Make tomatoes last by preserving
The tomato is a much-loved and incredibly versatile fruit. Tomatoes are simply delicious eaten warm off the vine or chopped or sliced for salad, gazpacho or salsa. A bit more effort yields the freshest pasta sauce, savory tarts and soups redolent with its summery flavor.
To make this delectable fruit last long after the growing season is over, it can be dried, canned and frozen. Preserving saves money, reduces waste, ensures the quality of your food and creates interesting, tasty and useful foodstuffs.
Begin with the highest quality, perfectly ripe, disease-free fruit. Ideally, pick your tomatoes in the morning after the dew has dried but before the sun’s heat has softened and warmed the fruit. Preserve as close to harvest as possible to ensure the highest quality flavor and nutritional content.
Second, preserve what you like to eat. Each year I create pizza sauce, salsas, pasta sauces, spiced tomato jam and jars of whole tomatoes and tomato sauce. This season I am experimenting with oven drying sliced or halved Roma tomatoes, roasted with a variety of herbs, vinegars and a little fruity olive oil.
Once cooled, they are layered between parchment paper in freezer bags and frozen. Pulling them out on a dreary winter day, I envision adding the essence of summer to soups, sauces, salads and pizza.
Third, follow research-based recipes and processes to ensure safety and quality. Two excellent sources are a Penn State publication (https://extension.psu.edu/lets-preserve-tomatoes) and one from the National Center for Food Preservation, https://nchfp.uga.edu/.
Tomatoes can’t be sun-dried in Pennsylvania; our weather is too humid and not consistently hot enough. Instead use a dehydrator or oven set at 140-150 degrees with the door ajar 2-6 inches. Prepare larger tomatoes by steaming or dipping in boiling water for 30 seconds to crack and loosen the skin. Cool immediately in ice water, peel, and core. Slice ½-inch thick or cut into ¾-inch sections.
There is no need to peel cherry or small Roma tomatoes – just cut in half. Drying time is 6-24 hours. They will be leathery to crisp when dry. Once cool, store in labeled, airtight containers in a cool, dry, dark location and use within one year.
Freezing is easy and, if done properly, retains the most vitamins. Freeze items quickly and maintain a temperature of zero degrees or colder. Once peeled and cored, tomatoes can be frozen raw either whole, chopped, or as juice. Cooked down or stewed tomatoes can also be frozen.
Use freezer-safe, airtight, labeled containers. Allow 1 inch of space between the top of the tomatoes and the lip of the container. This allows for the expansion that occurs when moisture-rich items freeze. Thaw only in the refrigerator or in the microwave at the start of the cooking process
Another shelf-stable option is canning. Canned tomatoes in vacuum-sealed jars should be stored in cool, dry, dark locations. There is also an initial investment in equipment to process and store the harvest. A canning pot is needed for hot water bath processing of high-acid recipes. Low acid recipes require a pressure canner.
It is extremely important, for food safety reasons, to follow research-based processes and recipes. Tomatoes are on the cusp of what food scientists consider acidic foods, and failing to adequately increase the acidity can result in deadly botulism poisoning. To assure safe acidity in whole, crushed, or juiced tomatoes, add 2 tablespoons of bottled lemon juice per quart of tomatoes or 1 tablespoon per pint. Only use bottled lemon juice because the acidity level is constant.
Salsas are generally a combination of tomatoes and other low-acid vegetables – peppers, onions and herbs. There are tested recipes using lemon juice, vinegar or bottled lime juice to safely acidify salsa, which can then be safely canned. Without an acidifying agent, it is best to freeze salsa.
This article was first published in the Pittsburgh Post-Gazette on August 31st, 2018