Freeze dryer and lyophilizer are synonymous names for the same equipment. A freeze dryer executes a water removal process typically used to preserve perishable materials, to extend shelf life or make the material more convenient for transport. Freeze dryers work by freezing the material, then reducing the pressure and adding heat to allow the frozen water in the material to sublimate.
Freeze-drying can be defined as one of the leading ways of keeping your food and vegetables fresh and edible for an extended period. The primary concept of freeze drying your food is to freeze it and then alter the pressure in the surrounding air. This process allows water in the food change to a gas chemical state from a solid state. You can see that the idea for food storage is similar. As water from your food transforms to solid state from liquid, it will become parish and finally acquire a gas chemical state. This action eliminates the two factors that enable bacteria to multiply, spread, and lessen the quality of your food.
The freeze drying process is also referred to as cryodesiccation or lyophilisation. The process of lyophilisation is primarily used in the food industry as it is majorly intended for transporting food on a large scale. The process makes the material compact and in an ideal state for transport. However, using this method to store food in your home is also recommended. Even if your food is frozen for a long time, this process enables it to retain its natural nutritional value.
How to Use Freeze Dryer？
Using freeze dryer is fairly simple. All you need to do is cut your food into smaller bits and chunks so that it can fit in the freeze dryer. Once you’ve done that, all you need to do is modify the temperature that you want to keep your food in, and start the process of cryodesiccation. This machine will automatically and simultaneously freeze your stored items and change its structure so that the water parishes from it. The technique was invented early in the 20th century by Jacques-Arsene d’Arsonval and his assistant Frederic Bordas. Since then we’ve found various uses for implementing this process in the food industry as well as other businesses.
What is a food dehydrator?
A food dehydrator is a kitchen tool designed for drying different types of food items. Food items are dehydrated for many purposes. The process involves removing moisture from food, and the main goal is to extend shelf life.
Bacteria can not grow in dehydrated food. Dehydrated food can be consumed in a couple of ways: eat them dry or rehydrate and cook them. It depends on the type of food. The process of dehydration usually takes a few hours. When dehydrated, fruits and other food items look very different.
A food dehydrator helps you store food throughout the year so that you can enjoy your favorite food whenever you wish. If you are a food enthusiast, you will find this tool very useful. A good thing about dehydration is that when you fruits and other food items are dehydrated, they still retain their taste and nutritional properties.
Apart from dehydrating food, a food dehydrator can be used for some other purposes. This is why some call it a multi-purposes tool.
There are many types of food dehydrators on the market, and prices vary wildly. When purchasing this tool, you have to be careful about a few things. Factors that determine the quality of a food dehydrator are components, trays and temperature level.
Dehydrating and desiccating
The process of dehydration removes moisture from food, and as a result the food can be stored in the freezer for a long time. But why does dehydrated food last long? The reason is simple: bacteria can not grow in dehydrated food.
Specific temperatures are required for the growth of bacteria. When you dehydrate food, it is no longer a breeding ground for bacteria. Thus the process extends the shelf life of your food.
Now we will try to briefly discuss the process of desiccation. By desiccating your food, you can completely remove moisture from it. Desiccated food lasts even longer, because there is no trace of moisture in it.
Dehydration is the process of transforming fresh ingredients into dry ones. Your food will no longer be fresh, but it will retain its nutritional value. For long-term storage of food, you will find a food dehydrator immensely helpful.
Differences Between Freeze Dried And Dehydrated Food
Freeze drying and dehydration are two popular ways of boosting the shelf life of food for future consumption. However, with the ongoing hyped up craze about dehydrating machines and all their benefits, it’s understandable if you are lost between storing your foods by freezing or switching to a food dehydrator.
While these two processes serve the same purpose- adding life to the food in season for consumption when that particular food is out of season- each has its own benefits and drawbacks.
To understand the major benefits and drawbacks of each of these models, it pays to have knowledge of the processes involved in both and how each of them works first.
Freeze drying is a 3-step process. It involves selecting the type of food that you want to dry and freezing it. Next, the food is placed in a strong vacuum (make use of a good vacuum food sealer). Here, the ice crystals in the food sublimate turn directly into water vapor rather than passing through the liquid state.
The food is then placed in vacuum storage bags or containers and stored either in a freezer, pantry or in an emergency kit when prepping.
On the other hand, dehydration involves using heat, dry air, and air movement to remove water from food. Dehydration can be done with or without a dehydrator.
Of course, the first consideration that should top your checklist is how good each of these methods preserves the nutrients in your food.
Freeze-drying has the upper hand at this front. Researchers suggest that since freeze-drying food involves removing up to 98% of the food’s water without the use of heat, the food tends to maintain a significantly higher nutrient content compared to dehydration.
