Spicy Pickled Swiss Chard Stems

One large bunch of rainbow chard stems, cleaned and cut to fit into mason jar, about 3/4 inch from the lip

1/2 C. rice wine vinegar

3/4 C. distilled white vinegar

1/4 C. sugar or 3 T. maple syrup

1 1/2 teaspoons salt

1 1/2 T. sriracha

1/4 teaspoon celery seed, divided

1/2 teaspoon black peppercorns, divided

1/2 teaspoon yellow mustard seeds, divided

2 cloves garlic, divided

 

Add each half of the celery seed, peppercorns, mustard seeds, and garlic to each jar. (If just making one jar, this can all go together.) Pack chard stems tightly into jars. Bring vinegars, sugar (or maple syrup), salt, and sriracha to a boil, in a small saucepan until sugar and salt is dissolved. Then pour over chard stems. Let sit until cool, then put lids on and refrigerate. Wait two days before eating for flavors fully develop. Will last 1 month in refrigerator.