Fish Stock

There is a long-held belief in French cooking that fish stock must not be cooked for more than 20 to 40 minutes. As a young cook, I ignored this rule and cooked my fish stocks for long hours, just as I did meat stocks. As I learned more, I persisted in what turned out to be a very satisfactory habit.

I eventually learned where the “don’t overcook stock” rule came from. French restaurant chefs use flatfish—flounder and sole—for their stocks, because they cook these fish in quantity a