Take a quick peek inside the average American’s freezer and you’re bound to find some sort of frozen food ranging from simple vegetables to elaborate meals. Frozen foods make cooking easier by eliminating the work of dicing and chopping, saving time when preparing dinner for the family. They also make for tasty alternatives to bringing lunch to work or school. But as you’ll see, some kinds of frozen foods just can’t hold a candle to freshly made and are best left at the store.
The best frozen foods are those that freeze quickly or have enough moisture to make up for that loss post-freeze. Leafy greens, such as kale, are too delicate. “The freezing process destroys the cell walls, leaving you with limp produce,” says Jim Mumford, a chemical engineer who runs the website Jim Cooks Food Good. “Additionally, most greens are found chopped, which only works in certain applications. With the exception of spinach (used only for ravioli filling really), stick with fresh greens always.”
Vegetables with a high water content, such as celery, also don’t freeze well for much the same reason as leafy greens. Just thaw a bag of frozen chopped onions and compare the mushy, relatively flavorless result with a freshly chopped onion. “Freezing food is tricky business,” Mumford says. “When you freeze something, the water turns to ice (obviously). This means in food, the water inside will expand and turn into a crystal. When you defrost, that crystal melts, often leaving behind damage from the ice itself.”
Cruciferous vegetables such as these also are not fond of the freezer because of their relatively high water content. Thawed, these packaged veggies will be limp, not crisp and flavor will be less intense than fresh. Although you can’t restore that good-as-fresh snap when cooking, proper preparation helps a lot. Brussels sprouts, for instance, should not be thawed before cooking; those melting ice crystals will destroy the sprouts’ tender leaves. Instead, roast ’em in a preheated oven straight from the freezer.
There are oodles of frozen pasta meals sold at the grocery store, from spaghetti and meatballs to lasagna. And pasta generally holds its shape and texture during the freezing process, especially if it’s mixed with sauce. But if it wasn’t prepared al dente before being frozen, odds are that pasta may be a bit mushier than you like. What’s more, you can prepare a simple meal of spaghetti and jarred sauce in little more time than it would take to microwave the frozen equivalent.
Dairy-based dressings and sauces tend to separate during the freezing and unfreezing process, according to the United States Department of Agriculture. The result doesn’t just look gross; it also won’t taste the same. Manufacturers get around this by adding emulsifiers and other ingredients to keep everything together. That doesn’t make frozen foods with sauces and dressings inherently bad; just check the nutrition information before you buy.
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This advice applies to home cooks. “Many people (including myself) love canning and processing fruit at the end of a season, and the freezer seems attractive to those applications as longer term storage,” Mumford says. “Jams and the like are thickened with pectin, (akin to cornstarch in a gravy). Freezing alters the way pectin gels, and it never is the same again, resulting in watery, yet lumpy jam.”
Whatever you do, Mumford says, don’t freeze raw tomatoes. “Cooked sauce is a great idea to store in the chill chest, but an uncooked sauce (called passata) should not even be chilled, let alone frozen. When tomatoes get below 41 degrees, a chemical change occurs within the tomato, turning off certain flavor compounds forever.”
Check that expiration date: Most frozen foods can be stored safely in your freezer for up to three to four months, according to the United States Department of Agriculture.
Never freeze canned food: Cans are liable to burst in the freezer because water (and anything that contains water) expands when it freezes. If you want to freeze canned food, remove it from the can and transfer it to a freeze-safe container.
Make sure it’s cooked: Those “sear marks” you see on some frozen chicken breasts, veggie burgers, and other foods don’t necessarily mean those foods are fully cooked — they may be little more than cosmetic. Check package labeling before consuming anything that you’d normally have to cook before eating.
Freezer-burned food is okay to eat: Those leathery spots on that frozen pork chop indicate that air has penetrated the seal and dried out the food. Flavor may be affected, however.