Wash jars and screw bands in hot soapy water; rinse with warm water.

Fill the canner with water and place the jars on the rack.

Cover the pan and bring to a simmer over medium heat.

Reduce heat and keep the jars hot while you prepare the jam.

Prepare the rhubarb by washing, removing the leaves and chop the rhubarb into 1 inch pieces.

Combine the chopped rhubarb and the oreange juice in a non reative 4 quart sauce pan, bringing to a boil and cooking for 2 minutes or until the rhubarb is tender.

Stir in the pectin and the butter to the softened rhubarb.

Bring to a full rolling boil, stirring constantly.

Add the sugar to the rhubarb and return to a full rolling boil and boil for 1 minute stirring constantly.

Remove from the heat and skim any scum that has risen to the top.

Ladle the hot jam to within ¼" of the hot, clean jars. Wipe the rim with a wet, clean cloth. Add a clean lid and a clean ring. Finger tighten the ring.

Return the filled jar to the hot water canner.Repeat with the remaining jars, returning each filled jar to the water bath canner when filled.

Process the jars for 10 minutes.

Remove the jars from the hot water canner and allow them to rest on a towel lined counter.Once the jars have cooled, check each lid for flex. If a jar flexes, place it in the refridgerator.