Ingredients

• 5 ounces small (2- to 3-inch) fresh hot red or green chiles such as serrano or Thai (about 20), rinsed and patted dry
• 1 1/3 cups distilled white vinegar
• 6 tablespoons water
• 4 teaspoons sugar
• 1/2 teaspoon dried hot red-pepper flakes (optional)
• Special equipment: a 1-pt canning jar with lid and screw band; an instant-read thermometer

Instructions

1. Wash jar, lid, and screw band in hot soapy water, then rinse well. Dry screw band. Put empty jar on a rack in a boiling-water canner or a deep 5- to 6-quart pot and add enough hot water to cover by 2 inches. Bring to a boil, covered, then boil 10 minutes. Remove canner from heat, leaving jar in water. Heat lid in water to cover by 2 inches in a small saucepan until thermometer registers 180°F (do not let boil). Remove from heat. Keep jar and lid submerged in hot water, covered, until ready to use.
2. Make chile vinegar: Carefully remove jar and lid with tongs, then drain jar upside down on a clean kitchen towel and dry lid. Pack chiles into jar. Bring vinegar to a boil in small saucepan, then remove from heat and pour over chiles. Cool to room temperature. Wipe off rim of jar with a dampened clean kitchen towel, then top with lid and firmly screw on screw band. Chill sealed jar 2 weeks.
3. Carefully remove jar and lid with tongs, then drain jar upside down on a clean kitchen towel and dry lid.
4. Pack chiles into jar. Bring vinegar to a boil in small saucepan, then remove from heat and pour over chiles. Cool to room temperature. Wipe off rim of jar with a dampened clean kitchen towel, then top with lid and firmly screw on screw band. Chill sealed jar 2 weeks.
5. Make dipping sauce: Bring water and sugar to a boil in a small saucepan, stirring until sugar is dissolved, then stir in red-pepper flakes (if using), 2 tablespoons chile vinegar, and salt to taste. Remove from heat and cool to room temperature.
6. Bring water and sugar to a boil in a small saucepan, stirring until sugar is dissolved, then stir in red-pepper flakes (if using), 2 tablespoons chile vinegar, and salt to taste. Remove from heat and cool to room temperature.