16 Commonly Asked Questions About Freeze- Drying

16 Commonly Asked Questions About Freeze Drying

Table of Contents
Table of Contents

Over the past few years, most of us have heard the term freeze-drying. We understand that it’s a way of preserving food. But why has it become so popular in the last few years?

Freeze drying has become a popular alternative because it can extend the shelf life of freeze-dried foods for up to 25 years, allows you to rehydrate freeze-dried foods, and, most importantly, retains 97% of the nutritional value of the original food items.

Despite the clear benefits of freeze-dried items, freeze-dried products were hard to come by. That was until the Harvest Right Freeze Dryers came along. Harvest Right pioneered the at-home freeze dryer so that people could use freeze dryers for their own purposes.

Yet, many people don’t know what the process entails or how it’s different from other food conservation methods. 

So, if you want to learn more about the freeze-drying process, you’ve come to the right place. In this article, we’ll cover a few FAQs of freeze drying to explain what happens. 

Freeze Dryer Machine

1) What Is Freeze Drying?

Freeze-drying is a common preservation method that can keep meals fresh for an extended period. To help you understand that, we need to take a look at how food goes bad. 

Typically, spoilage is a result of microbial growth. Bacteria and fungi will attach to the food and break it down from the outside in. 

Yet, these microorganisms need water to grow and multiply. For that reason, to ensure they don’t survive, we have to reduce the moisture content of the food. 

The obvious solution is to heat up the meals until the water evaporates. 

However, this can diminish the nutritional value of the grub. Luckily, that doesn’t happen with freeze-drying.

That’s because this method relies on cooling the food until the water inside crystalizes. So, you won’t need to worry about breaking down volatile chemicals like vitamins and antioxidants. 

freeze dried ice cream

2) How Does Freeze Drying Work?

As you can guess by the name, the process involves a freezing step and a drying stage. The freeze-drying process involves a 3-step approach to complete. The entire process takes about 24-48 hours to complete. Below are the steps:

Step 1: Freezing 

The first step of the process involves rapidly cooling down the food. The temperature of the machine is cooled down to -112°F (-80°C). This will cause the water inside to freeze and crystalize. 

Step 2: Primary Drying (Sublimation)

In this step, we place the food in a vacuum chamber. That’ll reduce the boiling point of water, which will allow it to sublimate. This means it’ll change from solid to gas without turning into a liquid first. 

Step 3: Secondary Drying

In the third step, the food goes through a secondary dehydration step, desorption drying. This step works by exposing the sublimated item to temperatures as high as 122°F for a period of time. This should effectively remove 95-99% of the moisture in the item. 

freeze dried eggs

3) Advantages of Freeze Drying Food

Some of the many advantages of freeze-drying food items are:

  • Extended Shelf Life: This preservation method will significantly extend the shelf life of food items. The shelf life depends on the type of food and its fat content. However, it is common to be able to extend the shelf life of some foods to 25 years.
  • Simple Storage: Since freeze-dried foods can be preserved at room temperature, you won’t need to use refrigerator space. Plus, after removing the water from food, it’ll become considerably smaller and lighter. 
  • Cleaner: When foods are freeze-dried food, you are less likely to spill them. And if you do, it can be cleaned up much easier and faster.
  • Retains Nutritional Value: Unlike other preservation methods, freeze-drying maintains the nutritional value of the food. Because of that, you’ll get the same vitamins and minerals you would from fresh meals and enjoy better-tasting food.

4) Disadvantages of Freeze Drying Food

While freeze-drying can be beneficial, it has its fair share of drawbacks. Some of the disadvantages of freeze-drying food are:

  • Expensive: An at-home freeze-drying machine can be costly, costing upwards of $1,000. And if you decide to purchase freeze-dried foods, they tend to be more expensive than regular food because the cost of production is quite high. Lots of energy is needed to carry out the process effectively. 
  • Changes Texture: Removing the moisture from the item alters the texture and consistency of the item. This will result in crunchy textures that aren’t ideal for sensitive gums or teeth. Fortunately, you can rehydrate the food, but the texture will be a bit leathery and chewy. 
  • Not all foods are freeze-dry friendly: Although most foods can be freeze-dried, there are some types of food that cannot be freeze-dried. This primarily includes foods with high-fat content and sugar content, like nut butters, syrups, jams, bacon, and pure chocolate.

freeze dried strawberries

5) What Are the Best Foods to Freeze Dry?

