Use a small, sharp knife to cut a slit down one side of each pepper. This will enable the brine to fully penetrate the peppers.Place the garlic, black peppercorns and bay leaves in the bottom of a large jar (half gallon) or divide between two quart-sized jars.Pack peppers into the jar as tightly as you can.
In a small pot bring the vinegar, water, sugar and salt to a boil. Bring vinegar, water, salt and sugar to a boil.Pour boiling brine over peppers until they are fully covered by the brine. Screw lid shut and let them sit until fully cooled.Transfer to the refrigerator. Let the pickled peppers sit for at least 3 days before using. For the best flavor let them sit for 1-2 weeks to allow the peppers time to fully absorb the flavors. The peppers will gradually become slightly shriveled over time as well as lose their bright color, turning a darker yellow/yellowish-green.Store in the refrigerator and make sure the peppers are always submerged under the brine. These pickled pepperoncini peppers will keep for several months in the fridge. You can also water bath can them and they will keep even longer.Makes about 2 quarts.
For Canning Pickled Pepperoncini: Follow the directions to the point in Step 2 where you pour the boiling brine over the peppers and spices in the jars. Fill the jars with the boiling brine leaving 1/4 inch head space. Stick a butter knife down into the jar to remove any air bubbles. Wipe the tops of the jars clean and secure them with lids and rings. Place them in a boiling water bath canner and process for 10 minutes (15 minutes if over 1000 feet elevation). Carefully remove the jars and let them sit undisturbed for 24 hours, then remove the rings and check the seals. If any are not sealed, store them in the fridge for up to 2 months. Store the remaining jars in a cool, dark place for up to 1 year.