Understanding Reactions
What happens when you put food in the freezer? It’s simple: the water in the food turns into ice crystals. This extreme cold slows down the chemical reactions that cause degradation of the food, but without stopping it completely.
Among these reactions is oxidation, which causes fruit to go brown and fats to go rancid, or brings a loss of vitamins. Frozen foods are spared from this—at least, for a time. When it comes to bacteria, freezing doesn’t destroy all of them, but forces them to hibernate. Once the food defrosts, they wake up and multiply again.
Know the Temperature of Your Freezer
The ideal temperature of a domestic freezer is approximately 0°F (-18°C). However, most freezers display a temperature between 14°F and 0°F (-10°C and -18°C), but the colder it is, the longer the food will keep. To know the temperature of your freezer, purchase a freezer thermometer at a hardware store.
Cool Before Freezing
The faster food reaches the freezing point, the better it is. Why? The ice crystals will be smaller and less damaging to the food’s cells.
If you want to freeze a warm or hot dish (spaghetti sauce, stew, soup, etc.), it’s preferable to divide the recipe into convenient portions (i.e., sufficient for a meal) and put them in freezer containers or bags. Avoid filling them too full because the food will expand as it freezes.
Then cool everything down by putting the bags or containers in a sink filled with cold water and ice. This pre-cooling also prevents warming up the entire contents of the freezer.
Wrap to Protect
Contact with air is the number one enemy of frozen foods. The freezer is a dry environment that dehydrates foods and causes what is known as “freezer burn.” Wrap your food in freezer bags (removing excess air), thick aluminum foil, or plastic or glass containers made for freezing.
If you freeze a dish directly in its cooking dish (such as lasagna or pie), cover it first with aluminum foil, tucking it in well, then wrap it in plastic film.
Please note that it’s not recommended to use margarine or yogurt containers and glass jars for preserves as they can crack.
This must be avoided. The same applies to meat, poultry or fish purchased at the grocery store and marked “defrosted product.” Why? To avoid the proliferation of bacteria that could make the food unsafe for consumption. The solution? Cook the food before freezing it again, as cooking destroys bacteria.
For example, it’s perfectly safe to make a shepherd’s pie with defrosted ground meat, then freeze the dish.
Indicate the Contents and Date
Frozen foods cannot be kept indefinitely. And there’s nothing more frustrating than to have no idea of what’s in a container that’s been frozen for months. With a permanent marker, write the name of the frozen foods on a label affixed to the container. Also include the date it went into the freezer, then apply the “first frozen, first defrosted” rule.
Defrost Safely
Never defrost a dish at room temperature, because it encourages the growth of dangerous bacteria. The safest way to do it is to defrost your food in the refrigerator.
The “Defrost” function on your microwave oven is a quick defrosting method. Make sure that the container used is microwave-safe. Another method is to put your dish in a sink filled with cold water. Make sure to change the water regularly so that it remains cold.
For sauces, soups and other types of liquid dishes, defrost the outside of the container or bag by putting it under running water, then slip the contents directly into a pot. Add a splash of water, then heat the dish slowly, breaking the block of ice gently with a spoon and stirring frequently.
Foods that can normally be kept at room temperature, such as bread, muffins, bars, cookies, fruit pies, etc., can also be defrosted at room temperature.
Optimize the Shelf Life of Frozen Foods
Sooner or later, frozen foods can become discoloured and rancid, or change flavour. The optimal shelf life of frozen foods varies from several weeks to several months, but it remains difficult to predict. It also depends on the nature and composition of the foods, the temperature of the freezer and its temperature fluctuations, as well as on the quality and airtightness of the containers.
Freezing Vegetables Correctly
Vegetables contain a ton of enzymes that will alter, slowly but surely, the colour, flavour and texture of the veggies, especially if they’re frozen for a period longer than 3 months. To deactivate these enzymes, you must blanch the vegetables, i.e., plunge them into boiling water for just a few minutes, then cool them down quickly. Some vegetables, such as peppers and tomatoes, don’t need to be blanched before being frozen.
Freezing Fruits
Put the fruits whole (strawberries, raspberries, blueberries, cranberries, blackberries) or sliced (apples, peaches, rhubarb) in a single layer on baking sheets lined with parchment paper, then put them in the freezer. Once the fruits have hardened, transfer them to freezer bags, removing as much air as possible.
It’s not necessary to blanch fruits before freezing them. However, some sliced fruit, such as apples, peaches, nectarines and apricots, tend to turn brown. To prevent this, sprinkle them with a little lemon juice.
Some foods don’t like being frozen as the ice crystals damage their texture too much.
Cooked egg whites... become very rubbery.
Some vegetables, like cucumber, lettuce, alfalfa sprouts, melons, radishes and sliced tomatoes... soften significantly.
Gelatin-based desserts... become spongy.
Mayonnaise... separates.
Cooked pasta and rice (served cold)... become coarse and crumbly.
Cooked potatoes, whole or in pieces (served cold)... come apart easily and become crumbly.
Yogurt... becomes more liquid and lumpy.
Avoid Freezer Burn
Do you have the bad habit of putting fresh meat and poultry bought at the grocery store straight into the freezer? You should avoid doing this because the plastic films used to wrap them are not perfectly airtight and can split when cold. After a while, the dry air of the freezer dries out the surface of the meat and causes rough, discoloured patches known as “freezer burn” to appear.
Even if this meat poses no health risk, its flavour and texture will be far from optimal. Protect your food and avoid waste by transferring the meat or poultry to freezer bags or covering them with a second layer of plastic film.
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Ground beef put in the freezer in its original packaging.
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Ground meat packed in a freezer bag, pressed to remove the air.
Save Energy
It’s preferable to keep your freezer almost full, rather than almost empty. In addition to ensuring better temperature control, this reduces energy consumption. Manufacturers recommend keeping them three-quarters full. When there are too many empty spots in your freezer, fill them with water bottles or ice cube trays.
