The Gibson

Whisk 1/2 cup apple cider vinegar, 1/4 cup red wine vinegar, 1/4 cup unseasoned rice vinegar, 1/4 cup white wine vinegar, 1/4 cup sugar, 4 teaspoons kosher salt, 1 tablespoon black peppercorns, 1 tablespoon coriander seeds, 1 tablespoon juniper berries, 1/8 teaspoon crushed red pepper flakes, 1 halved garlic clove, 1 bay leaf, and 1 1/4 cups water in a nonreactive container until salt and sugar dissolve. Add 1 pound small pearl onions, peeled, trimmed. Cover; chill at least 1 week and up to 3 months. Flavors will deepen with time.