Freezing Fundamentals

Freezing is a great way to make food last longer and avoid spoilage. This doesn’t mean food won’t go off if you keep it in the freezer forever, and once defrosted it will need to be used up quickly.

Lots of different types of foods can be frozen, whether it’s the extra loaf of bread you bought or the cooked pasta you want to use for lunch later in the week.

For some foods the process of freezing is a little more complicated than just popping it in the freezer, so we’ve got a few tips on the extra steps you need to know and a list of some foods you might not have known you could freeze.


Many vegetables, such as hardy greens (broccoli, sprouts and green beans), root veggies (carrots, parsnips, cauliflower, squashes and sweet potatoes) are best blanched before freezing. Blanching is a technique that involves exposing foods to boiling water or steam for a short period of time and then rapidly cooling them to prevent cooking (this is called refreshing). It stops enzymes in the food from activating, kills micro-organisms and improves the colour, texture and nutrients of frozen foods.

Water content

Water expands by almost 10% when it turns to ice. It’s this phenomenon that can cause the forgotten bottle of beer to crack if left in the freezer but it also affects foods when they are frozen. Fruit and vegetables are largely made up of water. As it freezes and expands, the ice crystals can burst the plant cell walls. When the food is defrosted, it’s texture can be ‘mushier’ than before it was frozen. This makes a difference for food that would be eaten raw but for food that will be cooked, it makes little difference. For example, defrosted lettuce and cucumber wouldn’t make for a good salad but frozen spinach is still great in a curry and frozen courgette is perfect for soup.

Only freeze once:

It is only safe to freeze foods once. For prepared foods, check the packaging before freezing. Sometimes these products have been already frozen in the supply chain so cannot be frozen again.

Best to avoid:

When food is defrosting, it is possible for bacteria to reactivate and start to multiply. This is why it’s best to defrost foods in the fridge and why some ‘high-risk foods’ are best kept out of the freezer in the first place. Things like fully-cooked rice, fried foods, cooked eggs or foods with high mayo or raw egg content are safer not to freeze.

Time, temperature, humidity and light are the main factors to consider when storing food.

Importantly, correct storage also plays a vital role in maintaining the nutritional value of food and ensures it will be safe for consumption.

Here are some examples of food you can freeze that you may not already know about:

Sauces & Stocks – Just put them in ice cube containers.

Grapes – Grapes make a great icy treat!

Peppers & Onions – Dice them up and pop them in freezer bags.

Flour – Store flour in the freezer to make it last longer.

Cheese – In blocks or grated, cheese can be frozen.

Eggs (no shells) – Freeze in bun trays, thaw and use as normal!

Cooked Pasta – Cook a batch, freeze in a bag, save time cooking!

Nuts – Keep nuts for longer in the freezer.