Usually when I make a shellfish stock I use uncooked shells to get as much flavour as possible, however it is very hard to extract raw crab meat from the shell and much easier to acquire discarded cooked shells. Luckily, you can make crab stock from already cooked crab shells and get a deeply flavoured broth.
This recipe was designed for Dungeness crab but should work for other kinds of crab as well. It was meant to go hand in hand with the crab risotto recipe. From one cooked crab you can make the stock, the risotto and even have some stock leftovers, perfect for saucing a pasta or forming the base of a bisque!
Crab Stock Recipe(6 cups)
If you haven't broken down the shells do that now, break each leg up as though you have cracked it. Any really big pieces should be broken in half.
Heat the tablespoon of oil over medium low heat and add the onion and celery. Sweat the onion and celery for 5 minutes. Add a pinch of salt, the crab shells and the thyme sprig. Cook the shells for a few minutes, stirring until fragrant. Add the wine and increase the heat to medium. Cook until half the wine has evaporated. Add 8 cups of cold water, the peppercorns, bay and tomato. Simmer for 40 minutes. Drain through a fine mesh. Cool it quickly in an ice bath and refrigerate or freeze.