Cutting costs by minimizing food waste is a goal for both households and businesses. One of the ways to do so is by different food preservation methods. Preparing freeze-dried fruits or candy is an increasingly popular food trend. The process not only increases their shelf life by decades but also gives them a crunch texture. Freeze-drying machines can be used not just for food but for beverages too. Dehydrating coffee or milk will turn them into powder. Freeze-dried drinks can be mixed with water and turned into a tasty beverage once again. In this article, we’ll explain how freeze dryers work and what are the main types on the market. We’ll also share more information about their applications and the most popular freeze-dried food products.
How a Freeze-Drying Machine Works
When comparing freeze-dried vs dehydrated products, there are various differences. For example, simply dehydrating food can be done in an oven or an air fryer. However, in order to freeze dry, you need a specialized machine. Let’s see what are the main stages of this process.
Stage 1: Freezing
After the products are placed in the freeze-drying machine, the first step of the process is to freeze them. The machine lowers the temperature to roughly 0 °F. At that temperature, water molecules turn into ice. Products that have a lower melting point or a lot of fat content instead of water can’t be freeze-dried. Examples of such products include alcoholic beverages or fruits like avocado and coconut.
Stage 2: Vacuum
After the items are frozen, the machine creates a vacuum through a pump. By reducing the pressure, sublimation can be achieved. That is a state in which the water molecules will evaporate instead of liquify because of the reduced pressure.
Stage 3: Drying
The main drying process occurs after the pressure has been reduced. It’s done by slowly heating the products. This causes water molecules to turn into vapor without melting. The vapor condenses in a collector and can be removed after the freeze-drying machine has finished the cycle. The drying process removes roughly 99% of the water from the products. The reduced water content stops bacterial growth. That’s why wholesale freeze-dried products can safely be consumed years after they’ve been dehydrated.
Stage 4: Storage
Even though this step occurs after the products have been taken out of the machine, it’s a very important one. Whether you’re making freeze-dried candy or dehydrating herbs to get tea varieties and blends, they should be stored properly. If the products are exposed to moisture, they can begin rehydrating which will lower their shelf life. If you plan to find suppliers of freeze-dried products make sure they give you proper storage instructions.
Key takeaway: Unlike other dehydration methods, freeze-drying can be done only with a specialized machine. There are both home and commercial freeze dryers. The main difference between the two is their capacity. Freeze-drying machines are used by other industries like the biotech and pharmaceutical industries.
Types of Freeze-Drying Machines
Home Freeze Dryers
These machines are suitable for households and small businesses. The smaller models allow you to dehydrate around 5 pounds of products. Large home freeze dryers are available as well. They can freeze-dry around 20 pounds in one cycle. These smaller machines can still be used by businesses. In fact, they can also assist in a restaurant’s marketing efforts. As healthy freeze-dried snacks are becoming trendy, a restaurant can use a small freeze-dryer to make desserts or small complimentary meals.
Commercial Freeze Dryers
These machines can often be seen as part of a restaurant’s technology and appliances. Other businesses that frequently freeze-dry products in small or medium quantities might also purchase a commercial freeze dryer. Their capacity is between 20 and 100 pounds. These machines are also suitable for small to medium eCommerce businesses that sell various freeze-dried products like flowers or herbs.
Industrial Freeze Dryers
When it comes to large capacity, there are freeze-drying machines that can handle thousands of pounds of products. These machines are used in the beverage industry by manufacturers of instant coffee or powder mixes.
Applications and Uses of Freeze-Drying Machines
The freeze-drying method is still relatively unpopular. The reason behind this is the fact that freeze dryers are expensive. This dehydration method is used mostly by businesses and you will rarely see a household that has a freeze-drying machine. Nevertheless, the prolonged shelf life of these products and the minimum effect on their structure make it a popular technique. Let’s see some of the main uses of freeze dryers.
- Food preservation. There are various methods designed to preserve food. However, most of them increase the shelf life of products by a few months or years. Freeze-drying prolongs it significantly. And it doesn’t require the items to be kept in a freezer or another energy-consuming machine.
- Reduction of storage and transportation costs. As products are dehydrated, their weight is reduced. This lowers transportation costs. Furthermore, most freeze-dried items become less bulky. Therefore, storing them is also easier.
- Freeze-drying in biotechnology. Pharmaceutical companies often use the method to prolong the expiration date of certain products like vaccines and other injectables. Some probiotics and other pills are also prepared by freeze-drying microorganisms.
- Taxidermy. The freeze-drying method is also used to preserve animals.
- Recovery of water-damaged items. Historical documents and other items can also be freeze-dried in order to completely remove water molecules from them. This method is suitable only for certain types of paper and materials.
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Frequently Asked Questions about Freeze-Drying Machines
Since freeze-drying is a fairly unpopular food preservation method, you might have a lot of questions regarding these specialized machines. Below we have answered some of the common questions on the topic of freeze dryers.
What’s the Power Consumption of a Freeze-Drying Machine?
Freeze dryers consume between 1000 and 2000 watts per hour. The power consumption depends a lot on factors such as the size of the machine and its model. Small and medium appliances from that category have the lowest power consumption. Large ones consume around 1400-1600 watts per hour. Professional freeze dryers that are used by manufacturers and in the industrial sector can have a much higher power consumption. With the current price of electricity, that means a full cycle of freeze-drying with a medium to large device will cost you around $10.
How Long Does It Take To Freeze-Dry Food and Beverages?
It takes between 20 and 40 hours for a freeze-drying machine to completely dehydrate products. The time depends on factors like the type of products and their quantity. It’s important to properly prepare the products before putting them in the machine. Large items like pumpkin or watermelon should be sliced. The same is true for meat or cheese.
Modern freeze-drying machines have additional features such as an alert when the products are ready or reduced power consumption.
How to Choose a Freeze Dryer?
The main factors that need to be considered when picking a freeze-drying appliance are how often you plan to use it and how many goods you want to freeze-dry at once. For a household appliance that will be used once or twice a month to realize healthy snack ideas, a good option will be to pick a small freeze-drying machine. On the other hand, business owners who want to prepare freeze-dried fruits or other products should invest in a large machine that can dehydrate hundreds of pounds in one batch.