Bring the apple cider vinegar, water, salt and sugar to a boil in a saucepan.
Boil gently for 5 minutes.
Meanwhile, mix together dill seed, black peppercorns, mustard seeds, red pepper flakes, and coriander seeds. Divide mixture between two glass canning jars.
Place 1 clove of garlic into each jar.
Tightly pack the green beans into the jars with the spices and garlic.
Pour the vinegar mixture over the green beans in the jars to within 1/4 inch of the tops of the jars. Wipe the rims, fix new two-piece lids in place to finger-tip tightness and process in boiling water bath for 15 minutes.
Carefully transfer to a rack to allow to cool completely.
Carefully remove the rings, wipe down, label, and store in a cool, dark place for up to a year. If there are any jars that don't seal, refrigerate immediately after processing. Let the pickled beans sit in the refrigerator for 2 to 3 weeks, before opening and eating.