9 Secrets for Vacuum-Sealing Your Fish

Let’s face it: Vacuum-sealing fish involves more steps and time than simply dropping your fillets in a plastic bag and setting into your freezer. No argument there. Also, however, no arguing with the fact that you can face freezer-burned meat with a strong fishy taste when you decide to cook it for dinner a few months down the road — or you can thaw out fillets that look, smell and taste as good as the day they were caught. Here’s some insight to ensure that result.

What is vacuum sealing?

A vacuum sealer removes air and moisture from a plastic bag containing fish, typically a fillet — or with small fish two or more fillets; for large fish, a piece of one fillet — then seals the plastic tightly by thermally bonding it at the opening.

Is it really worth the hassle?

Only if you want your frozen fish to taste as good as the day you caught it. Moisture leads to decay in flesh, even when frozen solid. The removal of moisture and air from a bag with fillets, and sealed tightly, ensure long freezer life. It’s reasonable to expect a freezer life for vacuum-sealed fish, with little or no loss in quality, of one to two years. No more inevitable spots of freezer burn on fillets, no fishy- or off-taste from fillets exposed to air.

1. Use a purpose-built vacuum sealer

High moisture content in fish flesh may require the sealer to remove excess moisture. Chamber sealers may do a better job of this, but are pricier. Some less expensive (and more widely available) external sealers offer a setting for moist foods — such as fish fillets. One recent review in New York online considers several models of vacuum sealers.

2. Keep the bag dry

Make sure the end of the bag to be sealed is completely dry to ensure a good seal (some use paper towels to ensure the upper 2 to 3 inches of the bag, below the seal, are dry), and watch that no part of the fillet ends up in this area that would get in the way when sealing. Also keep an eye on these upper two inches or so when sealing to be sure no liquid works its way up the bag before it’s sealed.

3. Pre-freeze your fillets

Lacking a sealer designed to remove moisture, “pre-freeze” by setting bags in freezer long enough for fillets to get firm (a couple of hours or so) and then vacuum-seal the package. Some wrap fillets in plastic wrap, then partially freeze them before vacuum sealing.

4. Consider soaking fillets in brine before sealing

Even a few minutes in a brine solution before you pat the fillets dry will help keep the flesh firm.

5. Thoroughly dry fillets with paper towels

Don’t make mistake of just a quick pat; the more moisture you can remove, the better the result will be.

6. Check for bones

Check carefully for any bones, particularly rib bones, which were cut off but could still protrude from the fillet to pierce a sealed bag. Make sure you can find/feel no bones protruding from the fillet.

7. Season fish if you wish before sealing

This is a great time add any spices you might want. Some like to put their fillets in marinade in the bag to be vacuum sealed, but lacking an expensive chamber sealer, it’s best to pre-freeze fish with marinade before vacuum sealing. Another method calls for placing each fillet in a Ziploc bag with marinade, zipping it shut, and then vacuum sealing that.

8. Avoid overfilling bags to be sealed

Less in each bag is generally preferable.

9. Thaw slowly

Not on a kitchen counter but in the refrigerator (this typically requires you to start thawing a day before intended use). While it’s thawing, remove fish from the bag entirely, putting it into a bowl or onto a plate: Clostridium botulinum bacteria might have set up shop in the anaerobic conditions inside a vacuum-sealed bag. Removing it and exposing it to air will ensure that botulina spores won’t bloom on your fish. (Spores can’t develop in temperatures under 38 degrees F even in the bag, but some home refrigerators may be set warmer than this.)

So bottom line! If you know you can't consume all your fish within the first few days, the investment of a vacuum sealer is invaluable to ensure you have the freshest fish MONTHS down the line.