Introduction to Freeze Drying
Freeze drying is an excellent way of extending the shelf-life of food items such as fruits, veggies, ice cream, meat, eggs, and coffee. It is arguably the best drying technique because of its ability to retain food quality in terms of aroma, taste, and nutrients.
Freeze drying, however, is an expensive venture majorly of the high level of efficiency and complexity of freeze drying machines, thereby making it non-available to many. The issue with cost is the reason why people explore other food storage options like drying, salting, freezing, canning, and whatnot. But, what many people don’t know is that they can freeze dry their food items without a machine to conduct the process. Yes, you don’t need to break the bank to acquire a standard freeze dryer and this article will help you find out exactly how in more than one way.
How Do I Freeze Dry My Food Without a Machine?
The concept of freeze drying is to reduce the moisture content of food by freezing and removing the moisture, and the following steps will help achieve just that.
The Freezer method
This is probably the best non-machine freeze drying method, but it takes quite some time to complete. You will need a deep freezer for this method, but your normal freezer will suffice. It is advisable to set your deep freezer to its lowest possible temperature a day before you will be freeze drying; it makes the freeze drying process a lot faster.
This method will work best for high-moisture content foods such as fruits and vegetables like strawberries, apples, guavas, oranges, carrots, and raspberries. You can also employ it in storing sea food like fish, shrimps, and other food items like beef, cheese, pasta, chicken, herbs, and even desserts. It is also advisable to wash your food items before freeze drying them, it saves you the hassle of washing them again after prying them from the tray.
Cut large fruits and vegetables such as apples and potatoes into small pieces and arrange them spaciously on a cookie sheet, air drying rack, or cooling rack. You can leave smaller fruits like the berries just like they are and arrange them on the selected tray. Endeavor to also cook your meat and cut them into smaller pieces before placing them on the tray for freeze drying. Make sure you space the food items so they don’t come in contact.
After arranging the food items, place the tray on a flat surface in the deep freezer (or freezer) and wait. Ideally, 10 days should be enough for total freeze drying, but sometimes, it isn’t. Confirm freeze drying by bringing out one of the cut food items for a few hours under room temperature and keenly observe any change in color. If the item displays dark coloration, assume that the freeze drying is not fully done yet. Discard the test sample, and leave the rest in the deep freezer for a few more days.
After confirming total freeze drying, store the rest of the food items in a ziplock bag under 75°C. Make sure that the ziplock bag is free from direct sunlight, moisture or air. Push out the air content from the ziplock bag as much as you can. Freeze drying extends the shelf-life of food items by as much as 15 times, so your freeze dried foods can stay in good quality for months and even years. Although this process can take weeks to complete, it is well worth the wait.
Dry Ice Freeze Drying
This is a much faster method and is also quite effective. Just like the first method, cut large food items into smaller pieces and don’t forget to cook the meat and pasta (you don’t have to slice the pasta).
After washing and cutting the food items, transfer them into a ziplock bag. Ensure that you put only the same type of food item into the same bag; don’t mix meat with fruits, or cheese and pasta. Don’t forget to push out as much air as you can from the ziplock bag.
Next, you will need a large container about twice the size of the bagged food items, but it has to be a container you don’t really much use of. You will find out why later on. You can use one container for more than one bag to manage space
The idea is to sandwich the food item between two chunks of dry ice. Pour a chunk of dry ice in the empty container, place the bagged food on the ice, and pour some more ice on the food. The amount of ice should be the same as the amount of food you want to freeze dry, so if you want to freeze dry about 4 grams of food, you will need about 4 grams of dry ice to make it even. You will need insulating gloves for this part to protect your hands from the freezing sensation.
Depending on the size of the container, you can store more than one food item. All you have to do is arrange one atop the other without them coming in contact (both sides of each bag of food should be in contact with dry ice).
DO NOT SEAL OR CLOSE THE LID OF THE CONTAINER.Sealing the container lid will lead to an explosion due to the accumulation of gas from the ice in the container, so to prevent that, loosely close the container lid or puncture holes in it. Either way, NEVER SEAL THE LID.
Place the container inside a deep freezer for at least 24 hours before checking for total freeze drying. Freeze drying is complete once all the ice in the container is gone. If after there’s still some ice after 24 hours, place the container back in the freezer and place the lid just as it was, and wait for another 5 hours before checking again.
After confirming total freeze drying, bring out your freeze dried foods and store them under room temperature. To ensure that your food items retain their quality, push out as much air as you can from the bags, and keep away from direct sunlight.
Now you know how to freeze dry food from home without a machine. Put the knowledge into good use.