Rock Salt Substitutes for Ice Cream Makers, Salt Crusts and Seasoning

Need a rock salt substitute? First figure out which of two very different jobs it’s doing. If it’s chilling the outside of an ice cream canister, kosher salt or any coarse salt will do. If it touches the food, you need a food-grade salt, and the question is how much. Read the bag, too: in American stores, “rock salt” usually means a coarse salt sold for chilling ice cream makers or melting ice, and Morton says flat out that its Ice Cream Salt is not intended for consumption.¹

Quick answer

How the ratios on this page are labeled

• Computed: based on a measurable physical relationship.
• Attributed: a named source publishes this ratio. We quote it as theirs.
• Disputed: named sources give different answers to the same swap. You get each one, side by side.
• Method: our starting point, based on how the two compare. Taste and adjust.

First: is your rock salt food?

Read the bag. Morton describes its Ice Cream Salt as large rock salt crystals for ice cream makers and coolers, lists melting ice and snow among its uses, and says it’s not intended for consumption.¹ A bag labeled for ice cream makers, water softeners or ice melting belongs outside the canister, never in the food. Food-grade rock salt says so, or has a nutrition panel and is sold as a cooking salt. We found no regulator data on what non-food rock salt contains, so this is about labeling, not a claim that the stuff is harmful.

The substitutes below go the other way. They’re all food-grade salts, so they can handle the non-food job too.

If rock salt is chilling an ice cream maker

In an old-fashioned ice cream maker, or the “ice cream in a bag” kids make in classrooms, the salt goes into the ice around the container, not into the ice cream. Colorado State University Extension explains that salt lets the ice-and-salt mixture get colder than plain ice, cold enough to freeze the ice cream.² Morton says rock salt sprinkled over the ice in a cooler chills drinks faster, and colder, than ice alone.¹

1. Kosher salt

Ratio (Attributed): Colorado State’s ice cream in a bag calls for ½ cup of salt, “Kosher or rock salt,” with four cups of ice.² So it treats the two as interchangeable by volume. Use the same volume of kosher salt as the recipe or machine calls for in rock salt. Any brand works, since nobody eats this salt.

Kosher salt is much coarser than table salt,³ which makes it the closest stand-in for rock salt’s chunks. Morton credits rock salt’s large crystals with gradual cooling.¹

2. Table salt

Ratio (Method): Table salt is fine and dense. ATK weighs a teaspoon at about 6 grams, against 4.8 for Morton kosher salt and 2.8 for Diamond Crystal.⁴ So a cup of it holds more salt than a cup of kosher salt. Start with about half the volume of rock salt the recipe calls for, and add more if the mix isn’t firming up.

Rinse the outside of the bag or canister before you open it, so salty water doesn’t drip into the ice cream.

If rock salt is a crust or a roasting bed

Cooks sometimes bake whole fish, beets and potatoes under a crust of coarse salt, or roast oysters and clams on a bed of it. These are common kitchen uses, not tested claims.

1. Kosher salt

Ratio (Method): Use enough to cover, as the recipe says. The amount isn’t a seasoning measurement, because most of the crust gets thrown away. Kosher salt’s coarse grains make it the usual pick for crusts. Only food-grade salt belongs here, never ice cream salt.

2. Coarse sea salt or coarse Himalayan pink salt

These have the chunkiest grains of the food-grade salts most stores carry. Use them the same way, by the recipe’s volume.

If rock salt is coarse seasoning

Food-grade coarse rock salt goes into salt grinders, pasta water and spice rubs.

1. Coarse Himalayan pink salt

This one’s a rock salt itself. Morton sells a coarse grind for grinders, and its label gives 1.5 grams per ¼ teaspoon.⁵

Ratio (Method): In a grinder or for pasta water, season to taste.

2. Coarse sea salt

Coarse sea salt fills a grinder the same way. ATK notes that salt is sodium chloride whatever its source, and sea salts vary only slightly in flavor.⁶

Ratio (Method): Season to taste.

3. Kosher salt

Kosher salt is easy to pinch for rubs and pasta water. According to ATK, Morton’s kosher salt contains an anticaking agent, yellow prussiate of soda, and Diamond Crystal has none.⁷⁴

Ratio (Method): Season to taste.

If rock salt is measured into a recipe

By weight (Computed): Use the same weight of any food-grade salt. Codex requires at least 97% sodium chloride on a dry basis, from any source,⁸ so equal weights carry close to the same amount of salt.

By volume (Method): Start with less of a finer salt and taste. Large crystals put less salt in a spoon simply because fewer of them fit.⁹ For a teaspoon of coarse rock salt, start with about ½ teaspoon of table salt, the densest of the common salts at about 6 grams a teaspoon, or about ⅔ teaspoon of Morton kosher salt, which holds the same amount of salt by ATK’s weights.⁴

Not for pickling: home-canning guidance from the National Center for Home Food Preservation recommends canning or pickling salt.¹⁰ See pickling salt substitutes.

A note on flaky salts

Flaky finishing salts like Maldon are rock salt’s opposite: delicate where rock salt is hard. They’re a poor fit for crusts, grinders or ice cream makers, and a pricey one.

Notes for every swap

• Sodium. Table salt, kosher salt and most sea salts are about 40% sodium,⁹ and mined salt is the same compound. A swap only changes how much sodium a dish carries if it changes how much salt goes in.
• Additives and iodine. Table salt usually has an anticaking agent and is often iodized. Morton’s iodized table salt lists calcium silicate, dextrose and potassium iodide.¹¹ ATK’s tasters couldn’t taste a difference between iodized and noniodized salt.⁶

What isn’t known

• No regulator source we found establishes what non-food rock salt contains beyond salt.

Related

• Rock salt and cooking with rock salt
• Rock salt vs. sea salt and rock salt vs. table salt
• Kosher salt, Himalayan salt, cooking with Himalayan salt, sea salt and table salt
• Kosher salt substitutes, sea salt substitutes and pickling salt substitutes
• The best salt for cooking and too much salt

Footnotes

1. Morton Ice Cream Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³ ↩⁴

2. Ice Cream in a Bag: Changing Matter, Colorado State University Extension. garfield.extension.colostate.edu · Reference work ↩ ↩²

3. What’s the difference between kosher salt and other salt?, Tufts Health & Nutrition Letter, 2013 (updated 2019). nutritionletter.tufts.edu · Publication ↩

4. Kate Shannon Levine, The Best Kosher Salt, America’s Test Kitchen, 2019. americastestkitchen.com · Publication ↩ ↩² ↩³

5. Morton Coarse Himalayan Pink Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩

6. Salt Types and Measurements, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩²

7. Morton Kosher Salt Flakes, product page, Morton Salt. mortonsalt.com · Merchant ↩

8. Standard for Food Grade Salt, CXS 150-1985 (rev. 2012), Codex Alimentarius. services.bis.gov.in · Standard ↩

9. Sodium Sources: Where Does All That Sodium Come From?, American Heart Association, 2025. heart.org · Reference work ↩ ↩²

10. Salts Used in Pickling, National Center for Home Food Preservation. nchfp.uga.edu · Reference work ↩

11. Morton Iodized Table Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