A 2011 study published in the journal for National Institutes of Health wanted to investigate the effects of freeze-drying on the antioxidant compounds in selected fruits.
At the end of the study, the researchers reported that this method didn’t exert significant changes in the number of nutrients.
On the other hand, dehydration is known for leading to a higher loss of nutrients. This could be attributed to the fact that this process involves subjecting the nutrients to high heat (up to 140℉) and light.
For instance, some vitamins such as A and C tend to decrease once they are subjected to high heat or even air. The A vitamins are also sensitive to light. Therefore, the sun will definitely have a toll on them if you are relying on it to dry your food.
Having seen that some vitamins and minerals are stripped when dehydrating than during freeze-drying, it’s pretty much obvious that freeze-dried food tastes great.
Freeze-drying removes water only. Since it does not involve heating, the nutrients, flavors, and color of the food are left intact and remain so for quite a long time with proper storage.
Worth noting, this is what makes most nutritionist and food experts to recommend freeze-drying when dealing with herbs.
4. Use Of Additives
Another major difference between these preservation methods is the use of additives. If you are fond of buying dehydrated food from stores, then you must have realized that they have very high sugar contents. This sugary taste comes from the preservatives added during storage to extend the food’s shelf life.
On the contrary, freeze-dried food has almost 98% of its water content removed. This translates to a reduced foothold for bacteria that make food go bad. This also means that fewer (if any) additives are used.
Be advised, however, that the only way to keep off additives and preservatives from your stored food is to freeze-dry or dehydrate it at home.
This is where dehydrated foods beat their freeze-dried alternatives. As I have told you before, freeze-dried food has most of its water content removed. Dehydrated food, however, has a considerable amount of its water content sealed in.
As a result, dehydrated foods have a chewy texture and are sweet in taste. Unfortunately, remember that their taste slightly differs from that of fresh food due to the sugar, salt, and other preservatives used.
On the other hand, freeze-dried food tends to have a crispier and crunchy texture since they are virtually dry.
People are coming up with ways to freeze dry or dehydrate different types of food each day. However, it’s undeniable that freeze-drying offers a lot of options than any other food preservation method.
Freeze-drying allows you to use almost all foods ranging from high-water content to low-water content varieties. This means that you can freeze-dry not only herbs but yogurt, ice cream, cheese and fruits among others.
On the other hand, dehydration mostly favors low-water content foods. This limits you to certain meats, vegetables, and fruits such as apples.
Regardless of the method that you go for, you’ll want to rehydrate your food before consuming it. Freeze-dried foods are much easier to rehydrate than dehydrated foods. The best part about rehydrated freeze-dried food is that it’s almost similar to fresh food in all aspects. These foods also rehydrate easily and only require water (hot or cold).
Dehydrated foods are another story. These foods can be really tough and this means that rehydration won’t be a walk in the park.
While cold water can still be used to rehydrate dehydrated foods, hot water is most preferred since it speeds up the process. Beef jerky, for instance, takes up to 4 hours to rehydrate when using cold water. On the other hand, the same process could be done in utmost 30 minutes using hot water .
While the use of hot water seems more promising, it might be a huge problem during emergencies and when you are far from civilization.
8. Cooking And Baking
Basically, both freeze-dried and dehydrated foods can be rehydrated and be used in a variety of dishes. All in all, freeze-dried food offer more options in that, they don’t vary much from fresh foods upon rehydration.
Dehydrated foods, on the other hand, remain very different from fresh their fresh food derivatives. This means that the two don’t deliver the same results. You could be limited to certain dishes due to this reason.
9. Shelf Life
Freeze-dried foods still take the lead here. Dehydrated foods contain between 30-50% of their water content compared to the 2% water content in freeze-dried foods.
What this means is that while these two methods aim at extending your food’s shelf-life, dehydrated foods are more susceptible to microbial growth than freeze-dried foods.
That being said, you should expect the latter to last for much longer. In fact, experts say that freeze-dried foods could be stored indefinitely if is stored in a free-standing freezer at zero degrees Fahrenheit.
This is subjective though. Whether you are dealing with dehydrated or freeze-dried foods, minute leaks in the packaging bags, cans, or jars could lead to bacterial growth even without causing any color changes on the package. Therefore, proper care is required irrespective of the method of preservation that you go with.
10. Cost And Efficiency
Freeze-drying your food seems like the best way of preserving food until you consider the cost. This method is usually quite costly especially in terms of power. Store-bought freeze-dried foods are also considerably costlier than their dehydrated alternatives.
The presence of many dehydrator brands on the market today has brought the price of these units lower than ever before. Today, almost anyone can afford a basic dehydrator today.
In addition, these units don’t require so much power to run. Thus, you could save hundreds by dehydrating lots of food for usage when the supply is low.