When the tomato harvest peaks, home gardeners often face an abundance that quickly outpaces immediate consumption. Preserving this summer bounty is necessary to enjoy the vibrant flavor of fresh tomatoes long after the season ends. Successfully extending the life of a large harvest requires a variety of methods, from short-term storage to long-term preservation techniques like canning, freezing, and dehydrating. Strategic handling prevents waste and maximizes the value of the season’s yield.
Optimizing Short-Term Freshness
For tomatoes that are fully ripe and intended for use within a few days, the best storage location is the kitchen counter, not the refrigerator. Temperatures below 55 degrees Fahrenheit negatively affect cell membranes, leading to a mealy texture and reduced flavor compounds. The cold temperature also slows the synthesis of volatile aromatic compounds that give tomatoes their characteristic taste.
Store ripe, whole tomatoes at room temperature, ideally on a flat surface away from direct sunlight. Placing the fruit stem-side down helps reduce moisture loss through the stem scar. Avoid washing tomatoes until just before use, as excess moisture encourages mold and decay. If you must refrigerate softening tomatoes, allow them to return to room temperature before eating to improve flavor and texture.
Preservation Through Canning and Freezing
Canning and freezing are effective methods for handling high-moisture tomato products, especially for a large harvest. Canning provides a shelf-stable product that requires no electricity for storage, but it demands strict adherence to safety protocols. Although tomatoes are considered high-acid, modern varieties often have a pH level close to the safety threshold of 4.6, making acidification mandatory for home canning.
To ensure safety when using a boiling water bath canner, you must add a measured amount of acid to each jar before filling it. This is typically two tablespoons of bottled lemon juice or one-half teaspoon of citric acid per quart jar, or half that amount for pint jars. This addition lowers the pH sufficiently to prevent the growth of Clostridium botulinum, the bacterium that causes botulism.
Freezing is a simpler process that preserves the fresh flavor of tomatoes with minimal effort. Whole, washed, and cored tomatoes can be frozen on a tray until solid, then transferred to freezer bags for long-term storage. Freezing causes water content to expand, breaking down cell walls and resulting in a mushy texture upon thawing, which is perfect for use in cooked dishes like soups and sauces. For purees and sauces, the cooked product should be cooled, packaged in airtight containers leaving headspace, and then frozen, eliminating the need for added acid.
Preservation Through Drying and Dehydrating
Removing moisture from tomatoes concentrates their flavor and transforms them into a chewy, shelf-stable product. Using a dedicated electric dehydrator offers the most controlled way to achieve the correct dryness for long-term storage. Sliced or halved paste tomatoes, like Romas, are best for this method due to their lower water content.
Set the dehydrator temperature between 135 and 140 degrees Fahrenheit, which removes water without cooking the fruit. Depending on the thickness of the slices and the humidity, the process can take six to twelve hours. The tomatoes are finished when they are leathery and pliable, or crispy, but they should not feel sticky or have any remaining moisture.
Drying can also be accomplished using a conventional oven set to its lowest temperature, often around 140 degrees Fahrenheit, by propping the door ajar to allow moisture to escape. After the tomatoes are thoroughly dried, they must be cooled completely before storage. They can be placed in airtight containers for dry storage or submerged in olive oil, but oil-packed tomatoes must be kept refrigerated and consumed within a shorter period to prevent spoilage.
Handling Unripened End-of-Season Tomatoes
As the growing season closes, green, unripened tomatoes are often left on the vine. These fruits can be harvested before the first frost and ripened indoors to extend the fresh harvest for several weeks. Only tomatoes that have reached the mature green stage—firm and full-sized—will successfully ripen off the vine.
To ripen them, place the tomatoes in a single layer in a cardboard box or paper bag, separated by newspaper to prevent contact and absorb moisture. Ripening occurs best in a cool, dark location, such as a basement or garage, with temperatures around 55 to 70 degrees Fahrenheit. You can accelerate the process by adding an apple or a ripe banana, as these fruits release ethylene gas, which stimulates ripening.
For green tomatoes that will not ripen, they can be preserved immediately. Green tomatoes possess a firm texture and high acidity, making them excellent for pickling, chutney, or relish. They can also be sliced and frozen for use in recipes like fried green tomatoes, or incorporated into cooked dishes.