The difference between broth and stock is a subtle one, and even chefs often use the two words interchangeably. But there are distinctions between these words; here are some ways you may want to keep them separate.
Think of stock as a “building block” (stock and block rhyme, which helps) in a recipe, whether for a soup, gravy, or sauce. In many recipes for stock, meat or vegetables (or both) are roasted before being simmered in liquid, adding additional layers of flavor that will enhance whatever dish the stock will be used in. The point is that a stock is something that is prepared (or reserved from cooking another recipe) for the purpose of serving as a basis for something else.
Broth, on the other hand, can refer to something much simpler. Boiling hot dogs in water, for example, is enough to produce a broth. While you could use that hot dog broth as a stock for another recipe, most people just consider it a byproduct of cooking the hot dogs. You might sip the broth of a soup (it’s part of the finished product), but you would not typically sip the stock of a soup (it’s one of the ingredients).
Sample sentences:
The picky child pushed the vegetables in her soup aside, preferring to sip the broth instead.
The chef strained the stock of its lobster shells and veggies for use in the next day’s chowder.
Another way to tell the difference between broth and stock is to consider two different recipes for chicken soup: 1. Vegetables, chicken, rice, and seasonings are covered with water and maybe a squeeze of lemon juice and simmered until done. The resulting liquid of the soup is referred to as its broth. 2. The same ingredients are simmered in stock made the day before by boiling the bones of a roast chicken with herbs and mushrooms. The resulting liquid as enjoyed in the finished soup is still referred to as the soup’s broth.
Now what about those prepackaged cartons of stock and broth on the grocery shelf—is there any difference? Well, as both are prepared for use as a cooking base, we would call both of them stock. However, products labeled stock tend to have (depending on the brand) slightly richer, fuller flavors than those labeled broth.