Whether you are stockpiling food for a doomsday event or simply want healthy backpacking meals, freeze drying food is a great way of preservation. This is because freeze-dried foods are lightweight, can last decades, are easy to rehydrate, and actually taste nice. You can now make this at home, with your very own home freeze drying machine.
This is good, because freeze dried foods from shops is very expensive. A home freeze drying machine isn’t cheap, but in the long run, it may work out cheaper for you.
There are a few options for your home freeze drying machine. But, there are a few things you need to know (including whether it’s worth the cost!), before buying one.
What is Freeze Drying?
You know when you are podium dancing in a nightclub and the smoke machine switches on? Well, this is the result of dry ice turning directly in to a gas. This process is called sublimation.
A home freeze dryer uses sublimation to remove water from food. The scientific name for this food preservation method is lyophilisation (every day is a school day).
Freeze drying isn’t a new thing, it has been used for thousands of years. But, it was used in world war 2 to transport blood and organs. Then later, it was used for long storage of food.
How Does a Home Freeze Dryer Work?
A home freeze drying machine uses quite a simple process that takes around 20 hours.
- You put food into the freeze dryer chamber.
- The machine flash freezes the food so the water inside it turns to ice. Harvest Right units go to -30°F or colder.
- A pump removes air from the chamber, creating a vacuum.
- Because pressure is low inside the vacuum, the ice turns into vapor.
- A low-temperature condenser pulls the vapor out of the chamber
When the home freeze drying machine has finished, you will have food which is free of water and is chemically-stable. If you store it properly, it can last up to 25 years. You can see why this process is popular with doomsday preppers.
A good freeze drying machine will do everything automatically. They have sensors that monitor humidity which will automatically turn off once the water vapour has gone.
Benefits of Using a Home Freeze Drying Machine
1. Keep the Nutrients in your Food
Freeze drying preserves nutrients in food.
- Freeze dried foods retain 97% of nutrients
- Dehydrated foods retain 60% of nutrients
- Canned foods retain 40% of nutrients
Freeze drying is so great for keeping nutrients in food because no heat is used. Vitamins and antioxidants are very sensitive to heat. Lots of vitamins are also water-soluble. This means they can be lost into the liquid used in canning.
2. Taste and Texture
Some freeze dried foods taste even better than fresh ones. Examples are, berries and some veggies. However, not all freeze dried foods taste nice, especially when you rehydrate them. Some freeze dried meals, such as lasagna are not particularly nice. This is due to the texture, as it goes a bit odd. But, compared to canned or dehydrated foods, the texture is generally a lot less mushy.
3. Storage Life
Some freeze dried foods can last over 25 years, assuming that you keep them away from light and moisture.
Canned foods can also last this long. But, home canning usually involves glass jars. These don’t fare well in an earthquake or a alien attack.
Because all the moisture is removed from the food, it is very light. This makes it great for hiking, camping or running from zombies.
Can I Freeze Dry Food Without a Home Freeze Drying Machine?
Yes you can. However, you do this by putting the food in the freezer. It is a more involved process and there are a few problems.
Primarily, it takes a very long time to do. In a normal freezer, it will probably take months to completely freeze dry food. This isn’t a very effective way, nor is it very practical, unless you have a few spare freezers. Also, if you are prepping for an emergency and your food hasn’t been preserved in time, it kind of defeats the object.
The second problem is that, only the surface of food will freeze-dry. Your freezer will only allow sublimation on the surface of the food. That means it impossible to freeze dry thicker foods. Herbs and a few veggies, may be OK, but you won’t be able to freeze dry anything bigger properly.
The third problem, is that bacteria isn’t killed. Freeze drying (whether in your freezer or with a home freeze drying machine will not kill bacteria. However, a home freeze drying machine machine removes all water preventing bacteria from growing. You will never be sure that all moisture was removed from freezer-burned meat though, so bacteria could keep growing while it is storage.
Realistically, if you want to freeze dry food. You need to buy a home freeze drying machine.
You may also want to look in to a food dehydrator as an alternative.
What Food Can You Put in a Home Freeze Drying Machine?
You can put pretty much anything in a home freeze drying machine. However, you get the best results from foods with high water content.
- Tree fruits like apples and plums
- Fruits like tomatoes, peppers, zucchini, and pumpkin (yes, they are actually fruits!)
- Root veggies like carrots and potatoes
- Most cooked or blanched veggies
- Cooked pasta
- Cooked beans and legumes
- Condiments which don’t contain too much sugar
- Entire meals, soups, or sides (so long as they don’t contain too much oil, fat, or sugar)
Foods That Don't Freeze Dry Well or at all
- Greens like spinach, kale, and lettuce go wilted and soggy.
- Raw vegetables, go tough, so you need to cook or blanch them first
- Sweet fruits like peaches take a very long time because their sugar content is so high
- Big pieces of food will take a very long time to freeze dry and to rehydrate. Also, the texture will be weird.
- Fruits with tough skins, as the skin makes it difficult for moisture to be extracted. It will work if you cut the fruits in half before you put them in your home freeze drying machine
- Very watery fruits like watermelon don’t work well, because there isn’t much left after the freeze drying process. In fact, you are left with a powder.
- High fat foods don’t work, as the fat just melts and makes a horrible mess in your home freeze drying machine
- Foods with a high sugar content will take a long time to process
The Disadvantages of a Home Freeze Drying Machine
1. Home Freezings Drying Machines Are Massive!
The smallest dryers are about the size of a mini fridge. They are also VERY heavy.
You will want to keep it somewhere out of earshot like your basement or garage when running. They are as loud as a vacuum cleaner.
3. They Need Maintenance
You will need perform regular maintenance on your home freeze drying machine:
- Change the oil after every 5-7 batches
- Do a power flush after every 10-12 batches
- Clean the interior of the machine regularly
4. Oil Spraying
One common problem is that oil can spray. This is because the oil level in the pump is finicky and hard to get perfect.
Once the machine is turned on, the oil level will increase a bit because of motion. The hot oil can then start to mist or splatter all over the place. This also happens if the pump malfunctions and can’t create a vacuum.
Compared to other home food preservation methods, freeze drying costs a lot of money.
Is a Home Freeze Drying Machine Worth The Money?
The biggest downside to home freeze drying machines is the cost. But packages of freeze-dried foods are also very expensive.
It would be worth buying a home freeze drying machine if:
- If you use it more than once per week
- You grow your own food or buy fresh foods in bulk at a discount
- If you are freeze drying meals, since these tend to be much more expensive per weight than single ingredients.
You probably won’t see the monetary advantage for about a year. But, any longer that that, you will be laughing. If you were to split the cost with a neighbour or another family, it would be more cost effective.
The best home drying machines are made by Harvest Right. Here are some examples you need to check out. They vary in price, but none are cheap.
What are your thoughts on freeze drying? Let us know in the comments section below.