Step 1
Soak Brussels sprouts in a large bowl filled with lightly salted water for about 15 minutes. Drain well.
Step 2
Sterilize the jars and lids in boiling water for at least 5 minutes.
Step 3
Divide the drained Brussels sprouts evenly between jars filling the jars about 3/4-inch from the top.
Step 4
Place 1 garlic clove and 1/4 teaspoon red pepper flakes in each jar.
Step 5
Bring vinegar water and pickling salt to a boil in a large pot over medium-high heat until the salt is dissolved about 5 minutes.
Step 6
Pour the vinegar mixture into the jars filling the jars to within 1/4 inch of the top.
Step 7
Run a knife or a thin spatula around the insides of the jars after they have been filled to remove any air bubbles.
Step 8
Wipe the rims of the jars with a moist paper towel to remove any food residue. Top with lids and screw on rings.
Step 9
Place a rack in the bottom of a large stockpot and fill stockpot halfway with water.
Step 9
Bring to a boil over high heat then carefully lower the jars into the pot using a holder. Leave a 2-inch space between the jars. Pour in more boiling water if necessary until the water level is at least 1 inch above the tops of the jars. Bring the water to a full boil cover the pot and process for 10 minutes.