What will the best type of ice to cool fish I catch and place in my icebox. Frozen plastic bottles of freshwater or saltwater? - assuming that they both start at the same temperature coming out of my freezer. My gut feeling is saltwater but I cannot figure out why. Will the fact that they are both encased and cannot melt into free space make a significant impact on their ability to chill the fish?
Fresh tap water - 1 tablespoon of salt per 1ltr of water
http://antoine.frostburg.edu/chem/se...icewater.shtml
Bit of info for you
Mythbusters did a thing ages ago on what ice is the coldest. I think the above formula is what they came up with
Salt water freezes at a lower temp ....... so you have a colder starting point -
If I was going out for a feed - I would freeze up 2 x 5kg blocks of salt water (half a cup of salt to 10lts of water) & add it to approx 10lts chilled salt water ........ you can add sea water in place of the chilled salt water when out on the water - but it wont last as long.
Chris
Freeze the salt water blocks at as low a temp as you can over as long as you can (7 days)
Give a man a fish & he will eat for a day !
Teach him how to fish
& he will sit in a boat - & drink beer all day!
TEAM MOJIKO
The best water to keep your fish in is the water you caught them in. If you throw crushed ice into this it will dilute the salt as it melts and this will result in your fish absorbing water through their gills. This could affect the quality of the fish. Using ice in containers so that it can cool your water but not mix with it is the better option by far. I have a block of ice in a plastic storage box which I put in my big cooler and then add a bucket of the water I'm fishing in. The water is chilled by the melting ice and the fish go straight into that. When I get home the plastic box (half melted) goes back in the freezer to freezee again for the next trip.
Adding salt to melting ice causes a reaction which lowers the temperature below freezing. It is possible ( but not practical) to get a temperature as low as -20 degrees celsius by doing this. (This property was used to make ice cream before the invention of refrigerators).
This does not help us with cooling fish however. If you make your own ice with salt in it and freeze it at home it will freeze at a lower temperature (if your freezer is good enough!), but it will come out of the freezer at the same temperature as ordinary ice - that is the temperature of your freezer. When it melts it will melt at a lower temperature than ordinary ice - therefore it will melt a bit sooner than ordinary ice as it takes heat from its surroundings.
But the main thing is that the cooling effect of ice comes from the fact that it takes a lot of heat to turn ice into water - this heat is called the latent heat of fusion - and for pure water it has a value of 80 calories per gram of water. This means that to turn 1 gram of ice at zero degrees into 1 gram of water at zero degrees requires 80 calories (or 332 joules) of heat. This is the same amount of heat that would be needed to heat 1 gram of water at zero degrees to a temperature of 80 degrees - so you can see that there's quite a lot of heat needed to melt the ice and that heat comes from the surroundings - meaning your fish.
Adding salt (or any other substance) to water lowers its freezing and melting point but does not alter the latent heat of fusion.
Sorry if this got a bit technical. Hope it helps!
Cheers Freeeedom
I feel so dumb
Google makes me look smart B)Originally Posted by FisHard
I feel so dumb
Is a few degrees really going to make any difference to the eating quality of the fish..... ???
I would be more inclined to look more into cooking method to get the best out your catch then the temperature of the ice...
Most people fish for a day maybe 2.. So as long as the fish is killed and bleed and put in a ice slurry say a 60L esky with 2 bags of ice with about 5L of salt water in a quality esky, its going to stay cold all day and when you get home there will be still heaps of ice in the slurry....
The only problem I find is getting the fish to go into the esky !!!
A few degrees will make no difference whatsoever.... an ice slurry in a good esky will keep the fish perfect till you get them back for cleaning.. its what ya do with them after that ..that will determine how they taste
dont knock on deaths door... ring the doorbell and run... death hates that!!
try packing 2 x 2litre coke bottles full of newspaper and 1 tablespoon of salt.a bit of food colouring for visuals if you like.i take 2 of these in my 70 litre esky and it does the trick.
i packed 1 1/2 sundays mails per bottle.
i have used these for 2 days at a time,brought them home and there still rock solid except for 2 cms around out edge,good cheap ice bricks,that stay frozen 4 times longer than any ice bricks i have brought before.
Softplasticsdude,
Mate, you've sold me. One (stupid) question: is it just the paper and salt-no water at all? Sounds like a ripper idea.
Cuzza
hi Cuzza,
you need to fill with water,but shred the paper and fill with as much paper as you can,trust me,it will take an hour per bottle,or in my case a 1 hour massage on my missus for 2 bottles done,she used a wooden spoon handle upside down to jam inside and keep compressing the paper,and a little water every now and then until full of paper and water and packed solid,it will then take 2 days to freeze solid.i got the idea from mythbusters when they built a paper mache boat,put a yamaha 4 stroke 100hp (or something similar) on the back and drove it for 20 minutes before it started to break up,they proved that paper and water together is much stronger than just water.
Just try to freeze your salt/fresh coke bottles/ice cream tubs/paper mache mixed containers for as long as possible before use. Deep frozen ice seems to last at lot longer than water that has only been frozen for a day or two. (We use 4L ice cream containers that sit in the freezer all the time and rotated - frozen for a few weeks before use) I thought frozen was frozen but results show different..
Also using previously boiled water seems to last longer too.. something about no air to break down the ice quicker?
Facinating stuff!
Gonna try it, including ther massage, dont know if I could last an hour tho.
"let not he boast who puts his armor on, as he who takes it off"
Thanks everyone, especially Freeeedom. So unless a chemical physicist comes along and tells us otherwise there is no difference as the latent heat of fusion is the same for both salt and fresh water. Both types of ice will melt at different temperatures but will still absorb equivalent amounts of heat. I know that making an ice slurry will chill your catch faster but in my case I don't do it for two reasons. One - here in the tropics the surface ocean temp is aroud 30 deg C and I don't want to waste my ice chilling the hot water. Two- I fish on a budget and have a hand me down fibreglass icebox(that I have refurbished); I don't want a lot of liquid in it because it will eventually find it's way into the insulation an wreck the box(hence the plastic bottles). Also I don't use a 60l icebox 'cause it's too SMALL.
Half your luck Goochi - I wish my 60 litre ice box was too small for what I usually catch!
Just a point about filling your Coke bottles with paper first. Because you are replacing some of the volume with paper (which does not melt) instead of water/ice (which does melt) you are actually reducing the amount of cooling that the frozen bottle can produce, since it's the melting of the ice that does most of the cooling. If you want to use Coke bottles I would use just water, but squeeze the bottle a bit before you screw the cap on so that as the water freezes and expands it doesn't blow the bottle apart.
Cheers Freeeedom
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