Ingredients:
- 3 lbs fresh rhubarb, chopped into ½-inch pieces
- 4 cups granulated sugar
- ¼ cup fresh lemon juice
- 1 box (57 g) powdered fruit pectin
Instructions:
- Wash the rhubarb stalks thoroughly, trim the ends, and chop them into small, uniform ½-inch pieces. Combine the chopped rhubarb, sugar, and lemon juice in a wide pot and let it sit for 10 minutes to allow the sugar to draw out the natural juices.
- Place the pot over medium-high heat and stir constantly until the sugar is fully dissolved. Bring the mixture to a rolling boil.
- Whisk in the powdered fruit pectin and maintain a vigorous boil for 10–15 minutes, stirring frequently to prevent scorching. Use a potato masher occasionally if a smoother consistency is preferred.
- Continue boiling until the mixture reaches 220°F (104°C) on a candy thermometer. Verify the set using the plate test: drop a small dollop of jam onto a frozen saucer; if it wrinkles when pushed with a finger, it is set. Remove from heat immediately.
- Ladle the hot jam into sterilized jars, leaving ¼ inch of headspace. Wipe the rims clean, apply lids, and tighten bands.
- Process the jars in a boiling water bath for 10 minutes. Remove jars and let them sit undisturbed for 24 hours to ensure a proper vacuum seal.