Guide to different types of materials used to wrap and store food in the freezer.
When freezing food that is going to be stored for several weeks or months in the freezer it is vital that the correct type of packaging is used and that the food is correctly wrapped and stored.
Badly packaged foods can cause freezer burn and lead to loss of nutrients, flavour, colour, texture, taste, moisture and quality. Other similar changes may occur as a result of oxidisation, where air or oxygen comes into contact with the food for various reasons.
Foods should be tightly and carefully wrapped in moisture or vapour-proof containers or materials, ensuring that no air enters the package and that no moisture is allowed to escape or evaporate.
If food items are correctly packaged, provided that they were frozen quickly after purchase and that they were frozen at their optimum freshness, they should emerge from the freezer in perfect condition.
What is freezer burn?
Freezer burn is what happens when food that has been stored in the freezer loses moisture resulting in greyish-white spots or patches on the surface of the food.
These spots are caused by the evaporation of the ice crystals from the surface of the product or by moisture loss. If a product is not properly wrapped, the water molecules can escape to colder parts of the freezer, which is what they prefer, leaving the food item dehydrated and dry.
As water is able to escape, this means that air or oxygen will also be able to enter the packaging and come into contact with the food, creating more deterioration and changes to the product.
Freezer burn is not harmful but it will lead to a deterioration of the product. The food will dry out and become tougher, yet in most cases it will still be edible. Small affected areas can be cut away from the food either before or after it has been defrosted and cooked.
Items with larger areas of freezer burn may need to be thrown away due to the deterioration of the quality.
How is freezer burn prevented?
First and foremost, freezer burn can be prevented by correctly wrapping food intended for freezer storage. This means using correct packaging materials that retain moisture and tightly wrapping the product so that no water molecules are able to escape.
Freezer burn also occurs if a product is stored for too long in the freezer. Therefore, with correct labelling of the product and consumption well within the use-by date, freezer burn will not occur.
Maintaining the temperature of your freezer at 0°F (-18°C) or below also keeps freezer burn at bay, as fluctuating temperatures that rise above 0°F will eventually lead to moisture loss and evaporation.
What type of packaging should I use for storing food in the freezer?
There are a number of options available when it comes to types of packaging for storing food in the freezer. The most popular choices are rigid plastic containers with lids, polythene freezer bags and heavy-duty aluminium foil. However, it all depends on the type of food that you are going to freeze and your own personal preference.
Below are several factors that must be taken into consideration when choosing the type of packaging for your frozen food, followed by some useful information about various kinds of popular freezer packaging:
- Freezer packaging must be moisture and vapour proof.
- It must be able to withstand freezing temperatures without breaking, cracking, warping or shattering.
- It must be airtight.
- Packaging must protect the food from odours and also not affect the taste of the food itself.
- Freezer packaging may be shaped so that the product is easy to store or shaped so that it easily holds awkwardly shaped items.
- Packaging should be easy to label.
- Rigid glass or plastic containers are more suitable for freezing liquids, although headspace must be left to allow for expansion.
- Dry products may be frozen in freezer bags or specific freezer wrapping.
- Freezer packaging should be easy to clean and should not absorb the colour or odour of the food that it contains.
Always check that the packaging that you are buying is for freezer usage. If you are unsure, ask for help or choose a product that does specify that it can be frozen.
Polythene bags are excellent for items that have an irregular shape, as they can be moulded to fit the shape of the food product. All air must be squeezed out of the bag before sealing or closing and this will protect the item from oxidisation and freezer burn.
Freezer bags are more suited for dry products that contain little or no liquid at all, for example fruit, vegetables, pastry or meat.
It is possible to freeze liquids in polythene bags by placing the bag with the liquid inside a rigid container, storing it in the freezer and then removing the rigid container once the liquid is solid.
Polythene bags come in various sizes so that it is easy to find a bag to fit the size of the item you want to freeze.
