01 - Place all vegetable scraps, optional potato, and fresh vegetables into a large stockpot.
02 - Incorporate bay leaves, parsley, thyme, black peppercorns, garlic, salt, and vinegar or lemon juice if using.
03 - Pour in cold water and stir gently to combine all components evenly.
04 - Heat over high flame until the liquid reaches a rolling boil.
05 - Lower heat to maintain a gentle simmer and continue cooking uncovered.
06 - Remove any foam rising to the surface during the first 10 minutes of simmering.
07 - Allow broth to simmer uncovered for 60 minutes, stirring occasionally for even extraction.
08 - Remove from heat; let cool briefly before straining through a fine-mesh sieve or cheesecloth into a container, discarding solids.
09 - Taste the broth and adjust salt or acidity as needed.
10 - Use immediately or refrigerate up to 5 days, or freeze for up to 3 months.