Learn what happens to fish when you thaw and then refreeze it. Discover how this process damages the texture, often making it tough and rubbery.
1 Answer
Refreezing fish causes ice crystals to form and enlarge, damaging the cell structure and causing moisture loss, resulting in a rubbery texture when cooked. This is because the initial freezing process already damages the fish's cells to some extent.
Detailed Explanation:
When fish is frozen, water inside its cells turns into ice crystals. These crystals expand and pierce the cell walls, causing physical damage. The faster the freezing process, the smaller the ice crystals and the less damage. However, when fish is thawed, the damaged cells release moisture, leading to a drier texture. Refreezing exacerbates this problem. The existing ice crystals grow larger during the second freezing, causing even more cellular damage. When the fish is thawed again, even more moisture is lost. This repeated damage and moisture loss result in a tough, dry, and rubbery texture when the fish is cooked. The protein structure is also denatured, contributing to the undesirable texture.
Pro Tip:
To minimize texture changes, only thaw the amount of fish you intend to cook immediately. If you accidentally thaw too much, cook it and then store the cooked fish in the refrigerator for a day or two, rather than refreezing it.