In the last warm weeks of summer, it's hard to imagine that today's tomatoes, corn, peaches and other late-summer bounty will soon be just memories.
But wait, they don't have to be. With a bit of forethought, and a bit of time, we can safeguard some of this magnificent produce and draw upon it all winter long.
When you preserve food, you are using techniques to stop its natural decomposition, killing or preventing the growth of microbes. It's important to follow experts' directions closely for safety and food quality.
Four basic ways to preserve late-summer fruits and vegetables:
The simplest and most accessible way to preserve all kinds of produce quickly. The two most critical things about freezing produce are to freeze it as quickly as possible, and to do so in freeze-grade bags and containers.
Chill food before freezing it, so it will freeze faster, says Eugenia Bone, author of books including "Microbia" (Rodale, 2018), "The Kitchen Ecosystem" (Clarkson Potter, 2014) and the James Beard-nominated "Well Preserved" (Clarkson Potter, 2009). "The slower the freezing process, the larger the ice crystals, which can cause the cell walls of the produce to rupture: This is what makes defrosted foods mushy," she says.
To prevent freezer burn, which can affect the taste and texture of food, use plastic bags, wraps or containers designed specifically for the freezer.
If you use a container, leave the right amount of headspace, since food will expand when it becomes frozen. Too much extra space will result in trapped air. Freezer-proof, zipper-top bags are terrific since you can label them easily, squeeze out excess air and freeze them flat on a tray. Once frozen, they can be stacked vertically or horizontally to save space — and they can be washed and reused.
Consider blanching fruits and vegetables — putting them in boiling water and then shocking them in a bowl of ice water — before you freeze them, to enhance their quality after they thaw. Fruits with skins can be blanched, pitted and peeled before freezing so they are ready to use once defrosted.
To avoid clumping later, spread the fruit out on a tray or cookie sheet and then place it in the freezer. When it is frozen, transfer it to freezer-proof containers or bags.
A note on tomatoes: If you freeze them whole, the skins will slip off when they thaw, as if you had blanched and peeled them. Or try roasting them first, and then freezing them.
Most vegetables and pretty much all fruit will have a softer texture when thawed, depending on how cold your freezer is. The closer to 0 degrees Fahrenheit it is, the better your frozen product will be and the longer it will keep. So plan to use vegetables in cooked preparations. Frozen fruit should be used either in its frozen state in smoothies and icy desserts, or, if you are thawing it, in a pie, crumble or other baked dessert.
Late-summer vegetables to freeze: beans (string, pole, green, yellow, wax), broccoli, Brussels sprouts, cabbage, cauliflower, corn, eggplant, herbs, okra, tomatoes, zucchini.
Late-summer fruit to freeze: apples, berries, cherries, figs, peaches and nectarines, plums.
There are two main ways to can produce: boiling water bath and pressure canning.
The water bath method involves packing glass canning jars with food, leaving adequate headroom, and heating the jars in a pot of boiling water for a prescribed amount of time. The heat drives any air from the jar, sterilizing the food and creating a vacuum that causes the rubber flange on the lid to seal. This method works best with naturally acidic foods like fruits, and alkaline foods that have been acidified, like pickles. Low-acid foods like vegetables and mushrooms cannot be canned using this method unless acidified.
The pressure canning method requires a pressure canner (not a pressure cooker), and involves pressurized steam heat, which can reach a higher temperature than boiling. At these temperatures, alkaline foods can be safely canned without acidification. Pressure canners should be purchased based on the type of stove you have and the amount of food you plan to can. Bone's book "The Kitchen Ecosystem", for instance, has advice on how to choose a pressure canner. Similar to water-bath canning, the heat pushes air out of the food and jars, sterilizing both and creating a vacuum seal.
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It is critical to follow directions for each canning method, and for each type of produce you want to preserve. Whichever method you use, always test the seal.
"The best way to test your seal," says Bone, "is to wait until the jar has cooled totally. Then remove the band and see if you can lift the jar by the rim of the lid. If you don't spill the contents of your jar all over the counter, then your seals are good."
Improper canning can result in the growth of harmful spoilers, so find a reliable source to follow. Bone recommends the National Center for Home Preservation website .
Late-summer, high-acid foods for boiling water bath canning: apples, berries, cherries, figs, peaches, pears, plums, tomatoes (with additional acidification).
Late-summer, low-acid foods for pressure canning: beans (string, pole, green, yellow, wax), carrots, corn, okra, bell peppers.
There are many methods. You can prepare fermented pickles, which use salt or salt brine, and quick pickles, which use vinegar. Pickling acidifies the vegetables so they can be safely water-bath canned.
You can pickle whole vegetables, like green beans or okra, or you can make chutney or relishes with chopped produce plus some seasonings. Most of the techniques and rules of regular canning apply.
There are some pickling methods that don't involve canning, like refrigerator pickles. These don't have the shelf life of processed pickles, and must be kept in the fridge, but they will extend the life of the produce somewhat. Refrigerator pickles offer a fresh flavor and usually a crisp texture.
Late-summer foods to pickle: apples, Brussels sprouts, carrots, corn, cucumbers, eggplants, green tomatoes, hot chili peppers, onions, pears, plums, watermelon rind.
Whatever food you are drying should be just ready to eat, not overripe or under-ripe, and without bruises or dings. In some cases, produce to be dried should be pretreated — either blanched, or dipped in solutions to retain color and texture.
Again, find specific directions for each food to ensure quality and safety.
Drying methods include air drying, oven drying and using a dehydrator. A dehydrator is the most reliable. If you think you will be drying foods regularly, invest in an electric dehydrator. Bone recommends one with an enclosed thermostat which ranges from 85 to 160 degrees Fahrenheit, a fan or blower to circulate air, and trays made of plastic.
Fruit can be made into fruit leather.
Late-summer produce to dry/dehydrate: apples, cherries, corn, figs, grapes, hot and sweet peppers, mushrooms, okra, peaches, pears, plums, shell beans, smaller tomatoes.