At this time of the year, many households will be looking in their freezers and making space or defrosting them ready for Christmas fare. In the process, they may well come across foods that just haven’t been used of part packets of food that have been forgotten about. Chest freezers are notorious for this as they are deep and things can get put to the bottom!
In this blog, we are going to look at a common problem that you might well find at home on your food – freezer burn. We may be an industrial and commercial refrigeration installation specialist, but we still have freezers at home, so we think it’s important to mention. Grab a cuppa and have a read!
What is freezer burn?
It sounds like something that happens when you get frostbite! In reality freezer burn is when your food gets covered in ice, on its surface, effectively ‘burning’ it. It is different to when we touch, hold ice which can also burn us (damaging our skin). It might seem strange something cold can cause burns – especially to food, but it is a common problem.
What causes freezer burn to food?
This is where we get a little bit scientific! Freezer burn happens when the food is exposed to air and it loses moisture. That is the easy explanation, but what happens is actually more involved.
Freezer burn normally affects foods that have been frozen a long time, hence the ‘finding it’ at the back/bottom of the freezer and it not looking quite right!
The moisture bit is vitally important in the process of freezer burn. All foods contain water – in varying amounts, these form literally thousands of ice crystals when the product is frozen. These ice crystals start to move to the surface of the food from the inside, reaching the coldest part of the freezer. This process is called sublimation which is a bit like evaporation, however, it doesn’t involve liquids. In sublimation, a substance will change from a solid to a gas.
Have you ever noticed your ice cubes get smaller over time if you don’t use them? This is sublimation working! It also means the longer you keep your foods frozen, the higher the chance of the product getting freezer burn through sublimation – if they are not stored correctly, which we’ll come onto a bit later in the blog.
The loss of water from the food causes it to dehydrate making it dry and tough. Because of the water loss, the food is also prone to having its flavour changed (and colour) due to oxygen changes. This is especially prevalent in foods such as meat and fish.
How can I tell if my food has freezer burn?
Many of you would have seen freezer burn, but not necessarily know what it is. Foods that have been affected with freezer burn often look shrivelled and have a tough appearance. They are often discoloured in areas and covered in ice crystals – giving it a frosty look.
Can all foods get freezer burn?
Any food stored in the freezer could potentially get freezer burn, but because it is caused by dehydration, you’ll find foods with a high amount of water in them can be affected more. Foods such as:
- Use cream.
- Soft fruits.
Baked foods will be dryer and less of a light volume, whereas foods with high starch such as pasta, grains, rice, bread or cake will have a tougher texture.
Foods that have a minimal amount of water content in them are much less likely to be affected, such as nuts and seeds.
Is food with freezer burn safe to eat?
Providing the freezer is set to -18 degrees Celsius (which is zero Fahrenheit, harmful bacteria and pathogens cannot grow, so the food will be safe to eat. Food such as meats need fully defrosting by leaving them in a refrigerator. The foods might not be as nice, maybe tougher with less flavour, but are edible.
How do you prevent freezer burn?
The easiest way to prevent freezer burn is to ensure no air can get to the foodstuffs. Wrapping them properly, making sure tubs are sealed, or any film is in place without air being able to get in is vital. Storing them correctly as directed and for the recommended length of time is also important.
So you can see that although it might not be the best thing for your food, freezer burn is not the end of the food itself. We hope this blog had helped to clear up any concerns you might have about food that has this. As always, if you are very unsure whether food is safe to eat, then please do not take a chance. Using our tips to prevent freezer burn in the first place is much better!