Freeze drying relies on reducing the moisture content of food. So, any consumable product that contains water should be ideal for this process

Yet, some meals will maintain their color and flavor better than others. For example, fresh fruit and vegetables are high in moisture content, making them ideal candidates for freeze-dryingFreeze-dried fruits and vegetables also rehydrate well when placed in water.

You’ll be able to preserve produce like strawberries, potatoes, avocados, apples, and tomatoes. All of these should taste amazing even after freeze-drying. 

That way, you’ll have these ingredients all year round, regardless of the season. 

freeze dried yogurt drops

6) What Types of Food Can I Freeze Dry?

With the right freeze dryer, preserving almost any type of food should be a cakewalk. We’re not just talking about fruits and vegetables. Some of the food items that can be freeze-dried are:

You can even freeze-dry full meals. For instance, lasagna, beef stew, casseroles, and mac and cheese all freeze dry beautifully. 

That means you’ll be able to carry around these messy foods without worrying about spilling. 

Some people even use this conservation method with lobster, pulled pork, and even ice cream. Other than that, you can preserve herbs and spices. 

7) Which Foods Cannot Be Freeze-Dried?

Freeze-drying works by decreasing the water content of meals. Sadly, this is always enough to keep the food fresh. 

Some food types that have high-fat content and high sugar concentration won’t benefit from freeze drying. Bacteria can still grow on these foods, even if you take out all the moisture. Some food items that cannot be freeze-dried are:

  • Butter
  • Honey
  • Jams
  • Mayonnaise
  • Nut Butter
  • Nuts
  • Pure Chocolate
  • Soda
  • Syrup

freeze dried caramel apples

8) When Was Freeze Drying Invented?

While freeze-drying may sound like a contemporary term, the practice has been around for hundreds of years. 

We can trace the earliest example of this to the Inca Empire. Back in the 13th century, people would expose potatoes to below-zero temperatures on mountain peaks. 

Then, they’d use the sun to dry out the vegetables. 

Although, it wasn’t until the 19th century that modern freeze-drying came about. 

At the time, Richard Altman, a German pathologist, used the technique to preserve tissue samples from both animals and plants. 

freeze dried milk powder

9) How to Rehydrate Freeze-Dried Food

For the most part, you can eat freeze-dried meals as is. Yet, some people have trouble chewing the tough, dried-out food. 

If that’s the situation, you can simply rehydrate the consumables. 

Ideally, you should follow the guide that comes on the packaging of the food. This will give you specific instructions on what to do. 

However, if you freeze-dry the food at home, you won’t have any guidelines to follow. In that case, you can use a general rule of thumb. 

Typically, to rehydrate freeze-dried meals, you need to add one part water to one part dried food. Then, let the consumable rest for about 15 minutes to absorb the liquid. The warmer the liquid, the faster it will absorb into the dried food.

freeze dried edible flowers

10) What Can You Freeze Dry Besides Food?

Freeze drying is an exceptional preservation method that works on more than just food. For example, you can use the technique to keep coffee grounds fresh for months. 

In addition, items like shampoo, paint, and flowers are often freeze-dried to be preserved.

Plus, it has many other uses in various fields. For starters, some scientists rely on freeze-drying to conserve tissue samples. 

That allows them to study the specimens for an extended period. 

Other than that, in World War II, doctors freeze-dried blood bags. That way, they were able to give soldiers transfusions on the battlefield without worrying about it coagulating. 

Finally, we can use freeze-drying to preserve certain medications. 

11) How Much Power Do Freeze Dryers Need to Use?

