Stuff the jalapeños and garlic into 1 (1-liter) jar or divide between 2 (16-ounce) jars.
To a small saucepan, add the white vinegar, rice vinegar, water, sugar, bay leaves, coriander seeds, and salt. Simmer over medium heat until the sugar and salt dissolve, stirring periodically (about 5 minutes). Pour into the jar(s) with the jalapenos (I like to place the jars in the sink to catch drips). If the jalapenos aren't completely submerged in liquid, add water to cover.
Let the liquid cool to room temperature. Seal the jars and place in the refrigerator to chill for at least 1 hour or up to 2 weeks. The longer they sit, the more mellow they will become. Use on everything!
Notes
TO STORE: Store pickled jalapeños in the jar for up to 2 weeks; be sure to use a clean fork or other utensil to remove them from the jar.
TO FREEZE: Pickled jalapeños should not be frozen.