FAQs

  • Preserving food and other perishable items has been an ongoing challenge for humanity. But with the advent of technology, we now have advanced methods to extend the shelf life of various products. One such technology that has revolutionized preservation is freeze drying. 

    Freeze drying, also known as lyophilization, is a process that involves removing the moisture from a product while preserving its structure and nutrients. It is commonly used to preserve food, pharmaceuticals, biological samples, and other perishable items. Freeze drying offers a longer shelf life compared to other preservation methods, while retaining the product's original flavor, texture, and nutritional value.

    How Does a Freeze Dryer Work?

    Freeze dryers are sophisticated machines that utilize the principles of sublimation to remove water from a product. The freeze-drying process typically consists of three main stages: freezing, primary drying, and secondary drying.

    1. Freezing: The first step in freeze drying is to freeze the product. By lowering the temperature, typically to around -40°C (-40°F) or below, the water in the product solidifies into ice crystals. This freezing process helps preserve the structure and prevents damage to the product's cells during drying.


    2. Primary Drying: Once the product is frozen, the freeze dryer creates a vacuum. This vacuum allows the frozen water to sublimate directly from solid ice to vapor without passing through the liquid phase. The pressure difference between the vacuum chamber and the frozen product causes the ice crystals to vaporize. Heat is then applied to the product, usually through heated shelves or radiant heat, which aids in the sublimation process.


    3. Secondary Drying:  After the primary drying stage, there may still be residual moisture remaining in the product. To remove this moisture, the temperature of the freeze dryer is increased slightly. This additional heat helps evaporate the remaining water molecules, ensuring the product is completely dry. However, it is essential to maintain a controlled environment to prevent any adverse effects on the product's quality.

    -Bluealpinefreezedryers.com

  • Freeze-dried food can maintain its quality and freshness for 25+ years when stored in proper conditions,

  • Yes! Watermelon can be freeze dried!

    Freeze-drying watermelon is a healthy snack that retains its nutrients and vitamins for months or years. It can be eaten on its own, blended into smoothies, or used in baby food. Freeze-dried watermelon can also be used in cooking and baking.

  • Dehydrating and freeze drying are both effective methods for preserving food by removing moisture, but they differ in several ways: 

    • Nutrient retention: Freeze-dried foods retain more nutrients than dehydrated foods. Freeze-dried foods retain about 97% of their nutrients, while dehydrated foods retain only about 60-75%. 

    • Shelf life: Freeze-dried foods have a longer shelf life than dehydrated foods. Freeze-dried foods can last up to 20-25 years, while dehydrated foods last about 5-15 years. 

    • Texture: Freeze-dried foods are usually crunchy, while dehydrated foods can be chewy or crispy. 

    • Size: Dehydrated foods can shrink more than freeze-dried foods. 

    • Cost: Dehydration is more cost-effective and energy-efficient than freeze drying. 

    • Equipment: Freeze drying requires specialized equipment. 

    • Process: Dehydration is one of the oldest food preservation methods, used by prehistoric people to sun-dry seeds. Freeze drying uses a process called sublimation, which transforms ice into vapor. 

    • Taste: Freeze-dried foods generally taste better than dehydrated foods. 

    • Rehydration: Freeze-dried foods rehydrate faster than dehydrated foods. 

    • Variety: A wider range of foods can be freeze-dried than dehydrated.