Before you go out and buy a bottle of Worcestershire sauce to dress up your recipes, you should know a few things. According to Delishably, Worcestershire sauce, while there are several variations and dozens of brands with specific recipes, is usually made from fermented anchovies, tamarind paste, molasses, onions, garlic, spices (determined by the maker), and vinegar — all of which then gets stored in wooden casks for eighteen months. Bon Appétit says that this peculiar blend of ingredients gives the sauce a deep flavor that’s used much like soy or fish sauce.
However, if you are vegan or vegetarian, you probably already noticed that anchovies, the small cured fish are on the list of ingredients. Luckily, there are some vegan and vegetarian Worcestershire sauce brands you can buy from, but generally speaking, the sauce is off-limits for non-meat eaters or those with fish allergies. Ditto for folks that eat Kosher. According to the Kosher Channel, Kosher law forbids mixing fish (which is in the sauce) and other meats (which the sauce usually dresses). While it’s feasible to eat Worcestershire sauce and stay Kosher, the site recommends simply going with a vegan alternative.
And last but not least in our ingredient-wary roundup are those who eat gluten-free. Many Worcestershire sauces use barley malt vinegar in their recipes, which means that if you’re sensitive or intolerant of gluten, you should only buy bottles labeled gluten-free (via Beyond Celiac).