Rinse the pepperoncinis under cool water, ensuring they are clean.

Using a small knife, make a slit in each pepper. This allows the brine to penetrate for better flavor.

In a large pot, combine the vinegar, water, salt, and sugar. Bring the mixture to a boil, stirring until the salt and sugar dissolve.

Add the garlic, oregano, and peppercorns to the boiling brine. I initially tried pickling without these but found the additional depth of flavor they brought was unmissable.

Place the pepperoncinis in a clean, sterilized quart jar.

Pour the hot brine over the peppers, ensuring they are fully submerged. Use a chopstick or butter knife to remove any air bubbles.

Seal the jar and allow it to cool to room temperature before refrigerating. The hardest part is waiting a week for the flavors to fully develop.