Prepare jars by cleaning and sterilizing them in boiling water for about 10 minutes.

Combine the chopped fresh rhubarb, sugar, lemon juice, pectin, and brewed Earl Grey tea in a large pot.

Cook the mixture over medium-high heat until it reaches a rolling boil, stirring constantly.

After boiling for 5–10 minutes, look for a gel-like consistency as the jam simmers.

Test for set by placing a spoonful on a cold plate and checking if it holds its shape.

Fill sterilized jars with the jam mixture, leaving about 1/4 inch of headspace.

Seal jars by wiping rims clean and applying lids fingertip tight.

Process jars in a hot water bath for 10–15 minutes.

Cool jars completely before checking seals and store in a cool, dark place.