In the case of chicken or beef stock, the stock comes from cooking bones in water on low heat, for several hours. With vegetable stock, there are no bones to cook, so the richness of the stock comes from the variety of vegetables you use. A big thanks to Hank Shaw who shared his method for making veggie stock with me, after tiring of hearing me complain about a boxed version I had used. (I have yet to find a commercial vegetable stock that is remotely palatable.)
How to make vegetable stock
Our vegetable stock starts with a classic base of chopped up onion, carrot, celery, and fennel. You could also include parsnips, leeks, or corncobs, depending on what is season and available. We brown the vegetables in a little olive oil; you could also roast them in the oven for an even deeper flavor. It helps to brown the veggies first, so the stock gets infused with some of the flavors from caramelization. To achieve “umami”, that savory element that makes everything else taste better, we are including rehydrated dried mushrooms and a little tomato paste. Then we add water and garlic, bay leaves, rosemary, thyme, parsley, and peppercorns.
How long to cook vegetable stock
Unlike chicken or beef stock, which needs time to extract all the goodness from the bones, with vegetable stock, you cook the stock for only an hour to an hour and half. Less than an hour and there’s not enough time to extract the full essence of the vegetables. Beyond an hour and a half, the flavors begin to disintegrate. Given that there are so many vegetables, and they have a high moisture content, it may take more heat and longer time to brown than you would expect. Cook until the vegetables begin to brown. Set up a large bowl or pot with a sieve set over it. Line the sieve with a paper towel or coffee filter and pour the stock through it. When you have about half the stock poured through, stop, let what’s in the strainer filter through, and change the paper towel; the old one will be gunked up with debris. Filter the rest of the stock. Roasted Vegetable Stock - from The Kitchn Homemade Bouillon - from 101 Cookbooks