If you are interested in saving food for the future, you should consider freeze drying food for your food storage. This is a great way of preserving foods.
The process of freeze drying is a method used for preserving perishable goods such as food, certain chemicals and even documents, in order to make them light weight, transportable and usable after an extended period of time. Freeze drying as the name suggest consists of freezing the item and dehydrating it by reducing the air pressure surrounding the item.
Then heat is applied in order for the frozen water in the material to sublime directly from the solid phase to the gas phase. This method is used as a preventative method for stopping the re-absorption of moisture in a product which can cause spoilage.
The water and moisture which is dispensed from the product would encourage the development of various microorganisms and enzymes and these are the elements that cause products to spoil. You may decide that you have a few items that you would like to freeze dry and even though it is a relatively expensive process, this article will direct you as to how you can go about it.
There are some tools which are required. First you will need your product, dry ice, a shell freezer, a freeze dry flask, dry ice, liquid nitrogen, a vacuum, a refrigerator, a freeze drying machine if you can acquire one, manifold driers, a condenser plate, and a condenser chamber.
Decide on what kind of product you would like to freeze dry such as fruits etc., and ensure that the product is washed and clean. Once you have selected the item that you intend to use, then you are going to concentrate on the first phase which is pretreatment.
The pretreatment process really depends on the type of product you intend to use. This process may require you to add various components in order to stabilize or improve the product during the pretreatment process.
This may involve solution phase concentration, freeze concentration, formulation to preserve product appearance, and formulation to stabilize reactive products. Unless you have prior knowledge and experience as to how this process can improve this process, it is suggested that this process be left alone and move on the next phase.
The second phase involves freezing. This process starts by placing the product in a flask and then rotating the flask in a bath called a shell freezer.
This is then placed into a mechanical refrigerator that contains dry ice and liquid nitrogen. If the process is being done on a large scale, then it is done through a machine.
Freeze the item until it is cool below its triple point which is the lowest temperature at which the solid and liquid phases of the material can coexist. Bringing it to this point ensures that sublimation occurs instead of melting.
The third process is the primary drying phase. Use the vacuum to lower the pressure of the product to a few millibars (millibars is used as the unit of pressure).
Use the manifold drier to apply a little bit of heat-this is then applied to the material so that the water can sublimate. Be careful not to add too much heat because this can alter the molecular structure of the item.
When the drying phase begins about 95% of the water becomes sublimated. This process can take several days depending on the scale to which you are doing it, in terms of the amount of items you are freeze drying.
Special care needs to be taken when doing this section because if too much heat is applied then the heat could alter the materials molecular structure. A condenser plate and a condenser chamber are used to prevent the water vapor from getting to the vacuum pump because this could degrade the pumps performance.
The final phase of the process is called secondary drying. The aim of this phase is to eliminate the unfrozen water molecules after the ice is removed in the primary drying phase.
Now raise the temperature of the product, higher than in the primary drying phase. After the process is complete, then the vacuum is usually broken with an inert gas such as nitrogen before the material is sealed off.
At the end of the process, the final residual water content in the product should be as low as 1 to 4 percent. Now you are ready to store your products for the future!
Author Resource:-
Terry Daniels is an accomplished expert in family preparedness and has been giving seminars for over 15 years. He recommendsFreeze Dried Foods to be included in your emergency food storage.
Contact Info:
Terry Daniels
TerryDaniels09@gmail.com
http://www.foodinsurance.com/freeze_dried_food/freeze_dried_food.php
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