The Difference Between Fish Sauce and Oyster Sauce (and How to Use Them)

The food world has no shortage of potentially confusing terminology (and I’m not even talking about techniques where the French names happened to stick). Take, for example, fish sauce. The seasoning itself isn’t confusing at all, but find it next to a bottle of oyster sauce, and you might find yourself wondering, “What’s the difference?” Here’s a breakdown of what they are, and how you can use them.

When to use fish sauce

One of my favourite seasonings, fish sauce is a powerful umami elixir. This thin, reddish-brown liquid from southeast Asia is often used in tandem with other sauces and seasonings to boost the savoury flavour. It’s made by fermenting small fish, usually anchovies, in salt for a few months or up to two years. It’s salty, it’s funky, and a dab’ll do ya. However, there are a number of dishes, like som tum salad, that use fish sauce liberally.

You don’t need to cook fish sauce—you can mix it into salad dressings or drizzle it over rice—but it certainly can be added to dishes while cooking. Add a few drops to fried rice during the same stage you’d add soy sauce, mix some into your meatballs for depth and complexity, or add it to melted butter for a rich, savoury popcorn topping.

Here are a couple fish sauce brands I like:

• Squid Brand Fish Sauce
• Thai Kitchen Fish Sauce

When to use oyster sauce

It is my opinion that oyster sauce is the sauce you never knew you needed. When I first went away to college, I thought I could duplicate home cooking with barebones materials, like soy sauce and fish sauce, but I couldn’t nail the consistency. Oyster sauce was the missing component.

Oyster sauce originated in China and was originally made by boiling down oysters until a dark, complex sauce was achieved. (Although I particularly like this story that the first oyster sauce was made by a chef who forgot about a pot of oyster soup cooking away on the stove.) Modern, commercial oyster sauces are dark brown, use oyster extracts, and should be quite thick, often thickened with cornstarch. The resulting sauce is vastly different from the fish sauce mentioned above. It’s translucent, dark brown, sweet, deeply savoury, and a bit funky like an oyster, but not nearly as fishy as fish sauce. It should be thick enough that you could scoop it with a spoon.

To me, oyster sauce and fish sauce pair well because they complement each other with their differing traits. Oyster sauce adds viscosity to sauces like what you see in pad see ew, or pad kee mao, but equally as important is the sweetness. Oyster sauce has a savory, salty side, but it’s more like a sweet glaze that you can thin out to coat noodles or meat. Add it to marinades, stews, or sauces for stir fry at the same stage you’d add other seasonings.

Here are a couple oyster sauce brands I like:

• Mae Krua Oyster Sauce
• Lee Kum Kee Oyster Sauce

A good sauce can elevate any dish. Add a dash of fish sauce or a spoonful of oyster sauce to some of your veggie stir fries, chicken marinades, or beef dishes. Now that you know the differences between these sauces on paper, it’s time to explore them on the stove.