Makes about 10 cups
Place all ingredients in a 4- to 6-quart stockpot. Add enough cold water to cover, bring to a boil, and lower heat to simmer. Cook for 45 minutes to 1 hour. Vegetables should remain covered with water throughout the cooking process.
Strain through a fine-mesh strainer or colander lined with cheesecloth. (Do not press on vegetables.) Cool to room temperature and refrigerate. Stock can be refrigerated for up to 1 week or frozen for up to 3 months.