How to: Defrost your seafood

Best practice

At Royal Greenland, we recommend slow thawing in the refrigerator to preserve the flavour and texture in the best possible manner:

Place your fish or shellfish on a rack or tray, where the excess water from the protective glaze can drain (it is key that the water is able to drain, so be sure not to thaw your seafood in a bag or container). Place the tray in the refrigerator at 2°C until the seafood is fully defrosted (depending on the size of the single fish/shellfish and portion). Once the seafood is defrosted, you can store it for up to 24 hours at 2° C on the tray. If you are challenged by keeping the temperature at 2° C at all times, we recommend storing the fish on ice in the refrigerator.

Why is it so important to freeze fast and thaw slow?

When you select how to defrost your seafood, you are not only dealing with food safety issues but also potentially huge impacts on the meat structure and flavour of the seafood.

Thawing seafood rapidly is in general not a recommendable method as the drastic temperature change can affect the cell structure, potentially causing the seafood to turn out mushy and flavourless.

A slow thawing will ensure that your fish or shellfish shed as little water as possible and thereby preserve the delicate cell structure of the fish in the best possible manner. With this method, you will obtain a moist and juicy fish packed with flavour. It requires planning and a little patience, but we promise you, it is worth the wait!

But can I…

There is no disputing that the above is by far the absolute best method for defrosting seafood, but it is not exactly fast. There are of course other methods than the one mentioned above, so let us explore some of these and how they affect the produce:

…thaw seafood in running cold water?

This may be the second best option and it is faster than thawing in the refrigerator, as waters' heat-conducting ability is 8 times quicker than air. Place a large bowl in your sink and put the seafood directly in the water. Avoid thawing it in a bag, as the excess water will be unable to drain from the seafood. Make sure the seafood is fully submerged during the thawing and that you have a steady flow to avoid the water becomes warm. Monitor the process carefully.

Be aware that this method for defrosting may cause your product to loose moisture and texture. Because the flavour of seafood is highly affected by the salty seawater and salt is water soluble, a long bath directly in the cold, running water can be a detriment to flavour. Be sure to use water at 2°C or lower to be able to store the seafood afterwards for up to 24 hours. If the water temperature is higher, use the seafood immediately after.

We do not recommend this method for Greenland halibut as the meat structure is more delicate than other whitefish. This process is also not well suited for cold-water prawns, as the protective glaze is likely to form a bulk of ice and create an uneven thawing process.

…thaw seafood in lukewarm water?

If you are in a hurry then this method will surely do the trick. However, there are some other factors that you compromise: You must use the seafood immediately after it is thawed because of the possible bacteria development – lukewarm water can be a house party for bacteria. The rapid temperature change will also cause the seafood to lose more water, than if it was thawed at a lower temperature. This can cause the seafood to appear dry, mushy and dull when cooked.

…thaw in the microwave?

Be careful if you choose to defrost in the microwave, this is not a method we would recommend. Because of the uneven heating in the microwave, parts of the seafood may still be frozen or even overheat and start the cooking process, resulting in a likewise unevenly prepared fish or shellfish when you cook it. Use the seafood immediately after thawing.

…cook the seafood straight from the freezer?

You can cook natural fish and shellfish straight from the freezer, but it is a poor idea for retaining flavour and moisture. Once the frozen fish hits the scorching surface of the pan, the fish will shed a much higher amount of water compared to a properly defrosted fish because of the rapid temperature change and is far more likely to turn out dry and dull. If you choose to cook the seafood directly from the freezer, whitefish fillets tend to deliver the best results if you apply a gentle cooking method (e.g. sous-vide).

With convenience products, such as breaded or battered fish, the seafood is designed to cope with the rapid temperature change and the delicate seafood is somewhat protected by the breading. In this case, seafood can be well suited for cooking in the oven or the deep fryer straight from the freezer.

…refreeze thawed seafood?

It is possible to refreeze seafood, but be aware of the change in quality. For each time you freeze seafood, the amount of ruptured cells increase, causing the seafood to gradually loose more moisture and become more dry for each time. If you must refreeze, we recommend applying a protective water glaze on your seafood to avoid freezer burn, placing it on an already frozen metal tray and freezing it as fast as possible. We do not recommend refreezing cold-water prawns.