of a very low oven at gas mark ¼ or ½.
- Leave for around 7 hours in the oven. Keep checking it after 5 hours. When the surface of the leather is rubbery to the touch, turn off the heat.
- Cut into 3cm (1.2in) wide strips and roll them up. Delicious fruit candy which is actually good for you! Fruit leather will last for around a year if properly dehydrated and stored in an airtight container.
You may also like: How To Keep Food Cold While Camping
Freeze-Dried vs Dehydrated FAQs
Can I freeze dry meat?
Yes, you can freeze dry meat and fish. The freeze drying process works just the same. As with all freeze-dried foods, make sure the end result is bone dry before storing. You can freeze dry both raw and cooked meat and fish.
Are there any foods that can’t be freeze dried?
Peanut butter, syrup, honey, pure chocolate and butter don’t freeze dry well. Thankfully, these foods store well, or even preserve other foods anyway.
Can I freeze dry dairy products?
You can freeze dry most dairy products, including raw and cooked eggs, buttermilk, and cheese as well as ice cream. Butter is the only dairy product that does not freeze dry well.
How long does it take to freeze dry food?
It depends on the moisture content of the food. Very juicy things like pineapple can take 45 hours. An average time is 20-40 hours.
Is dehydrating food easy?
It’s possible to dehydrate food on brown paper on top of a cupboard, or in drying racks made of hessian or other natural material. You can do it with a metal rack on top of a stove. Or hang food like fungi by threading it with strong thread and hanging it in a warm dry place. Things don’t need to be complicated!
Can I dehydrate all foods in direct sunlight?
Foods such as greens and herbs are better dried in a warm dry place OUT of direct sunlight. The sunlight will discolor them and can take the taste away.