Wash your broccoli florets and set aside.
In a large stainless steel pot, combine your salt, vinegar, and water and bring to a boil. Stir salt until combined, then push off the stove.
Prepare your 5 pint jars: tightly pack with broccoli, then equally divide up the remaining ingredients: peppercorns, mustard and dill seed, garlic, and chile de arbol (stem removed).
Pour the hot brine over the jar contents, leave 1/2 inch of headspace. Wipe the rims, and apply your lids and rings until tight.
Process in a hot water bath for 15 minutes; remove from the heat, allow the jars to cool for 12-24 hours on a towel on your countertop.
Allow to sit in a cool, dark pantry for 3 weeks before consuming.