A full-flavored stock is often the secret to stellar soups, stews, and risottos, but it takes a bit of finesse to make really great vegetarian stock. Chowhounds have a few tricks for creating rich and savory broths without meat, and are discussing them on the new Vegetarian & Vegan board.
One strategy for deepening the flavor of vegetable stocks is to start by roasting the vegetables. ElsieDee saves vegetable scraps in the freezer; roasts them with carrots, celery, and quartered, unpeeled onions in olive oil "until they smell rich"; then deglazes the roasting pan with wine or water and simmers the vegetables for a few hours. will47 says this roasted vegetable stock is "more expensive than just using scraps, but I get good results." He often reduces the finished stock a great deal and freezes it in small cubes.
Another way to increase depth is to use ingredients rich in umami, along with vegetables. "I have found that dried shiitake mushrooms, seaweed, and Parmesan rinds (if it doesn't have to be vegan) are must-haves for a decent tasting veggie stock," DGresh says. goodhealthgourmet uses mushrooms and miso in combination, because she finds "that they balance each other so your stock doesn't become too salty or mushroom-y." IndyGirl likes the stock method in this recipe, which uses soy sauce to add umami.
A different approach, but one that works well as a base for soups, says meatn3, is to simply simmer raw, shelled nuts in water. This produces "a hearty yet clean flavor," meatn3 says.
Discuss: Homemade Stock