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Why do we salt the ice when making ice cream?

timothyrice.org

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Re: Why do we salt the ice when making ice cream?

#3

Always heard about this but never tried it. Sounds like fun. Great description, very clear and much better than just saying it lowers the temperature! Nice writing.

Author here, thank you!

It's been bouncing around in the back of my brain for a long time.

I couldn't find any clear and concise explanations about what really happens when salt is added to ice, so I did some research and wrote it out myself :D

Re: Why do we salt the ice when making ice cream?

#4

Always heard about this but never tried it. Sounds like fun. Great description, very clear and much better than just saying it lowers the temperature! Nice writing.

This is indeed a great explanation, and all the better for being both clear and concise.

Re: Why do we salt the ice when making ice cream?

#6
> It turns out, yes! What happens is that when the salt is added some of the ice melts – pulling heat from the system – until the temperature has reached the new, lower equilibrium point.

Correction, or addendum here: the actual dissolution of the salt is an endothermic process, so even if there was no ice, the temperature of water decreases when salt is dissolved.

Re: Why do we salt the ice when making ice cream?

#7
post #3

Always heard about this but never tried it. Sounds like fun. Great description, very clear and much better than just saying it lowers the temperature! Nice writing.

Author here, thank you! It's been bouncing around in the back of my brain for a long time. I couldn't find any clear and concise explanations about what really happens when salt is added to ice, so I did some research and wrote it out myself :D

More importantly, how was the ice cream you made? Apparently liquid nitrogen ice cream makes smaller crystals or something and tastes better? That could be the sequel…

Re: Why do we salt the ice when making ice cream?

#9
post #6

> It turns out, yes! What happens is that when the salt is added some of the ice melts – pulling heat from the system – until the temperature has reached the new, lower equilibrium point. Correction, or addendum here: the actual dissolution of the salt is an endothermic process, so even if there was no ice, the temperature of water decreases when salt is dissolved.

Presumably that is less significant a drop than the equilibrium melting freezing point being 5 degrees lower as even if endothermic it won’t be much will it and will just return back up when you add the warmer mixture bowl?

Re: Why do we salt the ice when making ice cream?

#10
post #3

Earlier quoted context omitted.

Author here, thank you! It's been bouncing around in the back of my brain for a long time. I couldn't find any clear and concise explanations about what really happens when salt is added to ice, so I did some research and wrote it out myself :D

More importantly, how was the ice cream you made? Apparently liquid nitrogen ice cream makes smaller crystals or something and tastes better? That could be the sequel…

> Apparently liquid nitrogen ice cream makes smaller crystals or something and tastes better?

It's about how fast you freeze the ice cream so the crystals don't grow.

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You can get N2 from a local gas supplier but a lot of grocery stores stock CO2 (Dry Ice) that can also be used for ice cream.

CO2 has the disadvantage of if you get it in the ice cream it makes it carbonated but the smoke looks like a witches cauldron so it looks cool imo.

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