Freezing is a terrific way to preserve the bounty from your garden or local farmers market. Part of the appeal—for me, at any rate—is that you can do it in small quantities, as vegetables ripen to peak perfection. You don’t need a big batch (thus a big chunk of time), the way you do to make canning a worthwhile project.
For preserving optimum flavor and texture, preventing moisture loss in frozen foods is key. Otherwise, they can develop the frosty, dried-out patches called freezer burn, which is as unappealing as it sounds. That’s why you should always use packaging designed for freezing: Freezer-safe zip-top bags (be sure to remove as much air as possible before sealing) or plastic containers are one choice—you can stack them in the freezer; major brands such as Ziplock are made of polyethylene or polypropylene, which do not leach carcinogens or endocrine disruptors. Vacuum packing is another option. And if you prefer glass jars, the National Center for Food Home Preservation advises using dual-purpose ones, which are suitable for canning or freezing. Unlike regular glass jars, which break easily at freezer temperatures, the freezer-safe ones have been tempered to withstand extreme cold. According to the Ball Canning Jar Selector Guide, jars with “straight shoulders”—that is, no curve under the neck of the jar—are safe for freezer storage.
For freezing (as well as other preservation methods) choose produce that’s in great condition, with no spoiled or soft bits, and trim and wash it well. Think about how you’re going to use the vegetable—carrots for the soup pot, for instance—and cut it to the desired size. Preservation experts suggest that for best flavor and texture, frozen vegetables should be eaten within about eight months.
Food will deteriorate more rapidly, though, if your freezer isn’t at zero degrees or colder. “One easy way to estimate the freezer’s temperature,” notes the University of Nebraska at Lincoln, “is to check the consistency of ice cream stored inside the compartment. If the ice cream is not brick-hard, the temperature of your freezer is too warm.” And this may sound like a no-brainer, but always date and label frozen foods and use the oldest items first.
Strictly speaking, it’s not necessary to blanch vegetables (i.e., briefly cook them in boiling water) before freezing, but it extends their storage life by stopping the enzymes that cause ripening, helps remove bacteria and any remaining soil, brightens the color, slows nutrient loss, and makes the vegetables pliable, so you can pack them more tightly into a container. If you plan on doing lots of blanching and freezing, you may want to invest in a blancher pot (about $25 online), which has a basket insert, but any large pot will work fine.
To water-blanch vegetables
1. Fill a large bowl with ice water and set it aside. Fill a large pot with water (at least 1 gallon per pound of vegetables) and bring it to a boil. Add the vegetables and let the water return to a boil before setting your kitchen timer; blanching time depends on the type of vegetable, and more about that in a sec.
2. Use a slotted spoon or tongs to remove the vegetables from the boiling water and transfer them immediately to the ice water. Refresh the ice water if necessary so the veggies chill quickly and completely, then drain them well on clean kitchen towels.
To steam-blanch vegetables
A few vegetables, such as broccoli and winter squash, freeze better if they’re blanched in steam, and this is where a blancher pot, with its insert, can really come in handy. Otherwise, you can jury-rig a steamer with a large pot and a basket that will hold the vegetables at least three inches above the bottom of the pot and is big enough for you to spread the vegetables in a single layer. Simply put an inch or two of water in the pot and bring it to a boil. Place the vegetables in the basket in the steamer, cover the pot, and start keeping time immediately.
As far as blanching times go, you’ll find a convenient cheat sheet at the National Center for Home Food Preservation. Cut carrots for soups take just 2 minutes to blanch, for example, and okra, another prized soup ingredient (in my kitchen, at any rate) takes 3 to 4 minutes. Bell pepper halves—so nice to have for stuffed peppers—take about 3 minutes. Whole ears of corn take a bit longer—4 to 9 minutes, depending on size and whether you are cutting the kernels off the cobs or leaving them whole.
Tomatoes get their own category here, as they don’t need to be blanched unless you want to peel them before freezing. They can be frozen chopped or puréed, but I tend to take the path of least resistance and freeze them with peels on. Just rinse and dry them and cut off the stem scar. Then put them on a baking sheet and freeze until frozen solid before packing into freezer containers. Peeling frozen tomatoes for pasta sauces and stews is no big deal—just run them under warm water and the skin will slip right off.