Please read About Making Preserves and How to Process.

Combine in a medium bowl:

Cover and steep, above.

Unless you plan to plump the preserves, above, overnight, prepare a water-bath canner, gather all your canning equipment, place a couple of saucers in the freezer, and have ready 5 clean, hot half-pint jars.

Transfer the rhubarb mixture to a large heavy pot and bring to a boil.

Add:

Return to a boil, stirring frequently, then reduce the heat and simmer, stirring, until it reaches the jelling point, about 15 minutes. Remove from the heat and skim off any foam. If not plumping the preserves, ladle into prepared jars, leaving ¼ inch headspace. Wipe the rims. Place lids on jars and screw on rings until fingertip-tight. Process for 10 minutes. Let cool completely and store as directed.

If plumping the preserves, the next day return them to a boil before processing and canning.