Note: While most herbs and vegetables work well in stock, some may give it an off or bitter flavor. Avoid cruciferous vegetables like broccoli, Brussels sprouts and cabbage. Make sure your vegetables pieces are the size of a quartered onion, or smaller, so they have enough time to cook. When adding herbs go light on ones with stronger flavors like rosemary and sage.
To make ahead: Refrigerate cooled stock in an airtight container for up to 1 week or freeze for up to 3 months.