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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?

#101

Post by AngryData »

bobthepanda wrote: post #52
foobarian wrote: post #37

Earlier quoted context omitted.

I suppose I could store the salt water solution instead of throwing it away. Assuming I made ice cream often this would be acceptably frugal for me.

Also, if you really want to recover the salt, you’d just have to boil away the water. Alternatively, pickling is a perfectly good use of brine used for frugal purposes (extending the shelf life of produce, eggs, and what have you)

Boiling is quick and convenient, but just evaporating the water out with ambient air is all but free.

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

#102

Post by fuzzfactor »

timrice wrote: post #3
majikandy wrote: post #2

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

When you do the math or work it at the bench, the difference is quite remarkable in the number of kilos of ice needed (per kilo of ice cream) when starting with 0C ice versus -20C ice.

Hint: start with rock salt at -20C also.

Edit: and the prepared cream premixed and chilled to 0C.

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

#103

Post by AngryData »

HPsquared wrote: post #95
mensetmanusman wrote: post #63

Earlier quoted context omitted.

Without lead you get tin whiskers. I wonder how the math works out in terms of what’s better for the environment if electronics break a lot more often…

Given the explanation above, this now makes a lot more sense: if the (non-eutectic) solder has cooled gradually, some the higher melting component will freeze first at the coolest location, and things will move around, leaving less of the "low-melting" components in the remaining molten solder. Once it's all solidified, some areas will have more tin and other areas will have more of the other elements. This will indu…

I would also imagine the very quick solidification also prevents larger crystal formations. Crystal growth itself can also lead to separation of the metals and the extra few seconds or more of a half-liquid state solder could represent decades or more worth of crystal growth in ambient temperatures.

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

#104

Post by AngryData »

majikandy wrote: post #2

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.

You can quickly experience it yourself by holding an ice cube in each hand but pouring salt on one of them. While both cubes contain approximately the same deficit of energy, the salted one with the lower equilibrium temperature will pull heat out of your hand much faster and feel much colder. I guess you could always put it in two cups too.

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

#106

Post by simondotau »

lesuorac wrote: post #10
majikandy wrote: post #7

Earlier quoted context omitted.

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. -- 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 cauldro…

Surely there must be at least some flavours which could be compatible with carbonated ice cream. Cola ice cream, perhaps?

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

#107

Post by kimixa »

dcow wrote: post #62
fsckboy wrote: post #31

Earlier quoted context omitted.

it's not just the coldness of the ice, salt dissolving in water actually decreases the temperature, it's an endothermic reaction. the salt dissolving into the water brings the water down to 0... omg time for Farenheit to shine... brings the water down to 0F without freezing it (because of the lower equilibrium temp), which is -17.8C (Farenheit uses this endothermic salted water temp as its definition of 0, I think be…

I understand Fahrenheit now.

Unfortunately for this theory, brine freezes around -6f

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

#108

Post by aeternum »

kimixa wrote: post #107
dcow wrote: post #62

Earlier quoted context omitted.

I understand Fahrenheit now.

Unfortunately for this theory, brine freezes around -6f

You need something colder than brine to freeze brine. Fahrenheit didn't have that so the theory/story is still plausible.

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

#109

Post by zwieback »

wwweston wrote: post #68
zwieback wrote: post #15

Earlier quoted context omitted.

Right, alcohol, sugar and salt all change the hardness of the ice cream but you can only add so much until the flavor isn't what you want anymore. I don't think the ice cream texture is due to the melting point, though, that the post talks about, it's also whether large enough ice crystals can form. It feels like cheating but adding stabilizers (gums, mostly) was really a game changer for our homemade ice cream.

Which texture hacks have you played with besides xanthan gum?

In addition to the ones mentioned above we've also tried powdered milk (cribbed from Salt&Straw, a local favorite) and this thing called "Avacream Ice Cream Stabilizer". That product works great as well but not sure I can really tell the difference, maybe the xanthan/dried milk is a little less smooth.

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

#110

Post by DIARRHEA_xd »

AngryData wrote: post #104
majikandy wrote: post #2

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.

You can quickly experience it yourself by holding an ice cube in each hand but pouring salt on one of them. While both cubes contain approximately the same deficit of energy, the salted one with the lower equilibrium temperature will pull heat out of your hand much faster and feel much colder. I guess you could always put it in two cups too.

Almost. For the salted cube, remember to pour the salt on your hand and then put the ice cube on top.
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