By Wade Truong. Photo by Wade Truong
When done carefully, freezing fish can help preserve a day’s catch for meals in the future. Fish is a more delicate protein and requires a little more attention when being prepared for long-term cold storage. Things to consider when freezing fish include:
Types of fish: Some fish freeze better than others. Dense and firm-fleshed fish (like rockfish, cobia, or mahi) hold up well frozen. Softer fleshed fish, particularly fatty and oily ones (like bluefish or Spanish mackerel) do not freeze well, and should be eaten fresh. Salmon and tuna have high amounts of fat, so they freeze okay, but they are much better fresh. Commercial freezing equipment is vastly different from home-use products, so just because a fish is sold frozen at the grocery store doesn’t mean it can be frozen well at home. The incredibly fast and cold freeze commercial process is difficult to replicate in the home kitchen.
How to freeze: I grew up seeing fish frozen into milk jug blocks of ice, with their tails sticking out of the top. This method—surrounding the fish with water before freezing—is not a bad one, but the same results can be achieved with a vacuum sealer, and you’ll save a ton of space. The key is to reduce the amount of oxygen the fish will be exposed to. With less oxygen, there is less oxidation and breakdown of the fish. The water method works because it displaces the oxygen, just like a vacuum sealer.
Skin on or off: The less a fish is broken down, the less surface area it has, which leads to less oxidation. Leaving the skin on a fish protects that side of the fillet from being exposed to any oxygen. This does come with minor issues though. The skin and the lateral line are where the fat is concentrated. This concentration of fat is where most of the “fishy” or strong flavors come from. You can remove the skin and lateral line before freezing, or leave it on and trim after you thaw. If freezing a whole fish, I leave the skin on. With fillets, I usually skin them. After thawing I trim the outermost layer off the fillet if it has any strong smell.
Bones: Fish bones are often needle-like and like to punch holes in vacuum bags and sealed plastic bags. The best way to prevent this is to remove or trim down bones if they are protruding, and wrap them with a layer of paper or plastic to keep them horizontal to the sides of the bag or add a layer thick enough to resist puncturing. If I’m vacuum sealing a fish and the gill plate or dorsal fin pokes a hole in the bag, I trim the bag down to fit inside another bag and seal it again. Parchment paper, wax paper, or foam plates all work well to keep bags from being pierced.
Thawing: Regardless of how you freeze fish, you should thaw it roughly the same way. If they are sealed in a bag, the bag should be cut before thawing. Fish should be thawed slowly and kept at a safe, refrigerated temperature. This is for both quality and safety. Fish spoils at cooler temperatures and faster than most other meats. It also thaws faster than denser proteins. The night before I plan on cooking it, I pull the fish from the freezer and put it in the fridge. Thawing frozen fish under cold running water works as well and is a little faster, but make sure the water is cold. Whatever you do, do not thaw frozen fish in a microwave oven.