Everything you need to know about your go-to cooking liquids.
For many home cooks (myself included), stock and broth are considered virtually the same thing when it comes to adding a cooking liquid to a recipe that calls for either/or. When shopping, I normally pick up a box or can of the liquid according to whichever I see first—not paying much attention to the label or thinking that there was a significant difference between the the two. While they are completely interchangeable in most recipe contexts, there is technically a difference in the way that stock and broth are made and used.
What is stock?
The culinary purpose of a stock is to help build flavor and act as the base usually for (but not limited to) gravies, soups, sauces, stews, and glazes. Stock is made by simmering meat bones, typically from chicken, beef, or veal, with a vegetable mix of carrots, onions, and celery (also known as a mirepoix) in a large pot of water. The bones are often roasted prior to being simmered for an additional depth of flavor; however, this step is not required. The simmering time varies depending on the variety of bones being used; chicken bones tend to simmer for a few hours, while beef bones can simmer for up to 8 hours or overnight. While the stock is simmering, the collagen present in the bones seeps out, giving the stock a thick body, rich flavor, and gelatinous texture when cooled. Stock is traditionally unsalted and unseasoned. Therefore, it’s not considered a stand-alone ingredient.
In professional kitchens, stock is likely made in-house because it's used in a myriad of dishes. In restaurant kitchens and in culinary training, the line between stock and broth is more distinctly defined. The key differentiating factor comes down to the ability to define and develop the flavor profile for each individual dish that utilizes the same batch of stock. This is why it's best to under-season a batch of stock. This allows you to control and build flavor with the addition of other ingredients in the dish, such as aromatics and alliums, and control the salt level as needed.
What is broth?
Broth is prepared in a similar manner to stock with the major differences being that broth has a much shorter cooking time and is more heavily seasoned—idea being, it could be consumed as is. Broth can made using both the bones and meat of an animal (unless it’s a vegetarian broth), along with herbs and a mirepoix. Broth typically has a thinner consistency than stock because the bones’ collagen is not fully drawn out given the shorter cook time of about 3 hours start to finish. By definition, broth doesn’t need further dressing up and seasoning and it will contribute the flavors it has been infused with to whatever dish it’s incorporated into.
You can easily turn stock into a rich broth by adding additional seasonings and, of course, salt. As mentioned above, at home, stock and broth can be used interchangeably when preparing recipes that call for one or the other. The key component that you should consider addressing when purchasing prepared stock or broth is the sodium content—as this can impact how much salt you ultimately want to add during cooking. Even though stock traditionally does not include salt, store-bought versions for both stock and broth typically contain relatively high amounts. To maintain the most control over the flavor of your recipe, opt for the low-sodium or unsalted options.
What can I substitute if I don’t have either?
In my experience, when I’ve had neither stock nor broth on hand, plain ol’ water is the next best thing. I simply overcompensate a bit for flavor by amping up my seasoning and aromatic elements, as well as adding a pinch more salt. As long as you’re mindful of this, water can be used in place of stock or broth for a perfectly flavorful soup base, poaching liquid, and even for deglazing a pan.