There used to be a time when foods were easy to sort. Pasta and cans went into the cupboard. Fresh fruit and milk went into the refrigerator, and anything that needed to be kept for longer was put in the freezer.
With new technology, though, comes a wealth of options! There’s no need to put things in the freezer to make them last, thanks to the invention of the freeze dryer. Or maybe you’ve been told about the wonders of a dehydrator, instead.
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So, freeze dryer vs dehydrator: what’s the difference? Let’s find out a little more about these two machines, and how they can make fresh food last much longer, without losing too much of its goodness.
Why Preserve Food?
Food preservation is something that humans have been looking to perfect since the beginning of time. Thousands of years ago, our ancestors may not have had freeze drying technology, but they certainly had dehydrating skills, where they simply used the heat of the sun to dry and cure foods to eat at a later time.
For those who lived in bygone days, food preservation wasn’t simply a hobby, but a life-or-death situation. Food may have been plentiful in the summer, but it needed to be kept for the leaner months, such as the winter. It was important to preserve meats, fruits, and vegetables for the less abundant times.
These days we may have the luxury of such things as refrigerators, freezers, and vacuum packs, but there’s still good reason to want to preserve our food. For one, it takes less energy. The process itself requires some energy, but the food doesn’t need to be stored inside a freezer once done.
Preparation for natural disasters is a common reason for people to freeze dry or dehydrate food, and there’s a reason it’s the way to preserve food for astronauts! Freeze drying and dehydrating foods reduce their weight while preserving them for as long as thirty years.
How does Freeze Drying Food Work?
Freeze drying is a lot like freezing in that the process involves using freezing temperatures in order to preserve food, but the result is very different.
When you freeze food, you put it into the freezer and the whole item, including its moisture, freezes solid, remaining in a frozen state until you take it out again and thaw it.
With freeze drying, you both freeze the food and remove up to 99% of its moisture. The removal of the moisture is the key difference and is the reason it lasts so much longer.
Once the food has been freeze dried, it’s then put into plastic bags and vacuum sealed, so that you’ve not only removed almost every last drop of moisture, but now there’s no air in the food, either.
You’ll notice that on most frozen products, even those kept in the deep freeze, there’ll be a use-by date. Frozen food, particularly those made from meat, will usually keep for around two to five years, but after that, it can be dangerous to eat it.
This is because while the meat itself might be fine, it’s the moisture inside it that can harvest bacteria and eventually spoil the whole item. Freeze drying eradicates this problem by completely removing the moisture. Whereas regular frozen food lasts for a couple of years, freeze dried food can survive up to a whopping 25 years!
Not only that, but once the food has been freeze dried, it doesn’t have to go into the freezer for storage. If keeping it in the freezer is your choice that’s fine, but freeze dried foods including meat and fruits can just as easily survive outside the freezer, vacuum packed and left in the pantry until you’re ready to use it.
How to Freeze Dry Food
If freeze drying’s the way you want to go, then you’ll find that the most time-efficient method is via a dedicated freeze dryer. The secret to freeze drying is the extremely low temperature, applied in a very quick time, so the food doesn’t know what’s hit it before the moisture’s removed, and the air is eradicated.
But it doesn’t come cheap. Freeze driers are an expensive piece of kit, and even though they’re a great investment, if it’s not something you want to get into seriously, you might find it’s a waste of money.
Freeze dryers are generally the kind of equipment you’ll find in a commercial kitchen as opposed to a home kitchen, although it’s not too difficult to find a home freeze dryer, despite the cost.
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Using a freeze drier is really simple, though, if you’re thinking about getting yourself one. It’s a case of chopping up the foods you want freezing, then putting them into the machine, pressing a button, and waiting for the process to finish.
If you’re on a budget, freeze drying isn’t going to be for you. There are plenty of websites that will talk you through a more basic process where you lay out your food in a tray and put it into a very cold freezer, but this isn’t the same as freeze drying.
The process of freeze drying isn’t just about the cold but the removal of air, too, which needs vacuum machinery. The freeze dryer does all of this for you, cryogenically freezing the food and removing all the air, before putting the freeze-dried food into sealed vacuum-packed bags.
What’s the Deal with Dehydration?
Dehydrating food is similar to freeze drying in that it’s a great way to preserve fresh food, but in reality, that’s where the similarities end. Where freeze drying uses freezing cold temperatures in its preservation method, dehydration uses heat.
Despite the name given to the process, dehydration does not remove as much moisture as freeze drying. While freeze drying will remove up to 99%, dehydrating will usually take around 70% of the moisture away.
Dehydrating is an easy, cost-effective way of preserving food that’s been applied for thousands of years. In hot countries, meat and fruit were dehydrated by being sliced very thinly and then left to dry out in the heat of the sun.
Dehydration is also known as desiccation. If you’ve ever bought desiccated coconut, for example, you’ll know that the process used to turn the hard, moist flesh of the inside of a coconut into the fine, dry grounds used for baking has involved dehydration.
How to Dehydrate Food
By slicing your fruit, vegetables or even meat very thinly, spreading it out on a sheet of parchment laid on a baking tray, and putting in a warm oven, you can dehydrate your own food. It can be tough to get the heat right, because after all, you’re trying to gently heat the food to dry it out, and not cook it.
While it’s best to dehydrate your food using a dehydrator that’s specially built for the purpose, it’s not difficult to dehydrate your food using some home-crafted methods without the need to shell out on a piece of equipment.
It’s recommended that meat is dehydrated at a temperature of 145 degrees Fahrenheit but that it’s cooked and cooled before you dehydrate it. Fruit and vegetables should be in the oven at 125 degrees Fahrenheit.
Everyone’s oven is different, but it could simply be a case of trial and error, so don’t give up if you don’t get it right the first time!
So, Which is Best?
Now we’ve laid out the terms in the battle of ‘Freeze Dryer vs Dehydrator: What’s the Difference?’ we’ve seen that there are vast differences between the two. But does this mean one is better than the other?
Dehydration won’t remove as much moisture as freeze drying, and because of that, the end result won’t store for as long. Not only that but dehydrating food is known to lose more nutrients, up to 50%, of the food processed in this way. On the other hand, freeze drying causes a loss of only 10% of the nutritious benefits.
Freeze drying also means that there’s no need to recook the food once you’re ready to eat it. Simply add water and go. Dehydrated food, however, once opened, will need cooking in water, which adds to preparation time. Unless, of course, you’re only looking to dehydrate fruit for snacking.
Freeze drying might be the clear winner, and you’d be right until you look at the cost. Given that freeze drying requires such a huge initial outlay, it’s simply not cost-effective for most people to even begin. A home freeze dryer can cost as much as a second-hand car.
Until the cost of freeze dryers comes down, you may simply want to stick to dehydration. After all, dehydrated fruit and vegetables are still a healthier snack than chips and candy, and even more delicious!
Whichever choice you make, you’re sure to have found an effective way to preserve the food you may otherwise have let go bad and have thrown in the trash, so making a conscious choice to preserve extra food for the future would only make your ancestors proud!