Step 1: Sterilize your canning jars, lids, and bands. Wash them thoroughly, then either run jars through a dishwasher on a hot cycle or boil them in water for 10 minutes. Keep jars hot. Simmer lids in hot (not boiling) water to soften the sealing compound.
Step 2: Wash and trim the green beans, snapping off the stem ends. You can trim the tail ends as well if desired.
Step 3: Bring a large pot of water to a rolling boil. Prepare an ice bath in a separate large bowl. Blanch the trimmed green beans in the boiling water for 2-3 minutes. Immediately transfer them to the ice bath to stop cooking and preserve crispness. Drain well.
Step 4: In a large saucepan, combine the white vinegar, water, pickling salt, and sugar (if using). Bring the mixture to a boil, stirring until the salt and sugar are fully dissolved. Reduce heat and keep the brine hot.
Step 5: Into each hot, sterilized pint jar, add 2-3 cloves of garlic, 2-3 sprigs of fresh dill, and any optional spices like mustard seeds or red pepper flakes. Tightly pack the blanched green beans vertically into the jars, leaving about 1/2 inch of headspace from the rim.
Step 6: Carefully ladle the hot pickling brine over the packed green beans, ensuring they are fully submerged and maintaining 1/2 inch of headspace. Use a non-metallic utensil to gently dislodge any trapped air bubbles by running it around the inside of the jar. Top off with more brine if necessary to maintain headspace.
Step 7: Wipe the rims of the jars clean with a damp cloth. Center the hot lids on the jars, then screw on the bands until fingertip-tight. Process the jars in a boiling water canner for 10 minutes (adjust for altitude if necessary).
Step 8: After processing, turn off the heat, remove the canner lid, and let the jars sit in the hot water for 5 minutes. Carefully remove the jars with a jar lifter and place them on a towel-lined counter. Let them cool completely undisturbed for 12-24 hours.
Step 9: Once cooled, check the seals. Lids should be concave and not flex when pressed. If any jar hasn't sealed, refrigerate it and consume within a few weeks. Label and store sealed pickled green beans in a cool, dark place for up to a year. For best flavor, wait at least 2 weeks before opening.