Gather ingredients: vegetable scraps (onion skins, carrot ends, celery tops, leek ends, garlic skins), plus fresh vegetables if desired (carrot, celery, onion, mushrooms, herbs)
Avoid: potatoes, cruciferous vegetables (broccoli/cauliflower/cabbage) if you dislike bitterness, very fibrous stems (if not chopping), and anything spoiled or heavily browned
Wash scraps thoroughly; remove any dirt
Chop large scraps into smaller pieces
Optional: lightly roast (optional) browned scraps/vegetables at 425°F / 220°C for 20–30 minutes to deepen flavor
Add to a stock pot: 1 part scraps to 2–3 parts water (enough to cover by 1–2 inches)
Add aromatics: 1–2 halved onions, 2–4 chopped carrots, 2–4 chopped celery stalks (optional)
Add herbs/spices: 1–2 bay leaves, 1–2 tsp whole peppercorns, 1–2 tsp dried thyme or parsley stems (optional)
Tie herbs (optional) in a bundle with kitchen twine for easier removal
Bring to a boil, then reduce to a gentle simmer
Simmer: 45–60 minutes for lighter stock; 1.5–2 hours for richer stock
Skim foam if needed
Taste near the end; add more salt only if you plan to reduce it later (otherwise keep it unsalted)
Strain through a fine-mesh sieve or cheesecloth
Cool quickly: place pot in an ice bath or transfer to shallow containers
Store: refrigerate up to 4–5 days
Freeze: in containers or freezer bags up to 3–4 months
Optional reduction (for concentrated stock): simmer strained stock to desired strength, then cool and store