How To: Freshen Your Older Fish Filets with This Simple Trick

I love eating fish at restaurants—the flesh is flaky and tender; the scent, fresh and sweet. Cooking fish at home is a completely different story, though. Even when I do cook successful fish dishes, it often leaves this (for lack of a better description) fishy smell that permeates everything it touches. Monday's salmon becomes Wednesday's odor. It's enough to deter me from cooking fish, period.

The simple solution to this dilemma is using fresh fish, since the odor associated with fish usually comes from fish that's a little older. However, not all of us have the time or the resources to eat fresh fish. Don't worry—there's still a way to salvage your fish filets!

America's Test Kitchen has an ingenious solution that will not only remove the fishy smell, but also spruces up the flavor of that older fish: milk!

It may sound counterintuitive—not to mention a little gross—but it's true. Soak your filet in milk for 20 minutes, then pat dry and cook as you normally would for the recipe you prefer. The odor will be gone from the fish you're cooking, and the flesh of the fish will taste fresher as well.

Why Does This Work?

It all boils down to a chemical called trimethylamine oxide (TMAO), which is unique to sea creatures. Fish rely on TMAO to counterbalance the salty water around them; if their flesh didn't contain TMAO, the salt in the water would draw out the fluid contained inside of the fish via osmosis.

This is all well and good for the fish while alive, but as soon as the fish dies, bacteria and enzymes in the fish itself convert the chemical to trimethylamine (TMA)—the stinky chemical we associate with fishy smell.

The milk counteracts this smell with casein, a protein that promptly bonds to TMA and nullifies the scent. And since TMA is also responsible for the less-than-fresh, fishy flavor that normally accompanies older fish, giving your fish filets a milk bath also improves their flavor.

Some Helpful Reminders

While this easy method works for all kinds of fish filets, keep in mind that the fish still has to be edible for this hack to work. Remember this easy rule of thumb—"shiny, not slimy"—when looking at the flesh of the filet. In addition, make sure the fish feels firm under your touch. If the flesh gives way to your finger too easily, then you've held onto your fish too long and you've got to give it the ol' heave-ho.

Also, don't forget to pat the fish completely dry after its milk bath. The last thing you want after going through the trouble of freshening up your fish is for the lingering milk to alter the flavor of your dish!

Go Forth & Cook Without Fishy-Smell Fear

Whether your fish has been sitting in wax paper from the butcher's for a day or you're using a flash-frozen fish filet, soaking it in milk will banish that icky smell and flavor we all love to hate. And now that you know how to get rid of it, nothing stands in the way between you and your favorite fish dishes. So get to it! (But don't forget to let us know how it turned out, of course.)

Other Fishy Fish Hacks:

• 4 Innovative Ways to Cook (But Not Really Cook) Fish
• Make Perfectly Moist Fish with the No-Cook Poaching Method
• Isinglass (Or Why Your Guinness Has Fish in It)
• How to Cook Frozen Steak & Fish Without Defrosting Them First
• Sustainable Seafood: The Food Hacks Guide to Doing It Right