Preserve fresh red currants with this tangy jam recipe from "Mes Confitures: The Jams and Jellies of Christine Ferber."
Place currants, sugar, and lemon juice in a large saucepan; stir to combine. Bring to a simmer over medium heat, 5 to 10 minutes. Transfer mixture to a large glass bowl; cover with a sheet of parchment paper, pressing down on the surface. Transfer to refrigerator; let chill overnight.
Place 3 clean 1/2-pint jars right side up on a rack in a boiling-water canner. Fill the canner and jars with hot water, about 1 inch above the tops of jars. Boil jars over high heat for 10 minutes. Remove and drain hot sterilized jars one at a time, reserving hot water for processing filled jars. Place jars on a wire rack set over a rimmed baking sheet.
Meanwhile, bring another medium pot filled with water to a boil over high heat and reduce to a simmer, then add clean lids and lid rings. Simmer lids for 10 minutes; do not boil, as this may cause problems in sealing jars. Drain lids and lid rings and set aside.
Pass currant mixture through a food mill fitted with a fine disk into a medium saucepan. Bring mixture to a boil over medium-high heat; let cook, stirring constantly, for 5 minutes, carefully skimming surface. Check set on a candy thermometer -- it should reach 220 degrees.
Fill jars with jam mixture up to the fill line. Put lids and rings on jars and tighten; do not overtighten. Reheat water in the canner until it reaches at least 180 degrees, within 10 minutes of filling the jars. Place filled jars into the canner one at a time, using a jar lifter that is securely positioned below the neck of the jar. Keep jars upright at all times.
Add more boiling water, if needed, so that water covers jars by at least 1 inch. Increase heat to high and cover. Once water begins boiling, heat jars for 10 minutes. Turn off heat and gently transfer jars to a wire rack set over a rimmed baking sheet, taking care not to tilt jars and spacing jars at least 1 inch apart. Avoid placing jars on a cold surface or near a cold draft.
Let jars sit undisturbed until fully cooled, 12 to 24 hours. Do not tighten ring bands on the lids or push down on the center of the flat metal lids until jars have cooled completely.
Once jars have cooled completely, test to make sure each jar is completely sealed. Press down on the middle of the lid with a finger. If lid springs up when finger is released, the jar is unsealed. Store sealed jars in a cool place for at least 2 and up to 4 weeks to allow flavors to thoroughly combine. If any of the jars are unsealed, store in the refrigerator and use within several days. Always refrigerate jam after opening.