How Long are fish good in an esky for??

[Schulzy]

Get your party ice in advance and freeze it as long as possible and use block ice as well fish should last a week wouldn't worry about gutting lets to much moisture into the fish and stack them up

[Muddy Toes]

Dale, I make salt water blocks. Go to Super Cheap and buy the the SCA 10 litre basins for $5. I dissolve two table spoons of salt and mix with fresh water then freeze. I have quite a big esky at about 400 litres. If going out for a couple of nights I take five or six of the salty blocks and about 80kg of party ice. Fortunately for me I've had access to a free supply of party ice for the last six years. All our fish are bled in the kill tank which ensures the slurry stays clean then they go into the esky. As soon as we start putting fish in the esky I start pumping in sea water. I keep adding sea water as the fish go in to ensure they remain covered.

This system works very well. Water temp up here can be close on 30c in the summer hence the large amount of party ice. The slurry is so cold that it hurts like buggary digging the fish out. A couple of years ago I checked the temp at the top of the esky with an infra-red after a three day trip - it was -8c!

Regards,
Dave.

Why don't we get salt ice over here?
It's pretty damn popular in New Zealand but I've never seen it for sale here, the stuff freezes below 0degC!!!!

[Noelm]

I make my own salt water ice too, not too sure it is all that much better than normal fresh water ice, but it does keep the salt water slurry salty.

[WalrusLike]

Guys experience beats guesses every time. So I will happily bow to your experience of salt water blocks.

But I must say I am surprised..... The physics doesn't seem to add up. Adding salt to 3 or 4% like seawater will lower the freezing point to about -2 degrees. But it doesn't increase the ability to absorb heat without raising temperature.

In fact the reverse. It takes less heat to raise its temperature.

I see that salt water slurry is best because it stops the osmotic swelling of the fish, but in terms of keeping colder I can't see how it could....


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[thrillseeker1]

Interesting subject.
There is not much point freezing sea water because the main component of that ice is pure water. The salt will form pockets of brine(salty liquid) in the ice. In fact sea ice is used for drinking water in some places in the world.
The trick with brine is, by increasing its salinity(right up to a saturated solution) it can be kept as a liquid right down to -21 degrees celsius.
Just add salt water(3-5% NaCl) with fresh water ice, the fresh water(from the salt water) freezes out, the brine becomes more concentrated and stays liquid and drops below 0 C, or add salt granules to reduce the brine to well below freezing if needed. Fresh water in ice is still only +1C anyway.
It's the same principle that melts ice on roads, increase the salt concentration, the ice will melt, so long as the ice temp doesn't get below -21 C