Freeze Dried Vs Frozen: What’s the difference?

on July 17, 2023

Two common techniques—freeze-drying and freezing—have established as leaders in the field of food preservation. These methods have completely changed how we prepare and consume our favourite foods, each with their own benefits and drawbacks. What distinguishes frozen foods from those that have been freeze-dried?

Food can be preserved in two different ways: freeze-dried or frozen, each of which has unique properties and procedures. The following are the main variations between frozen and freeze-dried foods:

Process: Food must first be frozen at extremely low temperatures before being placed in a vacuum chamber to complete the complicated process of freeze-drying. Bypassing the liquid stage (sublimation), the frozen water content in the meal is transformed straight into vapour in this chamber. However, freezing only entails bringing food’s temperature down to below its freezing point in order to stop microbial growth and enzymatic activity.

Water Content: Food that has been freeze-dried often has a lot less water than food that has been frozen. Up to 98% of the water content can be eliminated during the freeze-drying procedure, leaving behind a light, dried product. In contrast, though in a solid form, food that has been frozen keeps its inherent water content.
Shelf Life: Food that has been freeze-dried has an incredibly long shelf life; it frequently lasts for months or even years. By removing the water, you can reduce bacterial growth, enzymatic reactions, and food rotting. Because of the risk of freezer burn and the potential for quality deterioration over time, food that has been frozen has a comparably shorter shelf life while still maintaining its freshness.
Nutritional Value: Food’s nutritional value is known to be preserved through freeze-drying rather than freezing. Both processes have the potential to result in a negligible loss of nutrients, however freeze-drying often retains more vitamins, minerals, and antioxidants. Even though freezing effectively retains some nutrients, the creation of ice crystals and the length of storage can cause some loss.

Texture and Flavor: After being rehydrated, freeze-dried food frequently keeps its original flavour, texture, and shape. Due to its ability to preserve a crispy or crunchy texture, it is prefered for snacks and some fruits. However, thawing frozen food may result in textural changes, including some loss of crispness or hardness. Both freeze-dried and frozen food retain flavour well in general, however freeze-dried foods may taste more intensely concentrated due to the lack of water.
Rehydration and Preparation: Food that has been freeze-dried needs to be rehydrated with water or other liquids before eating because it is already dehydrated. On the other hand, since frozen food keeps its original moisture, it can be cooked or reheated without the need for rehydration.

The decision between freeze-dried and frozen food ultimately comes down to considerations including the product’s intended usage, shelf life requirements, personal taste preferences, and ease of handling and storage.

Are there any specific foods that are better suited for freeze-drying over freezing?

Yes, some goods are better off freeze-drying than freezing, while others might be better off frozen. Here are a few instances:

Foods that freeze-drying is more suitable for:

Fruits: Fruits like berries, apples, and mangoes that have been freeze-dried maintain their distinctive shapes, colours, and flavours. They work well as trail mix ingredients, cereal and dessert toppings, and snacks.

Herbs and Spices: The fragrant qualities of herbs and spices are preserved by freeze-drying, making them perfect for flavouring foods, marinades, or rubs.
Coffee and Tea: Coffee and tea items can be freeze-dried to preserve their original flavours and smells for quick, easy preparation.
Backpacking Meals: For outdoor activities, freeze-dried meals are a popular option since they are portable, lightweight, and quickly rehydrate.

Foods better suited for freezing:

Meat and Poultry: Meat and poultry are frequently preserved by freezing because it preserves their flavour and texture. The freezer is a secure place to keep these things for a long time.
Soups and Stews: Soups and stews, which are liquid-based foods, freeze well and reheat without substantially changing their texture.

Baked Goods:The shelf life of foods like bread, cookies, and cakes can be successfully extended through freezing, albeit there might be a little texture change after thawing.
Vegetables: Vegetables can be frozen to preserve their nutritional content and to make them easily accessible for use in cooking or meal preparation.

While some items may be better preserved using one technique than another, depending on the individual’s needs and tastes, both freeze-drying and freezing have advantages in terms of ease and long-term storage.

How do freeze-dried and frozen foods compare in terms of convenience and ease of preparation?

Foods that are frozen or freeze-dried can be prepared more quickly and conveniently. Here is an evaluation of the two:

Frozen-Dried Foods:

Convenience: Foods that have been frozen and dried are really handy, especially when you’re travelling or out in the elements. They are simple to carry and store because they are small, light, and have a long shelf life.

Preparation: Before eating, most freeze-dried foods need to be rehydrated. This usually entails adding water or another liquid to the freeze-dried product and letting it absorb the moisture for a predetermined amount of time. Depending on the food item, the rehydration process might take anywhere from a few minutes to longer periods of time.
Cooking Requirements: Foods that have been freeze-dried typically don’t require a lot of cooking. They can be used in dishes with little further cooking or heating once they have been rehydrated.

Frozen Foods:

Convenience: In comparison to fresh foods, frozen foods are more convenient because of their easy storage and extended shelf life. They may be purchased already prepared or may be made in advance and kept in the freezer until required.
Preparation: Foods that are frozen typically need to be thawed before cooking. Depending on the meal and desired timescale, thawing can be done in the refrigerator, in cold water, or using a microwave.
Cooking Requirements: Frozen food can be prepared or heated up in a variety of ways after it has thawed, including on the stovetop, in the oven, the microwave, or even an air fryer. Depending on the particular food item and the desired result, several cooking methods and timeframes are used.

Overall, whereas frozen meals need to be thawed before cooking or reheating, freeze-dried foods enable rapid and convenient preparation that mostly involves rehydrating. The decision between the two approaches is influenced by personal preferences, time restraints, and the level of convenience required in a given circumstance.

Can you freeze dry food at home?

It is feasible to freeze dry food at home, but the procedure can be challenging and frequently calls for specialised tools. If you’re interested in freeze-drying food at home, take into account the following important factors:

Freeze Dryer: A freeze drier, a special device made for freeze-drying, is what you’ll need. These devices are pricey and uncommon in typical households. To eliminate moisture from the food, they combine low temperatures and vacuum pressure.

Food Preparation: Before freeze-drying, proper preparation is necessary. In order to maintain the food’s quality and reduce potential microbial development throughout the freeze-drying process, this usually entails cleaning, chopping, and blanching the food.
Freezing: The food is usually frozen after preparation before going into the freeze drier. During the freeze-drying process, freezing aids in maintaining the structure and prevents the growth of ice crystals.
Freeze-Drying Process: Once the food has been frozen, it is put inside the freeze drier, which lowers the temperature and creates a vacuum. The food’s frozen water sublimates, turning instantly from ice to vapour, leaving behind a dehydrated product.

Time and Monitoring: Depending on the product and the equipment used, the freeze-drying process can be time-consuming, frequently lasting from hours to days. To ensure adequate drying and prevent over- or under-drying the food, it’s crucial to carefully watch the process.

Despite the fact that it is technically possible to freeze dry food at home, it is important to note that the procedure can be difficult and requires specialised tools, information, and careful supervision. If you’re interested in freeze-drying food, it could be more practical to look into commercially available freeze-dried goods or find expert freeze-drying services that can manage the process quickly and effectively.