Last Fall when living in Manhattan, I experienced fresh concord grapes for the first time and was dazed by the naturally jelly consistency and supersweet interior. I probably went through five pounds a week, so you can imagine my excitement when grapes started popping up at the farmers market here in San Francisco. Preserve the season's bounty by making homemade jam. A few serving suggestions: offer it for breakfast with English muffins and butter, or use it as a filling for cakes or mix it into vanilla frosting. Slip some in a peanut butter sandwich, and you'll find that PB&Js never tasted so good.
Fall back in love with this sandwich staple when you get the recipe.
2 glass jars with metal seals and lids
1 stainless steel canning rack
1 jar funnel
1 magnetic jar lifter
To sterilize jars: Wash jars, metal seals, and lids in soapy water, then rinse. In a deep pot or pressure cooker, cover the jars with enough water so they are completely covered. Bring to a boil, and sanitize for 10 minutes. Turn off heat, but keep jar in the pot to say warm. If the jars are not warm when you pour in boiling jam, they might crack.
To make jam: Chill a plate in the freezer to use later for testing the jam's consistency. In two bowls, separate the skins from the flesh by pinching the grape and allowing the flesh to pop out. In a food processor, combine grape skins and sugar, and puree until smooth.
Combine grape skin mixture, grape flesh, and lemon juice in a bottom heavy, medium to large pot. On medium heat, keep mixture at a simmer for 20 minutes, stirring occasionally to prevent scorching.
Place a fine mesh sieve over a clean metal bowl, and pour mixture into mesh sieve. Using a rubber spatula, force the liquid through the sieve, discarding the seedy, dry pulp remains.
Return strained mixture to pot, and simmer over medium heat for 10 minutes. Whisk in pectin, and cook for 1 minute. Take chilled plate out of freezer and dab a small amount of jam on plate. Return plate to freezer for 1 minute. If jam has gelled and does not slide down when the plate when tilted, then it is done. However, if the jam slides down, continue to cook jam for a few more minutes, and try the freezer test again. Continue cooking, until jam reaches the desired consistency.
To process jars: Using the jar lifter, remove warm glass jars from warm water. Place funnel over jar, and pour jam mixture into jar, leaving about an inch of headroom. Place seal over the top of the jar, and screw on the lid tightly. Using the jar lifter, return jars to the water-filled deep pot. Cover the pot and bring it to a boil. Boil jars for 10 minutes. Turn off heat, remove jars, and set them on the counter or a wire rack to cool. You should hear a snap as they cool, signifying the seal has inverted and jars have processed correctly. Sealed jams should last sealed for up to 12 months and once opened, they will last several months refrigerated.