Guide to the preparation of food to be stored in the freezer.

preparing food freezer
Whether you are freezing raw meat, fresh vegetables or a homemade Shepherd's pie, there are guidelines that need to be followed in order to ensure that what you put into the freezer comes out in the best condition possible.

In another section of our storage guide, we give in-depth information on how to best freeze certain types of foods, whilst on this page we offer a brief overview of how to store and organize food intended for long-term freezer storage.

Correct packaging

Some types of packaging are best suited to certain types of food. For example, a joint of meat should be wrapped in heavy-duty polythene and then placed in a heavy-duty polythene bag and sealed, whereas a pasta sauce could be packaged in a number of ways, such as in an airtight plastic container, glass jar or a polythene bag.

The first thing to do when you have a product to freeze is to choose the most suitable type of packaging according to that type of food.

This means that you should choose a container or wrap most similar to the size and shape of the food item. A few frozen vegetables should not be stored in a huge container, as a polythene bag will suffice. It is important to know how to package and store different types of foods and also different foods within each food type.

For example, not all fruits should be frozen in the same way, therefore if you are unsure, you should check each item separately, so that you are not disappointed once you have defrosted that product and found out that it has been ruined.

Another point to consider is how the food item is going to be cooked or reheated once it has been defrosted, as this could affect which type of material or container is used for freezer storage. Unbaked pies can be frozen in ovenproof dishes, so that they can be placed straight from the freezer into the oven to bake without having to hunt around for suitable dishes and transfer the pie from one to another.

Likewise, any foods that will be reheated or defrosted in the microwave should be wrapped or stored in microwave safe materials.

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

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.

Freezer paper

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.

Aluminium foil

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

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.

Preparation before storing

Once you have found a suitable storage container or materials for the items that you are going to freeze, you must also check whether there are any specific preparation guidelines to follow before freezing.

For example, vegetables are best when blanched (immersed in boiling water) first, as this halts the action of the enzymes within the vegetables and meat will possibly need to be jointed and have any excess fat removed for the best results.

Some types of foods can be frozen as they are whilst others may need liquid added or certain ingredients removed until after defrosting.

It is really important that only good-quality fresh food is frozen, as this will ensure perfect results later on.

Cool food before freezing

All food items must be cooled completely before packing and storing in the freezer. This is imperative, as if warm or hot food is placed into the freezer it can cause the temperature of the freezer to fluctuate and rise. This may have several effects on food that is already being stored in the freezer and also on the items that you are going to freeze.

If the temperature in the freezer rises above 0°F (-18°C), foods that are already frozen could defrost slightly and then refreeze. This will lead to a deterioration of the food item, as small ice crystals become larger on refreezing, thus damaging the cell walls of the food as they expand.

Once a product has been frozen it should stay completely frozen and not undergo changes in its storage conditions that will affect its quality after defrosting. Fluctuating temperatures will also lead to freezer burn, which could potentially destroy a food item resulting in having to discard it uncooked and uneaten.

Secondly, the cooler the item ready to freeze, the quicker it will freeze. This is important, as foods that freeze rapidly will not be structurally damaged by the freezing process.

The quicker an item freezes in the freezer, the better the quality of that item when it comes to defrosting, as much of the moisture content, vitamins, texture and flavour are retained.

When cooling foods intended for freezer storage, this should be done as quickly and as safely as possible. Do not leave any food, especially foods containing poultry, seafood, eggs, fish or meat, out to cool at room temperature, as this could cause bacteria to multiply, food contamination and the rapid deterioration of the dish.

Such items should be cooled quickly in the refrigerator or by placing the dish or original cooking pan in a sink or bowl full of ice cold water, which should be changed every so often to ensure the quickest cooling time possible.

Freeze small portions

Items that you are going to store in the freezer should be frozen in small or individual portions. This is so that they freeze quicker, thus ensuring a better quality product on defrosting and so defrosting for a certain number of people is made easier.

If there are only two of you at home, it does not make sense to defrost an item of food intended for six people and smaller items will also defrost quicker, which may help if time is lacking.

Freezing liquids

Although most foods require excess air to be removed from the packaging before freezing, this is slightly different where freezing liquids is concerned.

A slight gap or space should be left at the top of the container, as liquids will need the extra room, which will be filled once the liquid expands on freezing.

The recommended space to leave is 1-inch for 1 pint of liquid and 2 inches for a litre.

Label all freezer packages

Labelling each package that goes into the freezer is particularly important if you have a large freezer that is full of frozen items.

It is easy to forget what is inside each package and the date on which it was frozen. This means that you could end up defrosting something that you didn't want to defrost, as you mistook it for another item or that food stays in the freezer for too long and cannot be used, as the recommended storage time has passed.

Label each food package by using special low temperature freezer stickers that can withstand freezing temperatures without peeling off and write on the stickers with pencil, wax crayon, biro or marker pens to ensure that the ink does not run or wash off.

Label the food packages with as much information as possible for example, the date, the contents, whether the item is sliced, grated or whole, number of servings or portions and use-by date. This is important so that you know exactly when you should use the contents by.

As well as writing specific freezer storage details on the labels, it is also a good idea to use a colour-coded system so that knowing what is inside each package is easier when you are rummaging around in the freezer. Using red labels for meat, white for poultry, blue for fish, green for vegetables and yellow for fruit is a good idea.

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