FAQs
General Questions
Q: What is freeze drying?
A: Freeze drying, also known as lyophilisation, is a process that removes moisture from food or other items by freezing them and then using a vacuum to turn the ice directly into vapour, skipping the liquid phase. This preserves the structure, flavour, and nutrients of the product.
Q: What can I freeze dry?
A: You can freeze dry a variety of foods, including fruits, vegetables, meats, dairy products, complete meals, and even desserts. It’s also used for non-food items like flowers, pet food, or pharmaceutical products.
Q: How long does freeze drying take?
A: The freeze-drying process typically takes between 20 to 40 hours, depending on the type and amount of food being processed.
Q: What are the benefits of freeze drying food?
A: Freeze drying preserves up to 97% of nutrients, extends shelf life for up to 25 years (when properly stored), and retains the original taste, texture, and appearance of food.
Q: Is freeze-dried food the same as dehydrated food?
A: No. Freeze drying removes about 98-99% of moisture, while dehydration removes around 90-95%. Freeze-dried food retains more nutrients, flavour, and texture compared to dehydrated food.
Using a Freeze Dryer
Q: How does a freeze dryer work?
A: A freeze dryer works in three main steps:
Freezing the food to very low temperatures (-40°C or colder).
Creating a vacuum to lower the air pressure.
Applying controlled heat to sublimate the ice into vapour, leaving the food dry.
Q: Are freeze dryers easy to use?
A: Yes, modern freeze dryers are user-friendly. Simply load the trays, start the machine, and let it run. Many machines have automatic settings for different types of food.
Q: How much food can I freeze dry at once?
A: The capacity depends on the size of the freeze dryer. Small home models typically handle 2-3kg per batch, while larger models can handle up to 8-10kg.
Q: Do freeze dryers require special maintenance?
A: Yes, routine maintenance is needed, such as cleaning the machine, draining the vacuum pump oil (if applicable), and checking for proper seals.
Storage and Shelf Life
Q: How do I store freeze-dried food?
A: Store freeze-dried food in airtight containers, such as Mylar bags with oxygen absorbers or vacuum-sealed jars, to prevent moisture and oxygen exposure.
Q: How long does freeze-dried food last?
A: When stored properly, freeze-dried food can last up to 25 years, making it ideal for emergency preparedness or long-term storage.
Q: Can I rehydrate freeze-dried food?
A: Yes, simply add water to rehydrate the food. The amount of water needed depends on the food type, but it generally rehydrates quickly and returns to its original texture.
