Learning to Make Stock from Scratch

I wasted five years making terrible stock before I understood the three principles that matter. I'm posting this for anyone who finds their homemade stock weirdly flat or murky or bitter, because I did all of those things.

Principle 1: Cold water, slow build. Always start bones in cold water. The slow heating draws out albumin (a protein) gradually so it foams at the surface, where you skim it off. Starting in hot water causes it to emulsify throughout the stock, causing cloudiness. Skim the grey foam for the first 20 minutes after the boil begins.

Principle 2: Never boil, only simmer. After the initial scum removal, reduce to a bare simmer — you should see just occasional bubbles, not rolling movement. Aggressive boiling emulsifies fat into the stock, making it greasy and murky. This surprised me because I thought boiling meant extracting more flavor faster. It doesn't.

Principle 3: No bitter aromatics. Vegetables that cause bitterness: carrot greens, brassicas (broccoli, cabbage), turnips, too much celery leaf. Classic mirepoix (onion, carrot, celery stalk) is the baseline because it's bland and aromatic but not assertive. Add aromatics in the last hour only, not the beginning, to prevent bitterness from long cooking.