Remove the stems from the peppers, cut them lengthwise in half, and remove the seeds. Cut crosswise into 1/2-inch-thick slices.
Put the peppers, vinegar, water, and salt in a medium-size nonreactive saucepan over medium-high heat. Bring to a boil, reduce the heat to medium, and simmer for 20 minutes. Remove from the heat and let steep until completely cool.
Pour the mixture into a food processor or blender and process until smooth. Strain through a fine-mesh strainer, pour into sterilized bottles, and secure with airtight lids. Refrigerate and let age for at least 2 weeks before using. The sauce can be stored in the refrigerator for up to 6 months.
Yield: 1 pint