Before you start, prepare your pickle jars. I like to use mason jars, but any glass jar that a canning lid fit on will work as well.

• Wash and dry your rhubarb stalks. Then using a sharp knife cut the stalks into 1-2 inch pieces. I like to cut my at an angle but you can cut them however you like.
• Pack the pieces into your prepared jars, leaving a 1-inch gap at the top.
• Divide the mustard seeds and red pepper flakes between the jars. And Set them aside while you prepare your pickling liquid.
• In a small saucepan combine the vinegars, sugar, cinnamon stick, bay leaves, coriander, cardamom, allspice, cloves, and ginger.
• Over medium-low heat cook the mixture, whisking often until the sugar has completely dissolved and the mixture is near boiling.
• Once the mixture is hot, strain out the cinnamon stick, bay leaves, and whole cloves.
• Pour the hot brine into the jars until it covers the rhubarb pieces.
• Screw on the jar lids and allow them to cool slightly before moving them to the refrigerator.
• Allow the pickled rhubarb to sit in the fridge for at least 24 hours before serving. To get the best flavor I would recommend letting them sit for 3 days.