There are also different methods of sealing the bags. Many bags come with plastic or wire ties or you can purchase special sealing tape for freezer usage, which does not peel off in freezing temperatures. Alternatives are polythene bags that have a zip-lock or those that fold down to seal themselves.
If you have a large freezer and have many items to store, it may be useful to buy different coloured polythene bags and utilise a colour-coded system, so that you know what type of food is inside each bag. For example, you could use red bags for meat and poultry products, green bags for vegetables and blue bags for fruit. Alternatively, the same system could be adopted by using different coloured freezer stickers to label each item.
Using freezer paper is good way to wrap meat and other similar dry, large or bulky items for freezer storage. Make sure that the paper has been designed for freezer storage, as some general types of paper will not hold up under freezer conditions.
Freezer paper is much thicker than normal types of wrap or paper and one side is coated with a layer of plastic. This plastic protects the food from air, moisture and freezer burn plus it helps maintain the quality of the food.
Place the meat or similar item on the side of the paper with the plastic, leaving enough room to fold the paper around the product. Ensure that as much air has been squeezed out and make sure that the edges are sealed and that there are no holes or gaps. Label the packaging on the dull side of the paper with a pen specifically for freezer durability.
Wax paper should not be used to store products in the freezer, as it is not moisture-vapour resistant. Likewise, any type of cardboard or paper container should not be used.
Heavy-duty aluminium foil must be used if intending on freezing products for a number of months. Normal household aluminium foil is not strong enough for long-term freezer storage and should only really be used to protect food items in the refrigerator.
Freezer foil is excellent for wrapping dry products such as meat, poultry, fish and baked goods, as it can easily be moulded around the food item, making it completely airtight and moisture-proof.
Aluminium foil protects against freezer burn, as it is very difficult for any water molecules or moisture to escape. However, care must be taken when freezing certain types of foods, such as acidic fruits, as the acid may react with the metal and produce undesirable changes in the taste and appearance of the fruit. For this reason, it is better to wrap acidic fruits in polythene bags or plastic containers.
Aluminium foil dishes
Aluminium foil dishes come in all sorts of shapes and sizes and are an excellent way of storing prepared and pre-cooked foods in the freezer until a later date.
Pies can be baked in an aluminium pie dish, cooled and then placed in the freezer, thus keeping its shape and making it easy to store.
Similarly, dishes such as lasagne or other oven-based dishes can be prepared in an ovenproof dish and then transferred to a rectangular aluminium dish with a lid for freezer storage.
This type of freezer storage dish may be thrown away after use or can be washed and reused and they are also very economical in price.
Glass jars and dishes
Glass jars and dishes are not the best types of storage container available for freezer usage. Regular glass containers must definitely not be used in the freezer, as the glass will easily break, crack or shatter under freezing temperatures.
Specific jars are available especially for freezer storage purposes.
Freezing liquids in glass jars may be tricky due to the fact that the liquid will expand on freezing. Extra room (about 1-inch) must be left at the top of the jar or dish to allow for this to occur safely.
Foods that have been stored in glass jars should be defrosted first before removing from the jar.
Pyrex glass dishes and containers are ideal for freezer storage, as they are able to withstand very hot and cold temperatures.
For this reason, it is possible to remove a pyrex dish from the freezer and place it directly into a preheated oven without any problems. This is extremely useful if a certain food item such as a pie, quiche
or pasta dish needs to be reheated or cooked through.
Plastic containers are brilliant for storing foods in the freezer. They are available in different shapes and sizes and are easily stacked tidily in the freezer. They are reusable and easy to clean and label.
Plastic containers are suitable for all types of foods, whether they are dry or liquid but they must be able to withstand temperatures below 0°F without warping, opening or cracking. The seal or lid must be airtight and prevent water or air from entering and moisture from escaping, especially if items are going to be stored in the freezer for a long period of time.
Care must be taken when removing the lid from the frozen product, as it may have a tendency to stretch and become out of shape, which will affect its usage at another time.