Name: Rhubarb Jam
Total time: 13 h
Ingredients: 2 pounds rhubarb , trimmed and cut into ½-inch pieces (7 cups); 3 cups (21 ounces/595 grams) sugar; ⅔ cup lemon juice (4 lemons)

Why This Recipe Works

We started our recipe by finding the perfect balance of tart rhubarb to lemon (which is added to help the pectin gel) and sugar; using twice as much lemon juice as most recipes call for helped the bright rhubarb flavor shine through. To reduce the rhubarb's natural stringiness without peeling it, we cut it into smaller pieces, which had the added advantage of reducing the cooking time. We found that rhubarb had enough natural pectin in it to help the jam thicken as it reduced, and because the proportions of the water and sugar and the pH of the jam all have to be correct for the pectin to thicken, adding acidic lemon juice lowered the pH of the jam and firmed up the pectin from the rhubarb into a jammy gel once cooled.

Before You Begin

Depending on the amount of trimming required, you may need more than 2 pounds of rhubarb to get 7 cups of cut pieces. In addition to sweet applications, this jam is great on a cheese board or added to a glaze for pork or duck.

Instructions

Place 2 small plates in freezer to chill. Combine rhubarb, sugar, and lemon juice in Dutch oven and bring to boil over medium-high heat. Cook, stirring often, until rhubarb is softened, about 5 minutes. Using potato masher, crush rhubarb gently, leaving some larger pieces intact. Simmer vigorously, stirring often and adjusting heat as needed to avoid scorching and splattering, until mixture is reduced by about half and registers 215 degrees, 18 to 20 minutes. Remove pot from heat.

To test consistency, place 1 teaspoon jam on chilled plate and freeze for 2 minutes. Drag your finger through jam on plate; jam has correct consistency when your finger leaves distinct trail. If jam is runny, return pot to heat and continue to simmer 1 to 3 minutes longer before retesting with second plate.

Place 2 pint jars in bowl and place under hot running water until heated through, 1 to 2 minutes; shake dry.

Using funnel and ladle, portion hot jam into hot jars. Let jam cool completely; cover; and refrigerate until jam is set, 12 to 24 hours. (Jam can be refrigerated for up to 2 months.)