Freeze Drying vs Dehydrating: Which Is Better For Preserving Food?

apples

If you’re a food manufacturer, then you should be familiar with the fact that your product needs to be properly preserved if you want to maintain its integrity and optimize its shelf life. And considering that food can be very finicky, finding the right preservation method isn’t the easiest task. 

Fortunately, freeze-drying and dehydration have emerged as two major channels through which food preservation can be done. In this article, we’ll look into how both processes work and the differences between them. 

Freeze Drying vs Dehydrating: What Are The Processes? 

Before we begin looking into the freeze-drying vs dehydration debate, let’s first examine what both processes are, as well as what makes them particularly unique.

What Is Freeze Drying? 

First, we have freeze drying. Some people call it lyophilization, but this is a process that is notable because it works in different fields – not just in preserving food. 

With freeze drying, you take a perishable material and freeze it to take out any moisture content. Once the material is frozen, all ice is taken out through a special sublimation process, meaning that the substance itself moves from being a solid to being a gas without having to go through the liquid phase at all. 

Freeze drying is known for its impressive reliability. You can have freeze-dried marshmallows even days after the process has been applied to them, and you can rest assured that their quality and texture will be just the same. 

What Is Dehydrating Food? 

Next on the freeze-dried vs dehydrated debate, we have dehydration. 

In many ways, you can say that freeze-drying is a type of dehydration. Nevertheless, this method focuses as well on taking out the water content of food and ensuring that the enzymes and microorganisms that cause spoilage are unable to grow. 

The reduction of this water content means that the food can last longer and that it doesn’t end up being a chore to handle. 

Freeze Drying vs Dehydrating: How Do They Work?

bananas

Next on the freeze-dried vs dehydrated debate, let’s examine both processes to understand how they work and what insights can be gained from them.

The Freeze Drying Process 

So considering that it’s become one of the most popular methods of food preservation today, there has been a lot of emphasis on freeze-drying as a process. How does freeze-drying work

Generally, freeze drying tends to operate in three phases: 

Start By Freezing The Food

First, you prepare your material and freeze it. In most cases, you’ll need temperatures of about between -40°C to -50°C (-40°F to -58°F to freeze the material. In some cases, you might need even more. 

With freezing, you take the water content of the material and ensure that it is properly solid, so no microbes can grow on it. 

Move On To The First Drying Process

Once the material is frozen, it goes through the initial drying process. Here, you get a vacuum chamber to help cut down on the material’s pressure. 

With this depleted pressure – as well as a rise in the material’s temperature – you will be able to move the ice straight from solid to gaseous form. And as such, much of the water content of your material will be sucked out. 

Complete The Drying Process

Well, you have one drying process locked down. Time to move on to the next. 

Although the first drying process takes out much of the water, you will most likely have some amounts left. The secondary drying process ensures that you can take the rest out once and for all. Those low residual water levels are really important, so you need this step for sure. 

Package & Deliver 

After your process is done, seal your material in an airtight container and store or send it out. 

How Do You Dehydrate Food? 

As for dehydration, you don’t necessarily have a one-size-fits-all approach. Like we said earlier, there are different forms of dehydration – and this means that you need to select which of the processes you actually want to work with.

To that end, let’s look into two major forms of getting dehydrated marshmallows to see how they actually work: 

The Air Drying Process

For air drying, you focus on these steps: 

  • Prepare your food items. This could be through cutting them, peeling them, or modifying them into the right pieces
  • Place the food items in racks or trays and put them in a  location where air easily rushes in and out.
  • At the same time, ensure that your food is covered, so contaminants won’t be able to get through
  • Let the food dry for as long as possible. You can keep checking to make sure they’re dry enough, then package when they do become arid. 

Drying With The Sun

This process is quite similar to air drying, but it focuses more on getting direct contact with the sun for your food. The processes here include the following:

  • Prepare our food, just as you would with air-drying
  • Let the food racks be placed in an area where the sun can get to them directly. 
  • You can spin the trays and food pieces around regularly to ensure that every part of them gets dried
  • Remember to protect them from contaminants and insects while they’re out
  • Check for dryness, and when they’re fully dried, you can package them

Making Use Of An Electric Food Dehydrator

You could also engage an electric food dehydrator – essentially, a machine that helps to bring some efficiency to the dehydration process. To make use of the machine, follow these steps:

  • Prepare your food by watching and cutting if necessary
  • Load the food onto the trays, then place them in the electric dehydrator 
  • Choose the right temperature setting. Remember to be cautious of the food type here, so you don’t overdo things
  • Let the food dry, then check it periodically for dryness
  • Once you’re good to go, let the food cool down, and you can store it properly.

Freeze Drying vs Dehydrating: Differences In Texture

berries

So we understand the freeze dried vs dehydrator processes and we can see how they work. Now, let’s compare both processes based on one of the most important things of all – food texture. 

With freeze drying, you have a process that leaves your food with an airy, light texture. You see, freeze drying takes out all the water content in your food, leaving it feeling pretty light. And with sublimation, you also get a bit of a porous feeling, leaving your food feeling crunchy and crisp.

That said, your food will hold on to its color and shape, and the flavor won’t be affected in the slightest. Since freeze-drying protects your food’s cellular structure, you’re good to go. 

With dehydration, you have varying texture levels. You might be able to achieve some uniformity if you make use of an electric dehydrator, but textures tend to vary – with most foods coming out a bit leathery and chewy as a result. 

