Freezing fish fillets for the obsessive-compulsive angler

I'm thinking about putting a small fan in the chest freezer and putting fish on wire rack to speed freezing.
Now I just need to catch more fish! =)

I'm sure someone here can do the thermodynamics analysis of using airflow vs. liquid conduction ...  anyone?

-Allen

I'm thinking about putting a small fan in the chest freezer and putting fish on wire rack to speed freezing.
Now I just need to catch more fish! =)

I'm sure someone here can do the thermodynamics analysis of using airflow vs. liquid conduction ...  anyone?

-Allen

=) I see a freeze off coming!

I'm thinking about putting a small fan in the chest freezer and putting fish on wire rack to speed freezing.
Now I just need to catch more fish! =)

I'm sure someone here can do the thermodynamics analysis of using airflow vs. liquid conduction ...  anyone?

-Allen

At 0deg C, air has a thermal conductivity of 0.0243 W/mK.  50ppm saline solution at 0C has a thermal conductivity of 0.563W/mK.  So the saline solution has about 20x the thermal conductivity of air.  I struggled with Thermogoddamnics in undergrad, so beyond that data I won't comment. 

I love frozen saltwater.  I freeze bags of it then throw it in my cooler.  Keeps beer and other less necessary food items colder longer. Granted, it is not as highly concentrated as what Polepole describes. Unfortunately, the first time I used a bag in my catch cooler I didn't realize how cold it really was going to keep the fish.  At the end of the day I had a partially frozen coho.

Fully saturated salt water has a freezing point of -6 degree F. I think it will still be liquid in most home freezers.

SumpNZ ... of course it's not just the thermal conductivity we care about.  It's also the  heat capacity / specific heat, right?  Come on, dig into the deep recesses of your nerdity and enlighten us!   

-Allen

Fully saturated salt water has a freezing point of -6 degree F. I think it will still be liquid in most home freezers.

SumpNZ ... of course it's not just the thermal conductivity we care about.  It's also the  heat capacity / specific heat, right?  Come on, dig into the deep recesses of your nerdity and enlighten us!   

-Allen

Ok, I'll dig a bit.  But only because I know it turns you on.   

Interesting discussion. Good stuff.

Question for those who have had sealing issues with your food savers (or other vac sealers)... Are you pulling the pinbones from your filets before freezing? If you don't pull the pinbones, it can lead to little pinholes in your bag. Not so much because the bone itself pokes out through the bag.... but because the little pointy raised area on the outside of the bag where each pinbone sticks up a little will rub and knock against other rock solid frozen things in the freezer when you dig around for some dinner.

Question for those who have had sealing issues with your food savers (or other vac sealers)... Are you pulling the pinbones from your filets before freezing? If you don't pull the pinbones, it can lead to little pinholes in your bag. Not so much because the bone itself pokes out through the bag.... but because the little pointy raised area on the outside of the bag where each pinbone sticks up a little will rub and knock against other rock solid frozen things in the freezer when you dig around for some dinner.

I've had problems with the pin bones in smoked fish poking holes in vacuum bags.  So when I vacuum pack smoked fish fillets, I run the back of a spoon over the line of protruding pin bones to bend over and flatten the bones.  This prevents punctures.  You could do the same thing before you vacuum pack frozen fish fillets.  I cut the pin bones out of un-frozen fillets.

I ended up springing for one of those fancy little pin bone tools from a high-end kitchen supply store. It cost me about $30, but it works great and should last forever. Now I just pluck out all pinbones when I filet.

Fully saturated salt water has a freezing point of -6 degree F. I think it will still be liquid in most home freezers.

SumpNZ ... of course it's not just the thermal conductivity we care about.  It's also the  heat capacity / specific heat, right?  Come on, dig into the deep recesses of your nerdity and enlighten us!   [emoji14]

-Allen

There are way too many variables here....

Volume of water
Volume of fish
Volume of air
Starting temp of fish

The biggest question mark is in regards to agitation. To what level does moving air disperse heat compared to non moving water ....

We have a fish wheel and finally invested in a mini pack 45 XII a couple years ago before that I always wrapped fish the way we did growing up.  A layer of Saran wrap two layers of newsprint and the heavy waxed butcher paper.

Combine the old method with having to do a couple hundred sockeye and a half dozen kings or so a day and the price of nice vacuum packer was worth it.

The time and  effort required to harvest plus the value of the resource in fish we harvest makes taking care of it all the more important

Fully saturated salt water has a freezing point of -6 degree F. I think it will still be liquid in most home freezers.

SumpNZ ... of course it's not just the thermal conductivity we care about.  It's also the  heat capacity / specific heat, right?  Come on, dig into the deep recesses of your nerdity and enlighten us!   [emoji14]

-Allen

There are way too many variables here....

Volume of water
Volume of fish
Volume of air
Starting temp of fish

The biggest question mark is in regards to agitation. To what level does moving air disperse heat compared to non moving water ....

All of which can be factored into the analysis.  The same variables affect your scenario as well, so we can state the assumptions and do an A/B comparison.

-Allen

I'm not a math or engineering wizard.  But here's a simple experiment I could perform to compare how fast fish fillets freeze in the air with how fast they freeze in a chilled super-saturated salt solution.  I would make a tub of super-saturated salt solution and let it get to freezer temperature.  Hopefully it would remain liquid, or at least slushy.  Then I would vacuum pack a bunch of similar-sized fish fillets.  I would dump half of the fillets in the salt solution, and put the other half of the fillets on racks in the freezer.  Then every ten minutes I would open the freezer for a moment and poke the fillets with my finger, to see when the fillets froze stiff.

A more accurate way of performing this experiment would be by using thermometer probes.  I have two digital thermometers with temperature probes on wires which I use to monitor the temperature of a water bath and the internal temperature of sausages in that water bath.  I could put probes into the center of two fairly thick fillets and run the wires out through the gasket in the door of the freezer.  Then I could write down the internal temperatures of the fillets every ten minutes.  But I need to check that my remote thermometers go down to zero degrees Fahrenheit or below.

I don't have room in my freezer for a fan and a lot of air circulation.  It's full of various tasty items.  So I wouldn't be able to test the effect of rapid air circulation on freezing speed.

I vac pac them pat them dry first

I vac pac them pat them dry first

Nice chamber machine!