The energy requirements of a freeze dryer will depend on the type and size of the device you use. For a small or medium gadget, you’ll need about 990 to 1,210 watts of power per hour. 

Moving on, a large freeze dryer will need more energy. Generally, it’ll consume around 1,500 watts per hour. 

Finally, with an extra-large device, the power rating is closer to 1,600 watts per hour. 

Note: When operating an at-home freeze dryer, the machine may need to be operating for 24-48 hours for each use, so it may raise your electric bill considerably.

freeze-dried meat

12) What Is the Shelf Life of Freeze-Dried Food?

When stored properly, the shelf life of freeze-dried food can be 25 years. However, the shelf life of freeze-dried foods can change based on a couple of factors. For starters, the manufacturer will play a major role. 

Depending on what dryer they use, the shelf life will be slightly different. That’s why it’s crucial you pay attention to the expiration date on the packaging. 

Other than that, how you store the food will affect longevity. If you place it in an airtight container with oxygen absorbers and away from moisture, light, and heat, it can be preserved for a long time. We suggest using mylar bags or food-grade storage buckets.

Once opened and exposed to the elements, freeze-dried food will go bad after about a month. 

13) How to Freeze Dry Food at Home?

The easiest and best way to freeze dry food at home is through using a Harvest Right freeze-dryer machine. Harvest Right is a pioneer in the freeze-drying space as they were able to make a professional freeze dryer that can be used at home. Yet, this device can be incredibly expensive for most people. Harvest Right does provide discounts on major holidays such as Black Friday, Christmas, Labor Day, and the Fourth of July.

freeze dried caramel

14) Freeze Dried vs. Dehydrated Food: What is the Difference?

Freeze-dried and dehydrated foods have much in common, but overall, freeze-dried foods provide more benefits. Freeze-dried foods have a longer shelf life, retain more nutrients, and provide richer flavor.

The main downside of freeze-dried food items is the higher cost. Usually, freeze-dried foods cost more than dehydrated foods because they require more energy to produce.

Below is a table comparing the main differences between the two.

Freeze DriedDehydrated
PriceMore expensiveMore affordable
Shelf LifeUp to 25 yearsUp to 10 years
NutritionRetains 97% of nutrientsRetains 60-70% of nutrients
TasteRicher flavorStrong Flavor
TextureChewy, Crunchy, PowderyHard, Brittle

15) How to Store Freeze-Dried Foods?

Before getting into how to store freeze-dried foods, you should understand why freeze-dried foods go bad in the first place. Food spoils when it is exposed to oxygen, heat, light, moisture, or pests. So, to ensure your freeze-dried foods can reach their maximum shelf life, they need to be protected from these environmental aggressors.

When preparing to store freeze-dried foods, you should aim to keep the food items in an airtight container with oxygen absorbers. Mason jarsmylar bags, or food-grade buckets are good choices to protect food items against oxygen, moisture, and pests. Afterward, you should keep the container in a dark place with a steady temperature that is consistently below 75°F (24°C).

Simply taking these points into consideration will let you store your freeze-dried foods for up to 25 years.

freeze dried fruit

16) What is the Ideal Freeze Dried Food Storage Temperature?

The ideal temperature to store freeze-dried food is 60-75°F (16-24°C); however, it can. The most important thing is to store your food in a place where the temperature is consistent year long.

Freeze-dried foods can be kept in a freezer, but it is not necessary. At room temperature, freeze-dried foods can be stored for up to 25 years.

Also, many people think storing freeze-dried food in a garage is safe, but it is not. This is because the temperatures in a garage swing drastically depending on the weather outside. So we advise against storing food there.

Freeze Dried Herbs

Conclusion

Freeze drying is one of the best food preservation methods available today. It works by removing water from meals, without affecting their composition and is able to significantly extend the shelf life of most foods. 

To do that, the process relies on cooling the food and then dehydrating it in a vacuum chamber. 

As a result, your consumables are able to be stored for long-term storage while maintaining their nutritional value.

If you found this article helpful, consider reading our related articles on Soulful Prepper. If you have any further questions, feel free to contact us.

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