Prepare the beans: Wash and trim beans so they fit neatly into a pint jar.
Pack jar: Stand beans upright in the jar, snugly but not crushed.
Add spices: Into the jar, add garlic, dill seed (or sprig), mustard seed, black peppercorns, and red pepper flakes if using.
Make the brine: In a small saucepan, bring water, vinegar, and pickling salt to a boil, stirring until salt dissolves.
Fill jar: Pour hot brine over beans, leaving ½ inch headspace. Remove air bubbles and top up with brine if needed.
Seal jar: Wipe rim clean and apply lid and band until fingertip-tight.
Choose storage method: Refrigerator pickles: Let cool, then refrigerate at least 2 weeks before eating. Canning: Process in a boiling-water bath for 10 minutes (pints), adjusting for altitude. Cool, check seals, and store.
