Combine the chopped rhubarb, sugar, and water in a medium saucepan.

Bring the mixture to a boil over medium-high heat, stirring to dissolve the sugar. Reduce heat to low and simmer for 15-20 minutes, or until the rhubarb is very tender and has released its color.

Remove the saucepan from the heat. Strain the mixture through a fine-mesh sieve lined with cheesecloth into a clean bowl or pitcher. Press gently on the solids to extract as much liquid as possible, but do not force through the cheesecloth.

Discard the rhubarb solids. You should have a bright pink syrup.

Carefully ladle the hot syrup into the sterilized half-pint canning jars, leaving about 1/2 inch headspace.

Wipe the rims of the jars clean with a damp cloth. Place the lids on and screw on the bands fingertip tight.

Process the jars in a boiling water bath for 10 minutes, adjusting for altitude if necessary. Remove jars from the canner and let them cool on a towel undisturbed for 12-24 hours. Check for seals before storing.