The appearance of your food will most likely change as well, so you need to keep that in mind when choosing this method.

Freeze Drying vs Dehydrating: Quality Of The End Products 

At the end of the day, the entire point of preserving food is so that you can still enjoy its quality down the line – or when you get the food back in its natural state. So, how does the freeze dryer vs dehydrator debate work here? 

With freeze drying, you won’t have an issue with product quality. Like we said earlier, texture and flavor for your food won’t change when you freeze-dry it. And, when you consider the fact that you can easily rehydrate your food, you’ll find that there’s barely any downside here. 

The same can’t necessarily be said about dehydration. Most dehydration processes will change the texture and flavor of your food, and this means that you might not necessarily be familiar with the end product. Add this to the fact that rehydration tends to take longer – if it’s even possible at all. 

Freeze Drying vs Dehydrating: Foods That They Can Work With

Every food manufacturer wants a process that is flexible and versatile. The very last thing you want is to find out that your preservation process isn’t good enough. So, what is the difference between freeze dried and dehydrated processes when it comes to the foods they are compatible with?  

For freeze drying, you have a process that works with a bunch of materials. These include fruits and veggies, dairy products, whale entrees, and even dairy products. Whether they’re solid or liquid, they can easily work with freeze drying without fear that they will lose texture or become unsatisfactory. 

That said, you also need to be careful with high-fat foods when freeze-drying. Fried foods and certain vegetables that rely on their water content (pineapples, watermelon, cucumbers, etc.) will be affected by freeze-drying as well since the process strips them of all their fluidity.

Moving on, dehydration is also versatile. It works with fruits and vegetables, spices and herbs, powdered foods, and even snacks. However, it struggles with high-fat foods too, as well as eggs, leafy greens, and dairy products in general.

Freeze Drying vs Dehydrating: Nutritional Retention

freeze drying vs dehydrating

One major consideration for food manufacturers is the ability of the preservation process they work with to ensure that their food remains nutritious even after the treatment has been done. Otherwise, what’s the point? 

So, in the long run, which is healthier – freeze dried or dehydrated food? 

With freeze drying, you have a process that looks after the nutritional content of your food. The fact that you’re working with low temperatures means that material degradation is reduced, especially for heat-sensitive components and materials.

Everything – from vitamins to minerals and even enzymes – will be preserved via freeze drying. And when you add the fact that your food’s flavor and color will also be protected, you can see just how effective the process really can be. 

For dehydration, nutrient loss is sadly a real possibility. Heat is introduced into the mix at high levels, and this means that heat-sensitive materials such as thiamine and riboflavin can be expelled from your food. 

Changes in color and flavor are also a real possibility, especially if the food has been exposed to excessively high temperatures. So, you need to really consider what you’re working with here. 

Freeze Drying vs Dehydrating: Equipment and Cost Considerations

At the end of the day, food preservation will most likely cost you money. So, it’s understandable if you’re really considering the financial implications of your decision here.

That said, which is more cost-effective in the freeze-drying vs dehydrating debate? 

On the initial end, freeze-drying can be pretty expensive. The freeze dryers themselves are much more complex than dehydrators, with the products consisting of a vacuum chamber, a refrigerator, and tools for general heating. So, as you would imagine, the freeze-drying equipment will set you back financially more than a dehydrator., 

Besides the upfront cost, you also need to consider running costs and maintenance. Freeze-drying equipment can be very energy-intensive, especially when you get to the vacuum pump and refrigeration tools. 

Finally, maintenance is something else that makes freeze-drying equipment. Like all tools, your freeze-drying apparatus will need to be properly maintained over time, and you need to account for that. This isn’t to say that dehydrators won’t cost money too, but you tend to spend more on freeze-drying overall. 

The benefits can outweigh the costs, but you need to consider the financial factor when making a choice. 

Freeze Drying vs Dehydrating: Storage and Shelf Life

fruits

In terms of storage, there’s a clear winner in the food dehydrator vs freeze dryer debate – and that’s the freeze dryer. 

You can use a freeze dried marshmallow and eat it weeks after the process has been applied to it, and it’ll take like you just made it. This is one of the many freeze dryer benefits. But, the same can’t be said for dehydration. Because freeze-drying tends to take out the moisture content of the food, you have a higher chance of enjoying it for longer and even preserving it. With dehydrators, you might not necessarily have that benefit. 

Freeze Drying vs Dehydrating: Which Do You Choose? 

Now that we have a better handle on the two processes and what makes them unique, let’s look into the decisions you have to make when you’re deciding between them. 

Generally, you want to choose freeze drying in any of the following conditions: 

  • You want to retain as much of the nutrient in the product as possible, and you’re working with what-sensitive materials
  • You need the original texture back even after preserving the food
  • Shelf life is a major priority, and you need your food to last long. 
  • You have specialized foods that might not necessarily dehydrate so efficiently
  • You’re operating on a much larger scale and you need a process that will work for you.

On the other hand, dehydrating will be a much better process for you under the following circumstances: 

  • You’re trying to save money and looking for the most cost-effective channel to preserve your food 
  • You need a process that works fast and will be over quickly
  • Space for food preservation is limited, and you want something compact
  • You’re at home, and you just need basic preservation. 

Conclusion

When it comes to food preservation, there are so many options to choose from. But, dehydration and freeze drying have emerged as two of the standout choices. 

Remember to consider the factors well before choosing between these two. And, if you need any help, we at Sainty Tec are always here for you.

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