When we make veal stock, we wash the bones. Next, we blanch them. Any blood on the surface of the bones or in the meat will coagulate, and these impurities will float in the stock. We pour off the blanching water, rinse the bones again, and clean them. (If we had the time and space, we would blanch the bones twice, but it’s impractical.)
We then return the bones to the clean pot, add the appropriate amount of water, and bring it up to a gentle heat. It’s always important to have a gradual temperature change and to cook the stock at a low temperature. You don’t want to cook stock over too-high heat for three reasons: flavor, clarity, and yield.