Preserved grapes can used for baked goods and desserts, as well as savory sauces to serve with roasted and grilled meat and poultry. This article offers a brief overview of the methods for preserving fresh red or green table grapes. Preserve fresh table grapes and grape juice by freezing, canning, pickling, drying, or fermenting into wine or vinegar.
Until you are ready to prepare fresh grapes for preserving, store them unwashed in a very cold (32°F to 40°F) refrigerator, in very humid conditions (80%-90% RH), such as plastic bags with holes. Grapes readily absorb odors; store them away from foods such as bananas, apples, onions and cabbage. Grapes will stay fresh about one week, but examine the bags every couple of days for visible moisture; immediately air out bags with any condensation. As with all fresh produce, grapes are best preserved within 24 hours after harvesting.
To prepare grapes: One pound of grapes is equivalent to two dry pints, four cups whole, three cups halved, 2½ cups purée, or 1½ cups juice. Wash fruit and pull off stems. Discard grapes that are moldy or soft from rotting. Leave grapes whole or cut in half and remove seeds as directed in the recipe. You may wish to pre-treat light-colored green grapes for browning, which can occur especially near the stem.
How to pre-treat light colored green grapes for browning: Prepare a solution using 3,000 mgs crushed Vitamin C tablets, or four teaspoons (five grams) citric acid in a gallon of water. Or use plain apple juice. Soak prepared fruit for five minutes; drain and proceed with recipe.
Methods for Preserving Fresh Table Grapes
Fresh or frozen grape juice: Prepare about 3½ pounds grapes per quart, cut in half and removed seeds if present. Measure fruit into a saucepan, crush slightly, and add one cup hot water for each quart of fruit. Cook over medium heat, stirring frequently, for 10 to 15 minutes or until soft. Transfer to a fine mesh strainer, or colander lined with a double layer of dampened cheesecloth, and set over a bowl. Drain undisturbed for two hours. Discard solids in the strainer (or use to make jam or fruit leather). In a saucepan, combine juice with one tablespoon sugar (or to taste). Sugar may be omitted, but helps retain color and flavor. Refrigerate juice and use within three days, or transfer to freezer-safe container and freeze up to 12 months. For shelf stable storage, process grape juice in a boiling water bath canner.
Canned grape juice: In a saucepan over medium-high heat, heat freshly made grape juice to 190°F; adjust heat as needed and keep juice at 190°F for five minutes. Do not boil. Keep juice hot while filling jars; adjust headspace to ¼-inch. Process pints or quarts for 15 minutes (at 0 to 1,000 feet).
Verjus or verjuice (“green juice”): In this case, verjuice refers to underripe grapes (either red or green), not green grapes. The following is an old French recipe that macerates fruit with sugar and alcohol. Coarsely chop about one pound underripe red or green grapes. Press through a fine mesh sieve to make one cup juice. Place juice in a sterilized one-quart jar. Add 1⁄two cup chopped grapes, 1⁄4 cup granulated sugar, two cups 80-proof vodka, and 1⁄two cup white vinegar. Cover jar and refrigerate for two months. Strain liquid and transfer to a sterilized jar. Discard solids. Verjuice keeps indefinitely. Use to deglaze pan sauces for poultry or ham.
Grape jelly: In a heavy stainless or enamel saucepan, stir together one cup grape juice and 3/4 cup granulated sugar. Boil over high heat, stirring constantly, until sugar dissolves. Refrigerate and use within one month. For longer storage, keep jam hot while filling jars; adjust headspace to ¼-inch. Process half-pints or pints for 10 minutes (at 0 to 1,000 feet).
Canned whole grapes (raw pack): For each quart (two pints), prepare four cups whole grapes and about two cups light syrup. To make syrup, in a saucepan, stir together stir together two cups water and 1/2 cup sugar; bring to a boil and stir until sugar has dissolved. Keep liquid hot while filling jars. Ladle a small amount of hot canning liquid into a hot jar. Add prepared (raw) grapes; pack tightly without crushing, and add hot liquid to cover. Adjust headspace to ½-inch. Process raw pack grapes in pints for 15 minutes or quarts for 20 minutes (at 0 to 1,000 feet).
Pickled grapes (hot pack): Prepare 2¼ pounds fruit per quart. In a saucepan, stir together 1½ cups sugar, 1/2 cup vinegar, 1/2 cup grape juice or water, 1/2 stick cinnamon, 2-3 whole cloves, and one teaspoon black peppercorns. Bring to a boil, reduce heat, and simmer 10-15 minutes. Remove and discard spices. Add prepared whole grapes. Cook five minutes. Cool, cover, and refrigerate up to one month. For longer storage, fill hot canning jars with hot grapes and pickling liquid; adjust headspace to ½-inch. Process hot pack pickled grapes in pints or quarts for 15 minutes (at 0 to 1,000 feet).
Dried grapes (raisins): Prepare grape halves; remove seeds if present. Place grapes cut side up on drying trays. Preheat an oven or food dehydrator to 130°F to 140°F. Dry grapes until pliable for snacking, or until crisp for longer storage. Cool until no longer warm; store in an airtight container in a cool, dry place for about 2 months. Freeze for longer storage.
Dried grape leather: Leathers are made from purées that are spread thin and dried until supple and chewy. For best results with grapes, first prepare juice from seedless grapes; then make leather from the leftover strained fruit and skins. If desired, add one tablespoons sugar or honey, and/or one tablespoon lemon juice to every cup of fruit purée. Preheat oven or food dehydrator to 130°F o 140°F. Line drying tray with plastic wrap. Spread purée 1⁄4 to 1⁄2 inch thick on liner. Dry until leather is evenly pliable and firm with no soft spots. Peel from liner while still warm. Cut or roll into serving pieces. Cool before wrapping pieces individually. Store in an airtight container in a cool, dry place up to 2 months. Freeze for longer storage.
Red or white wine: Making wine is slightly more complicated than making vinegar. If you try and fail, at least you might end up with vinegar. If you put freshly squeezed, unheated (raw) grape juice inside a closed vessel (without air), the wild yeasts from the grape skins convert the juice (sugars) to wine (more specifically, alcohol, or mostly ethanol). If you start with high-quality product and clean conditions, you get a better product rather than simply allowing overripe fruit to spoil. Here is the basic process for fermenting wine as well as cider or beer.
Grape (wine) vinegar: Dissolve 1⁄4 packet wine or beer yeast in a small amount of tepid water. Let stand 10-15 minutes, or until foamy. In a clean and sanitized 1-quart glass jar, add two cups room-temperature (red or white) grape juice. Cap it and shake to mix thoroughly. Add more juice, filling the jar no more than 3⁄4 full. Cover the jar with a clean piece of clean cheesecloth (or a towel). Store at warm room temperature (70°F to 75°F), away from light (for example, in a cupboard). It should be ready in 2-4 weeks, or when it tastes pleasantly tart. Use within 12 months.
For more information about food preservation methods and recipes, see the book The Home Preserving Bible by Carole Cancler, available from booksellers everywhere.