One of the best ways to store your food is to dry it with a freeze dryer or dehydrate it, but what is the difference between these two preservation methods?
For as long as humans have stored food, dehydration techniques have been a key survival strategy to prevent food shortages. However, over the years, the process of traditional food dehydration has been revamped due to freeze-drying technology.
The differences between dried vs dehydrated foods are that dehydrated foods have higher moisture content, lower shelf-life, diminished nutritional value, as well as altered flavor and texture. In addition, professional freeze-dried goods are more versatile and can be rehydrated.
Food storage is a growing trend around the nation - and for good reason. Recent events in society have reminded us of how important it is to be prepared for unforeseen circumstances and to expect the unexpected - with a food stockpile at home being a fundamental survival strategy. When planning out a food storage system, you want to put a key focus on having dry food around the house, as these are the most reliable goods that you can keep in your stockpile. However, it is important to understand that there is more than one type of method for drying food. When you shop for dry food items, you will likely see them advertised as either freeze-dried or dehydrated. While both of these food drying classifications involve removing moisture from food, there are some key distinctions that you should be aware of. Let’s take a closer look at the differences between dried vs dehydrated foods in more detail.
After extensively researching food storage methods, I have been able to gather enough information to determine the differences between dried vs dehydrated foods. My research has indicated that although both methods remove moisture from food, the process in which they do so is quite different and can affect how well food is preserved.
What Are Dried & Dehydrated Foods?
Before diving into the differences between these two food drying methods, we must understand that the main principle behind drying any food item is to preserve it and maximize its shelf life.
Food lasts considerably longer when it has less moisture content, which is why food drying techniques have been utilized by humanity for thousands of years. Moisture encourages bacteria to spread and for food to spoil. However, the technology behind drying foods has been greatly improved over the years - with new and improved air drying and freeze-drying machinery becoming standardized.
We have been dehydrating food for over 14,000 years and it is considered to be one of the first methods for food preservation. This food storage technique was introduced with sun-drying foods.
By leaving food out on trays, moisture is naturally removed and the shelf-life of goods is extended. Sun-drying can add as little as several weeks to several months onto the shelf-life of food items.
However, with modern dehydrators, the process is optimized and the expiration date of food can be pushed back even further. Food is generally dehydrated between 95°F and 165°F. During this process, roughly 80 to 95% of the moisture is removed from the food item.
Dried food or freeze-dried food goes through a much more complex drying process compared to dehydrated food. While dehydration techniques for food have been around for a long time, freeze-drying was only introduced during the 20th century - with the technology really taking off in the 1940s.
Freeze-drying is usually something that is done at an industrial level, as it requires large, high-tech equipment that is expensive to buy and can be challenging to operate. The most ‘affordable’ freezer dryers that you can buy usually start at around $2,500 to $5,000 for a basic setup.
When food is freeze-dried it is generally frozen below -40°F. Once frozen, the food vacuum chamber will remove moisture from the food item by raising the temperature slowly and forcing the water content to skip the liquid state and become gaseous. This process removes up to 98% of the moisture inside the food.
Differences Between Dried Vs Dehydrated Foods
As we have just covered, freeze-dried and dehydrated foods are both similar given that moisture is removed from the food. However, the process in which this is achieved is completely different, which is why there are some key distinctions that you should be aware of when evaluating dried and dehydrated foods.
Moisture content is the most important characteristic to consider when deciding between freeze-dried or dehydrated foods. Given that moisture is what encourages bacteria, mold, and yeast growth, you ideally want to select items that have as little water content as possible.
When food is freeze-dried, 99% of the moisture is removed. Whereas dehydrated foods will typically only remove between 80 and 95%. Although a 5% difference may not seem like a whole lot, it can make the difference between a product lasting several years and several decades.
Freeze-dried foods will last considerably longer than goods that have simply been dehydrated. The shelf life of freeze-dried foods is generally at least 10 to 25 years. This makes it more reliable when planning a food storage system.
The pro-longed shelf-life also implies that freeze-dried foods do not need to be rotated like dehydrated foods. Dehydrated foods that have not been vacuum sealed, will usually only last several months or for upwards of 1 year.
Dehydrated foods will need to be rotated to ensure that you always have safe and reliable goods stored. Whereas dehydrated food can be left without needing to be rotated or managed nearly as much.
Nutrients are a key factor to evaluate when deciding between freeze-dried and dehydrated foods. Although the nutrient value in both of these preservation methods is quite high, freeze-drying is still a much better method.
The reason for this is that the moisture of dehydrated foods is removed by using heat. When food is heated up, nutritional value starts to diminish, which often results in the removal of key vitamins.
Freeze drying, on the other hand, does not remove any of the nutrients from the food given the absence of heat in the process.
Regardless of how you store your food, it should still taste good when it’s time to eat it. The flavor of dehydrated food will change from its original taste. There will be a major flavor difference with dehydrated foods that can be a major issue for some and insignificant for others.
This is caused by the drying process which utilizes heat to remove moisture. With that being said, the flavor of freeze-dried foods will taste more similar to the original product.
The original texture of the food item will change for both dehydrated and freeze-dried goods. Given that moisture is removed with each food preservation method, you can expect there to be a considerable difference in texture - with dryness being a characteristic of both.
However, dehydrated foods will have a more chewy texture, which is particularly the case with dried fruit and jerky. Whereas, freeze-dried food items will be much more crispy.
Dehydrating foods is a lot easier compared to freeze-drying given that the equipment required is much more accessible. Humans have been dehydrating foods for thousands of years with simple sun-drying techniques.
These days, even dehydrators are a common kitchen appliance in many people’s homes. Freeze-drying is usually only done in commercial kitchens and on an industrial scale, given that the equipment is much more advanced, bulky, and expensive.
One of the best things about freeze-drying foods is that you can re-hydrate them. If you like the texture and taste of your food more when it is in its original form, you can always add water back to the item so that its moisture content can replenish.
By doing so, re-hydration will occur and the food will start to resemble its original form. Dehydrated foods, however, cannot be re-hydrated and will usually become mushy. Although you can mix certain dehydrated foods with water to improve their flavor, they cannot be re-hydrated and brought back to their original state.
The bottom line is that freeze-drying is much more versatile compared to dehydrating. You will find that only certain goods can be dehydrated with the most popular options generally being meat, fruit, and grains.
Whereas you can freeze-dry just about anything. The only things that you cannot freeze-dry well are going to be food items that have a lot of fat and sugar content. This opens up a lot of possibilities for preserving an expansive variety of foods that you would never be able to achieve with traditional dehydration techniques.
About THE AUTHOR
I have over a decade of experience in food and beverage management, including a ServSafe food safety qualification. As part of this qualification, I have been professionally trained in safe food storage.Read More About Mark Walker