Prepare a water-bath canner and bring it to a simmer (180° F) over medium heat. Heat 6 (½-pint) jelly jars in the canner, either upside down or on their sides. In a saucepan, add enough water to cover the lids and bands and bring to a simmer (180° F) over medium heat; do not boil. Keep lids hot until you’re ready to apply them.
Pour the vinegar into a large saucepan and bring to a simmer over medium heat. When the vinegar begins to steam, use tongs to remove the jars from the canner. Place ¼ cup chiles pequins, a garlic clove, a sage sprig, a teaspoon of sea salt and a teaspoon of peppercorns in each jar. Ladle the hot vinegar into the hot jars, leaving a ¼-inch headspace. Wipe the jar rims clean and apply the lids and bands.
Return the jars to the canner, with enough water to cover the tops of the jars by 1 inch. Bring to a boil and process for 10 minutes. Uncover the canner and turn off the heat. After 5 minutes, remove the jars and let them cool.
Allow the pepper sauce to sit untouched for 24 hours, then check seals, remove bands and store in a cool dry place for up to a year. An opened jar, capped tightly, can be stored at room temperature or transferred to a shakertopped bottle. Pepper sauce can be diluted by adding a bit more vinegar (no need to reheat the vinegar prior to adding).