Do's and Don'ts of Freezing Foods
One of the major forms of food preservation is freezing, and an important part of frozen food storage is the container the food is packed in.
There are several different types of packaging materials that work well in freezers. They include rigid containers, flexible bags, collapsible cover boxes and freezer wrap. These materials help prevent freezer burn and the breakdown of textures in frozen foods; they also prevent color and flavor changes.
Rigid containers can hold most foods. The containers are re-usable and are easy to stack. They are helpful for storing foods that contain liquids.
The most common and popular rigid container is one made of moisture-vapor-resistant plastic with a snap on lid. With proper care, these plastic containers can be used for years.
Wash lids in warm, never hot, water. Be careful as you remove the lid from the container because the lid may stretch and not fit securely. Then the container will not be airtight. It is best to let cold water run over the lid before removing. If the lid stretches, use freezer tape to seal it securely on the container. Use plastic wrap and aluminum foil in place of freezer tape. Stretch the wrap or foil on top of the container under the lid.
Glass jars can also be used to store frozen foods, but they should not be used to store liquids. If you use glass jars, be sure to choose the wide-mouth, dual-purpose jars that are for freezing and canning. These jars are specially made to withstand freezing and boiling temperatures.
The wide mouth of the jar allows easy removal of partially thawed foods and gives room for expansion during freezing. Leave at least 1 inch of headspace (the unfilled space above food or liquids in jars or freezer containers) for expansion. Also, new lids should be used each time and rinsed in cold tap water before applying to the mouth of the jar.
Standard canning jars with shoulders can be used for frozen food storage, but there is a danger of breakage if the jar is filled above the shoulder. Thaw food before removing from these jars. Extra care should be taken when thawing foods stored in glass.
Another popular method of storing frozen foods is using bags made of moisture-vapor-resistant polyethylene. They work well for dry food products and also can be used for liquid packs.
When sealing a freezer bag, leave no air in the bag with the food. After removing all the air, twist the top of the bag to form a spiral and fold it over like a gooseneck. Wrap the gooseneck several times about a half-inch from the food with some sort of a closure material. If a covered-wire closure is used, be sure to wrap the ends so they won’t puncture the bag. The bag should be loose to allow food to expand during freezing.
Collapsible cover boxes are often used with freezer bags. They protect the bag from puncture and make it easier to stack the packages. With good care, cover boxes can be reused for several years, but it is better to use new bags each time.
A good material for wrapping meats and other large and irregularly shaped foods is freezer wrap. Common types of freezer wrap are freezer paper, freezer cellophane and freezer aluminum foil (0.0015 thickness).
If freezing paper is used, only the paper made especially for freezing should be used. Do not confuse ordinary wrapping cellophane or butcher paper with specially developed grades recommended for freezing.
Household wax paper, plastic wrap and heavy-duty aluminum foil are not recommended for wrapping foods to be frozen. Extra-heavy-duty aluminum foil can be used for freezer storage for up to eight weeks. Wrap meats from the supermarket in suitable freezing wrap before freezing because the supermarket wrap is porous and may contain small holes.
Freezer tape helps seal packages of food to be frozen and makes the packages more airtight. However, such tape must hold a tight seal at 0 F or below.
Several materials are not good for long-term storage of frozen food. Foods stored in these materials for long periods of time may develop freezer burn and absorb undesirable odors. The materials include wax paper, paper cartons, cottage cheese cartons, cardboard ice cream or milk cartons, any rigid container that may crack and any container that has a poorly fitting lid.
Good materials for freezing should be airtight when properly sealed, be moisture-vapor-resistant, be durable and able to withstand cold temperatures, easy to clean, odorless and tasteless. They should not absorb oil, grease or water. They should also be easy to handle, seal, label, stack and take as little room as possible.
Source:Evelyn Crayton, Extension Foods and Nutrition Specialist, Alabama Cooperative Extension System, (334) 844-2224
Prepared by Jana Huggins, Agricultural Journalism Intern