Freezing food is a great way to extend its shelf life. You can freeze individual ingredients or preserve entire meals that can be reheated quickly. Chef Frank Proto from the Institute of Culinary Education provided us some tips for freezing food safely.
1. To freeze most vegetables, cut them to size and then blanch.
Most vegetables (including broccoli, green beans, cauliflower, and Brussels sprouts) should be blanched first to preserve color and flavor. First, cut the vegetables to the size you’ll want to cook/serve later. Then, boil briefly in salted water—how long depends on the type of vegetable and the size of the pieces, but for the vegetables we've mentioned here, three minutes (or until tender) should do the trick. Next, drain the vegetables and immediately cool in an ice bath, which stops the cooking process. Drain again.
Before your vegetables get anywhere near the freezer, make sure they're dry: The less water your ingredients retain, the better they’ll hold up in the freezer and resist harmful freezer burn. You can use a salad spinner to remove water and/or pat individual pieces dry with paper towels.
Next, spread the individual pieces out on a parchment-lined cookie sheet and freeze for around an hour. This will prevent them from turning into one big frozen clump in the freezer. Finally, store food in a freezer bag or airtight container, removing as much air as you can. You should only use plastic containers or tempered freezer-safe glass, like Pyrex.
How to Use After Freezing: Frozen vegetables can be used straight from the freezer. You may need to cook them slightly longer to get rid of any water they’ve retained, but they can be incorporated into stir-fries, soups, and other dishes quite successfully.
2. Skip blanching for tender vegetables and fruits.
Tender greens like spinach can be frozen without blanching. Bell peppers and sliced or diced onions can, too—just clean and dry them as well as possible. Fruits can be frozen raw as well. Just spread them out on a parchment-lined cookie sheet and “pre-freeze” to avoid clumping. Then bag them, removing as much air as you can.
How to Use After Freezing: Fruits can be eaten or thrown into smoothies still frozen, or defrosted for a snack. You don’t want to defrost and then refreeze, though, so take out only the amount you’ll want to eat in one sitting.
3. Make sure soups and stews are cool before freezing.
Placing hot items in the freezer can raise the ambient temperature, which can cause issues like freezer burn if it leads to items unfreezing and refreezing—so let cooked soups and stews cool before placing them in the freezer.
For maximum safety, you want to cool the food as quickly as possible so it spends a minimal amount of time in the “danger zone” of temperature where bacteria can grow. To do this, you can divide hot items into smaller containers—more surface area means things will cool faster, so a flat freezer bag will cool faster than a deep pot or bowl.
You can also use an ice bath to quickly bring down the temperature of prepared foods. Fill the sink (or a large bowl) with cold water, add ice, and dip the entire cooking vessel into the cold water, making sure the water level doesn’t rise high enough to get into your food. Stirring the hot food inside the cold water bath will reduce its temperature much faster than sitting out at room temperature or in the refrigerator.
How to Use After Freezing: Prepared foods like soups and stews can be heated up in a pot right from the freezer. You may need to microwave them for a few seconds to release them from their containers—otherwise just heat in a pot until they reach serving temperature.
4. Wrap meats with plastic and foil before freezing.
Raw vacuum-sealed meat can be frozen as-is. Otherwise, wrap meat tightly with plastic wrap and foil. Don’t forget to label any items you won’t be able to identify later. Putting the dates on the foil will also help you remember what items are oldest, so you can use them first.
Chef Frank also recommends sticking your newest items deep into the freezer. This will freeze them faster, and will also encourage you to first use the older items that are up front in the freezer.
He also advises against packing your freezer too tightly. While modern freezers can be filled quite a bit, you still want to provide enough room for air to circulate—otherwise the back of the freezer will stay cold, while the front will get relatively warm quickly, especially if you’re repeatedly opening the freezer.
How to Use After Freezing: Frozen meat should be thawed in the refrigerator overnight. Large pieces of meat like a chicken may need two days in the fridge, while a large turkey could take three. The refrigerator provides a safer temperature for thawing compared to letting food sit out on the counter. If you need to speed up the process, you can run the frozen meat under cold water.