Sterilize jars with rings and lids using boiling water.
Trim grim beans.
In your saucepan, stir together the vinegar, water and salt. Add garlic and bring to a rolling boil over high heat.
Meanwhile, pack green beans, a sprig of dill, and pinch of red pepper flakes into jars.
Ladle or pour the boiling brine into the jars, filling to within 1/4 inch of the tops.
Seal jars with lids and rings. Place in a hot water bath so they are covered by 1 inch of water. Simmer but do not boil for 10 minutes to process. Cool to room temperature.
Test jars for a good seal by pressing on the center of the lid. It should not move. Refrigerate any jars that do not seal properly. Let pickles ferment for 2 to 3 weeks before eating.