Almost anytime you order seafood at a restaurant, whether it’s lobster tails or salmon steaks or fish tacos, you are going to see lemon slices. The lemon wedges are often placed to the side, lying in wait for you to squeeze them over your fish. Other times, lemon juice is worked into the sauce that is already in the dish, like lemon garlic butter sauce on shrimp. Where does this combo come from, and why is it so commonplace? For some expert answers, Chowhound spoke exclusively with Curt Brown, a lobsterman and marine biologist at Ready Seafood in Maine and a board member of the Maine Lobster Marketing Collaborative.
According to Brown, who specializes in lobster dishes, it all comes down to the acidity: “The acidity of the lemon makes the sweetness of a lobster pop. Citrus notes, like lemon, are a great complement that brighten the flavor and balance the richness of the meat.” Citrus fruits like lemons also play an important role in disguising fishy tastes in seafood, such as salmon. With shellfish like lobster, which can taste fairly sweet, the sourness of a dash of lemon juice adds some complexity because opposite flavors like sweet and sour blend well. It’s similar to how lemons can balance overly sweet drinks. For an extra bright, citrus-like flavor, Brown recommends combining lemon and dill together to pair with lobster.
The chemistry between lemons and fish
Scientifically speaking, the reason for lemon’s natural pairing with seafood involves a chemical compound called trimethylamine. This compound is found in the muscle tissues of lots of marine species, and it is directly responsible for the strong, acrid “fishy” smell in most fish. When the fish is alive, a version called trimethylamine N-oxide helps it regulate the saltwater constantly entering its body (both the water pressure and its saltiness). When the fish dies, the compound undergoes a chemical reaction and begins giving off that famously pungent smell. Trimethylamine is also a weak base (it has a pH level above seven), and if you remember your chemistry, it can be neutralized by an acid like lemon juice. Thus, a squirt of lemon juice clears up that seafood odor.
Returning to the flavors, what else can you do to punch up that sweet and sour combination of sharp citrus and briny seafood? Curt Brown says you can bring in even more flavors like tang and spiciness to create complex flavors. As an example, Brown mentions a “bang-bang” sauce he likes to make. “I use mayo and sweet Thai chili sauce 1:1 with some sriracha and honey,” he notes. “[It] adds a nice little kick but doesn’t overwhelm the lobster.” Additionally, Brown recommends a lobster or scallop flambé in Pernod liquor with heavy cream. When it comes to added flavors, lemons and seafood are quite versatile.
