Maintaining a normal freezer temperature is about more than what's good for your appliance or energy efficiency. It's about the healthfulness and longevity of your food. It's also about preventing waste. We live in a culture that wastes enough food to feed every hungry person on the planet, and believe it or not -- freezer temperature has a lot to do with it.
But there's more to it than determining a number in Fahrenheit or Celcius. You have to first understand what you're trying to preserve and what you are trying to prevent. Only then can you truly appreciate not only what is the normal temp, but why that's important.
Human beings have been finding creative ways to freeze food for thousands of years. Leaders like Alexander the Great have considered refrigeration an extremely important issue. Washington had the foresight to use it wisely, harvesting enough ice from the Potomac to last six months after the spring thaw. Others, like Napoleon, were unwitting players in the invention of something wonderful. An ice machine, delivered to him in exile, is one of the first examples of science creating ice artificially.
Freezing technology is important. Indeed the survival of any civilization depends, in part, on its ability to store food. But you have to do it at the right temperature.
A Brief History of Refrigeration
Refrigerating and freezing food has been around for thousands of years. The ancient Mesopotamians dug pits, lined them with straw and sand and filled them with mountain snow. That kept meats from spoiling for two to three weeks. In the 1600s, ice houses began springing up across Europe.
An ice house is a building with a thatched roof that sits partially underground. Insulated with sawdust packed with snow, the ice houses of Europe used mountain lake ice to keep food from spoiling and to offer ice chips for drinks and treats.
The ice house reigned supreme until the invention of the icebox. Just like it sounds, the icebox was a box or cabinet that held a big chunk of ice that kept an insulated compartment cold. That was how people froze food until the first production mechanical freezer in the 1920s. And for nearly 100 years, the freezer that we know today has helped keep our food safe and protected.
What's a Normal Freezer Temperature?
Your freezer, whether it's a fridge/freezer combo, chest style, or standup, should maintain a temperature of 0 degrees Fahrenheit or colder (-18 degrees Celsius). While it is true that food freezes at 32 degrees Fahrenheit, for safety and long-term storage, barely frozen isn't good enough. 0 degrees isn't just recommended; in food service, it's a requirement. Most commercial kitchens are so concerned with the consistency of their frozen stock that they have an alarm that sounds if their freezers go even one degree above zero.
Many people don't make as much use of their freezers as they could, because they don't believe that frozen food can taste as good as fresh. Those people miss out on great prices on meats and other products sold in bulk. With a little bit of searching and reading, you can save money, shop less often and stop throwing away food altogether. But you have to keep the food frozen, and frozen well.
Why Maintaining a Normal Freezer Temperature is Important for Your Health
It is a myth that freezing kills all bacteria and other nastiness. It doesn't. Some bacteria, like that which grows on the surface of a piece of meat, will die in the freezer. Others, however, continue to live on.
What it freezing does do, however, is to stop existing bacteria from multiplying. That piece of meat you left in the fridge until the "freeze by" date has already started to grow bacteria. When you get it to freezing, the growth stops. At the normal freezer temperature of 0 degrees, bacteria lie dormant.
When you defrost, the bacteria will come to life again. The difference is, the protein hasn't been sitting in your fridge for days, weeks, or months spoiling. It was put into a cryo-chamber until you could find the perfect pesto. Now that it's out, you'll have to treat it like the meat that was about to expire when you froze it.
Freezing stops the growth of salmonella and the bacteria that cause botulism, both of which can make a person very, very sick. As for the bacteria that cause food spoilage -- discoloration, leakage and foul odor -- freezing will stop those, too. Food spoilage bacteria are far less likely to harm you. However, nobody enjoys eating spoiled food.
Why Maintaining a Normal Freezer Temperature is Important for Your Food
The ability to freeze food changed everything. Science discovered that food stored at 0 degrees was basically held in a state of limbo. Different foods react to freezing in different ways, but most foods can be essentially suspended in time.
That does not mean, however, that you can just toss your problems in the freezer and they'll go away. Meats purchased fresh from the case, for example, are wrapped in plastic and sitting on a styrofoam meat tray. If you take that package and put it straight in the freezer, you're solving your storage issues at the cost of the quality of your food.
Taking the time to see how long your item can be stored in the freezer and wrapping it properly will prevent avoid freezer burn and loss of flavor.
Avoiding freezer burn
"Freezer burn" occurs when a food product is directly exposed to the freezing cold air. It will turn gray and often collect frost. Contrary to popular belief, it isn't because your freezer is too cold. Freezer burn can occur at a normal freezer temperature, too. But to freeze properly, you need proper freezer storage.
Use a white freezer-grade butcher's wrap or freezer-grade storage bag and be sure there is as little air as possible in the package. Always identify the item and write the date you froze it. The FDA has specific guidelines on how long they recommend freezing different foods before they lose flavor and texture.
Here are some examples:
Meat, uncooked steaks or chops
four to twelve months
Bacon and Sausage
one to two months
Meat, uncooked ground
three to four months
two to three months
Soups and Stews
two to three months
Freezing longer than recommended and freezer burn do not decrease the nutritional value of your food. The food may need help in the taste department, but you don't have to throw food away for being ugly or covered in frost. Let it thaw and give it a chance.
How Freezers Work
Internal refrigeration is fascinating. In order to create an artificial cold, you first must create a lot of heat. A freezer actually heats and pressurizes refrigerant liquids then converts them to vapor. This vapor cools the freezer's main chamber. The freezer then converts the vapor back to liquid and the process starts all over again.
It's similar to the water cycle. Imagine a little pond on a mountain leading to a series of brooks, creeks, and rivers. They all lead to the sea, where nature moves the warm water north and the cool water south. Clouds pick up the evaporated water, carries it back across the land and drops it, in the form of rain, back into the pond. The cycle then starts all over again.
Your freezer is one of the most important items in your home. It keeps your food safely stored and your frozen treats firm and delicious. It can even be used to purposely kill some of those bacteria that cause smells. Toss a stinky pair of gym shoes in a storage bag and put them in at normal freezer temperature and the next morning most -- if not all -- of the smell will be gone.
What to do in the Event of a Malfunction or Power Outage
Modern freezers can hold their cold for a very long time, even if they lose power. After an outage, a high-end freezer could potentially keep food frozen for weeks, provided you don't open the door. The thing to remember is safety. Freezer thermometers are inexpensive and will help you make sure your food is properly stored.
In the case of an outage, your food is safe at 32 degrees Fahrenheit or lower. Once the freezer compartment temperature rises above that, it's time to start thawing and cooking. You should store refrigerated foods at around 38 degrees Fahrenheit, so for a short time, your freezer will simply be a refrigerator thawing a whole bunch of food.
Once the temperature breaks 40 degrees Fahrenheit, your food will no longer remain safe. You'll need to make plans to either use it, give it to family and friends or donate it to your local shelter. Throwing food away should never be an option.
If your freezer breaks down, call a qualified technician. Refrigerant chemicals like freon can be toxic. They are also very dangerous. Split one of those copper lines and you'll find yourself either in the burn unit or being treated for frostbite for your now see-through fingers.
A Freezing Cold Conclusion
Freezing food has changed the world. We waste less and store safely. Harnessing the power of cold is one of humanity's greatest achievements. If there could be one conclusion, it is that everyone should learn and understand normal freezer temperature. Your food -- and your health -- depend on it.