Salt Questions · Home, wellness & DIY
Why do you put salt on ice when making ice cream?
Short answer
Salt lowers the freezing point of the ice, so the mixture of ice and salty meltwater becomes much colder than plain ice, well below 0 °C (32 °F). That extra cold pulls heat out of the cream fast enough to freeze it while it's churned. Old cookbooks used about 3 parts ice to 1 part coarse rock salt.
How cold does the ice bath get?
- 1Coldest possible ≈ −21 °C
- 2Ice + rock salt ≈ −10 °C or lower
- 3Ice and water 0 °C
How it works
Plain ice sitting in water can't get colder than 0 °C. Add salt, and the ice starts melting into brine, which can stay liquid at much lower temperatures. Melting absorbs heat from its surroundings, including the ice cream container, so the whole bath drops toward −10 °C or lower.
The classic ratio
Fannie Farmer's 1896 cookbook packed ice cream freezers with three parts crushed ice to one part coarse rock salt for smooth ice cream, and more salt for faster, coarser freezing. More salt means colder and faster, but faster freezing gives larger ice crystals.
Try it at home
Put a sealed bag of sweetened milk inside a larger bag with ice and a few handfuls of rock salt, and shake for 5–10 minutes.
Related on The Salt Almanac
More home, wellness & diy questions
- How do you clean a burnt pot bottom with salt?
- Can you use water softener salt for a swimming pool?
- Does salt water help clear up acne?
- What are the benefits of taking an Epsom salt bath?
- How do you use a salt rinse for a sore throat?
- Can salt kill weeds in a gravel driveway permanently?
Cite this page
For school projects and reports. Teachers often prefer the original sources too: see the list below.
The Salt Almanac. (2026, November 8). Why do you put salt on ice when making ice cream. https://saltalmanac.com/answers/why-do-you-put-salt-on-ice-when-making-ice-cream
“Why do you put salt on ice when making ice cream.” The Salt Almanac, 8 Nov. 2026, saltalmanac.com/answers/why-do-you-put-salt-on-ice-when-making-ice-cream. Accessed [today's date].
“Why do you put salt on ice when making ice cream.” The Salt Almanac. Last modified November 8, 2026. https://saltalmanac.com/answers/why-do-you-put-salt-on-ice-when-making-ice-cream.
Original sources
- Wikipedia. Freezing-point depression. https://en.wikipedia.org/wiki/Freezing-point_depression
- Wikipedia. Ice cream. https://en.wikipedia.org/wiki/Ice_cream