Salting the Ice?

[reim0027]

For those of us who are not fortunate enough to have a wort chiller, we use ice baths to chill our wort.

I've heard adding salt to the ice will drop the ice's temperature. Has anyone tried this, and is the effect worth it?

 

[aguy90]

no, salt lowers the freezing point of water. what this does is allow your ice to melt, allowing greater contact with whatever you put in it, without raising the temperature of the ice. this method is used in home icecream making.

 

[reim0027]

I see. But shouldn't the increased contact and the change in specific heat (water has a higher specific heat than ice) speed up the cooling?

 

[wilserbrewer]

The salt will lower the temperature of the cooling bath thereby speeding up the cooling effort. However, it will only speed up the cooling effort, and not cool a larger quantity. 10 lbs of ice will do the same amount of cooling w/ or w/out salt. Just faster w/ the salt. Same amount of ice is required, however overall cooling times may be reduced w/ the ice / salt mixture....my 2 cents!

ice and water...32 f
ice, salt and water...less than 32 f

 

[ajf]

Yes, it will speed up the cooling due to the greater contact area at a low temperature. It just doesn't reduce the ice's temperature. That's what aguy90 [edit] and wilserbrewer[/edit] said.

-a.

 

[reim0027]

Got it. I understood the comment about not lowering the ice's temperature (I could never figure out how salt did that; it was only what I've heard). But, it will speed up the cooling of the wort. My guess is the difference in chilling speed must not be that great, otherwise, more people would be doing it.

 

[Revvy]

I used to do it all the time before I got my chiller...

 

[NewBrew75]

I know from personal experience that it will cool down a room temp can of beer faster, so I'm guessing it would cool the wort faster. Don't know why I didn't think of it myself. Guess I'll be using salt from now on.

 

[wilserbrewer]

Yes, it will speed up the cooling due to the greater contact area at a low temperature. It just doesn't reduce the ice's temperature. That's what aguy90 [edit] and wilserbrewer[/edit] said.

-a.

Well I repeat:


ice and water...32 f
ice, salt and water...less than 32 f

Just actually tried it w/ a cup of crushed ice and water:

ice and water...33 f
added salt to ice and water...24f

of course the ice itself is still at 32 f but the solution drops in temperature. Try it?

 

[NewBrew75]

The freezing point of completely saturated saltwater(like almost 1/4 salt to water by weight) is about -4*F. That's quite a bit of salt though. But a can of norton table salt is $1.50 or so. So I guess that's up to you if its worth it.

 

[wilserbrewer]

Norton table salt...is that the Honeymooners edition...hah / jk

 

[BuffaloSabresBrewer]

Ive gotten an ice bath with rock salt down to -10. Add more salt.

 

[NewBrew75]

Norton table salt...is that the Honeymooners edition...hah / jk

Alright you got me. I'm sure rock salt would be much cheaper.