freeze dry

How to properly freeze drying for removing moisture from food

Freeze drying removes moisture from food through sublimation, which turns water molecules into vapor. Freeze-drying food affects the structure more than other preservation methods, such as pickling or freezing, but the nutritional value and flavor remain intact. Because freeze-dried foods are so lightweight, they’re great for taking on hikes or storing in an emergency kit. Read on to learn more about freeze drying and processing using different freeze drying methods.

Preparations for freeze drying food

Select foods to freeze dry.

Foods that contain a large amount of water are best suited. Their structure remains intact after the process. These foods keep especially well: Fruits such as apples, bananas, berries, persimmons and pears. Vegetables like potatoes, peppers, carrots, sweet potatoes and parsnips. Once you’re comfortable with the process, try freeze-drying chicken breasts, cheese, and even whole meals like spaghetti with meat sauce. Any food that contains moisture can be preserved by freeze drying.

Choose foods that are as fresh as possible.

Food that is freeze-dried at the peak of its freshness or ripeness will definitely taste good when reconstituted. Fruits and vegetables should be freeze dried when they are in season and fully ripe. Meat should be freeze-dried immediately after cooking and preparation. Full meals should be freeze-dried once prepared and cooled. Don’t freeze-dry them after storing them in the fridge for several days, or they’ll taste like leftovers once reconstituted.

Avoid freeze-drying foods that don’t taste good after reconstitution.

Berries and apples don’t need to be reconstituted – the freeze-dried version tastes good as is. Freeze-dried meat or spaghetti, on the other hand, must be reconstituted with liquid in order to become edible. Do not freeze-dry foods that cannot be freeze-dried. Bread is not a good choice for freeze drying because its texture depends so much on freshness. Cakes, cookies, and other foods containing yeast are not good candidates for freeze drying.

Process the foods for freeze drying.

Prepare foods for preservation as follows: If applicable, wash and dry foods thoroughly. Cut the food into small pieces. Cut *apples, peppers, potatoes and other fruits and vegetables into small pieces so that moisture can escape easily.

Freeze dry food in the freezer

Place the food on a plate or platter.

Spread them out so they don’t clump together.

Place the plate in the freezer.

If possible, make sure the freezer doesn’t contain any other items. If possible, do not open the freezer while it is freezing. This slows down the freezing process and causes ice crystals to form on the food. If you have a freezer, use that. Food should be frozen at the lowest possible temperature.

Leave the foods in the freezer until they are freeze-dried.

Over the course of a week, sublimation takes place and all moisture is removed from the food. Check if the food is completely freeze-dried by removing a piece and letting it thaw. If it turns black, it’s not freeze-dried yet.

Save the groceries.

When the food is fully freeze-dried, place it in freezer bags. Squeeze out the air, seal the bags, and store in either the freezer, pantry, or your emergency kit.

Freeze dry food with dry ice

Put the food in freezer bags.

Lay the bags flat so the food doesn’t pile up in one corner. l Squeeze out the air before sealing the bag. Make sure the bags are sealed airtight.

Place the freezer bags in a large cooler.

Cover the food with dry ice. wear gloves and long sleeves when touching the ice. If you have a lot of bags of groceries, alternate layers of dry ice and groceries until the cooler is full.

Place the cool box in the freezer.

Cover the box with a lid after 6 hours. After 24, check if there is still ice in the box. When there is none left, the food is ready for storage.

Take the bags of groceries out of the cooler.

Either store them in the freezer, in the pantry, or in your emergency kit.

Freeze drying food with a vacuum chamber

Put the food on a plate or platter.

Spread them out so the pieces don’t clump together.

Place the sheet in the freezer and freeze until solid.

If possible, there should be no other items in the freezer. Don’t open the freezer often while the food is freezing. This slows down the freezing process and causes ice crystals to form on the food. If you have a freezer, use that. Food should be frozen at the lowest possible temperature.

Place the frozen food in the vacuum chamber at approx.

120 mtorr. Set the temperature to 10ºC. The sublimation process should be completed within a week depending on the parameters set. After a reasonable time has elapsed, examine one of the slices to verify that freeze drying is complete.

Place the food in airtight containers for storage.

Restoration of freeze-dried foods

Take the food out of the pack.

Place them in a bowl or saucepan.

Boil a few cups of water on the stove.

When the water boils, remove it from the flame.

Pour a little boiling water over the freeze-dried food.

It will expand and absorb the liquid. If it seems to need more water, give a little more on top. Repeat this until the foods are fully restored.

Tips

The purpose of storing freeze-dried food is to reduce the activity of water and the liquid content so that microbial activity is blocked. The addition of a pack of silicone gel reduces the possibility of condensation and moisture inside the container.

Warnings

Store the food in proper containers to prevent it from spoiling. Handle dry ice with care. It burns your skin when you touch it.

About the Author

Edison Greenwood

Edison Greenwood is a Outreach Editor for Freevoucherhub. He has worked for years in SEO and Digital Marketing and has a long history in e-commerce industry. When not writing he teaches yoga, editing videos, and DIY furnitures.