Prepare the Jars: Start by adding half the celery seed, black peppercorns, mustard seeds, and whole garlic cloves into each sterilized mason jar.

Pack the Stems: Next, tightly pack your cleaned and cut rainbow chard stems into the jars.

Make the Brine: In a small saucepan, combine water, rice wine vinegar, distilled white vinegar, sugar (or maple syrup), salt, and sriracha. Heat until boiling.

Pour the Brine: Carefully pour the hot brine over the packed chard stems in each jar.

Cool and Seal: Allow the jars to cool to room temperature before sealing them with lids.

Refrigerate: Place the sealed jars in the refrigerator and let pickles marinate for at least two days.