Quote:
Originally Posted by -scallywag-
FREEZING FISH:
I'm pretty sure they (commercial ships) flash freeze the fish to a super low temperature to minimize the amount of sublimation (freezer burn or de-hydration) that occurs, after that the fish are stored and transported in a "normal" freezer where they very slowly warm back up to just below freezing, which could take weeks. As long as the fish in the freezer are colder than the freezer itself sublimation, generally will not occur. Basically the opposite of freeze-drying. So from a scientific stand point I think that vacuum sealing/freezing is still the best way for us, but after reading Jims post I think vacuum sealing/freezing the whole fish would be even better, or more practical, in big chunks with the skin on.
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With a little advanced preparation and a little money you can easily come up with a close approximation of how they freeze fish on commercial vessels. The advanced preparation is buying dry ice and pre-chilling a cooler before you go fishing. It helps to have the dry ice in the cooler for at least several hours so that the interior of the cooler has been brought down as close to the dry ice temperature as it is going to get. This is also the expensive step. Dry ice is generally about $1/lb and you will probably need 10-20lbs. This works out OK if you know you are going to catch fish, but if you are like me, it could be a waste of money when you don't catch anything. When you get your catch ashore, you should remove the head and tail and gut it. Wrapping in butcher paper would help protect it as well. Just open the cooler long enough to slide the fish in. Once the fish is in the cooler, don't touch it or open the cooler for at least 12 hours. By then it should be rock-hard. If you plan on keeping it frozen for a while, you might want to bag and vacuum seal it before you transfer it to the freezer.
The advantage of the dry ice is that it freezes the fish much more rapidly than a regular home freezer. Evidently, rapid freezing results in smaller ice crystals, which do less damage to cell walls. This will give you a much better texture when thawed. I have done this a few times with YT and halibut and it seems to work very well. Freezing will also kill those nasty parasites, so you can use the fish for sashimi after thawing (even salmon and halibut).
BTW:This is also an excellent way to freeze delicate fruits like strawberry, blackberry and raspberry.