Kosher salt is slightly different to regular table salt in that it is made from larger and coarser grains that are often uneven in size. It also contains no iodine additives making it the salt of choice in many kitchens.
While you likely know regular salt can be used to melt ice you might also want to know whether or not you can use kosher salt to melt ice just as easily and if it differs from regular salt in how it melts ice.
Kosher salt is effective at melting ice, just like regular salt. It won’t melt ice quite as quickly as finer salts like table salt because of its larger and coarser grain size which gives it less surface area. However, this difference is small kosher salt is still very effective at melting ice.
In fact, Kosher salt can be extremely effective at melting ice on driveways and roads because the larger grain size makes it easier to spread over a larger distance compared to finer kitchen salt. However, you do need to be careful as salt can deteriorate concrete driveways and cause it to flake and break apart.
Whether the salt is for your front driveway or for defrosting your frosted freezer, enough of the right salt will do the trick to melt the ice away.
When salt mixes with water it lowers the freezing temperature of the mixture causing the ice to melt at a lower temperature than it would otherwise.
Salt, including kosher salt, can also prevent future snow and ice build-up. Keep reading below to find out everything you need to know about Kosher salt, its properties, and how effective kosher salt is at melting ice.
Can You Use Kosher Salt To Melt Ice On Your Driveway?
Kosher salt will be effective at melting ice on your driveway from 0 to -18ºC (32-0ºF) however you need to be careful about what types of driveways you use kosher salt on. It is NOT advised to use kosher salt (or any salt) on concrete driveways as this can cause damage to the concrete ruining your driveway.
Asphalt driveways are generally considered fine to use kosher salt or any other type of ice melts, from rock salt to magnesium chloride, but you need to be much more careful with using salt on concrete at you can see in the videos below.
If you have a concrete driveway then instead of using kosher salt or any other ice melt that can damage the driveway consider using sand or bird seed to provide some traction on top of the ice, making it safer to walk and drive on.
The downside of using sand over salt is that it won't actually melt the ice it'll just sit on top of the ice.
Also if there is a fresh snow storm and new layers of ice are added then sand needs to be reapplied.
However the benefit of using sand is that it won't damage your driveway and when the ice melts it can be swept away into the garden and be added to the soil and it also won't damage plants in the runoff.
What is Kosher Salt?
Kosher salt is large and coarse grains of salt mined from salt deposits and not all kosher salt is kosher certified to meet the guidelines of a kosher standard diet.
Much like pink Himalayan salt grew in popularity in the late 2000s, kosher salt is becoming the new 21st-century salt craze and you won’t find many cupboards in the US without kosher salt.
In terms of appearance salts can be different in shape and size, however their main compositions are only slightly different. This is also true for kosher salt. For all intents and purposes kosher salt as almost identical in it's composition to regular salt, however it usually does NOT contain iodine which many believe gives it a much better taste.
Kosher salt is used in cooking. It can be easier to use kosher salt because of its larger size being easier to pick up and sprinkle over food as well as providing a crunchy texture that can add variety of sensations to your meal.
Kosher salt is also used as part of a diet by law in Jewish religion through a process called “koshering”. Just briefly, koshering is when the salt (kosher salt) is added to meats to soak up the blood of the animal so that it can be eaten. All of an animal’s fats, nerves, and blood are not part of a kosher diet so having kosher salt remove the blood is highly advantageous.
However, it's important to note that the name “kosher salt” generally refers to the size and shape of the grains of salt and it is not always certified kosher.
Salt is mostly made up of sodium chloride and is a naturally occurring mineral found on almost every continent in the world. Where many salts have high additives, kosher salt does not, so the bitter taste that comes with regular salt is not tasted in kosher salt.
How Does Kosher Salt Melt Ice?
Kosher salt melts ice just like most other salts that are filled with sodium chloride melt ice, by lowering the freezing temperature of the water.
Kosher salt, and numerous other types of salt, melt ice by lowering their freezing level. That’s why, around the world, we use salt on the roads and sidewalks in winter: to melt the snow and ice for a safer driving experience.
The act of thawing and melting ice with salt is called the “freezing point depression” because that’s exactly what salt does when it comes into contact with ice. It reduces the freezing and re-freezing of water by lowering the water’s freezing point which is at 32°F (0°C).
Because ice is generally coated with a thin top and outer layer of water, when salt touches the surface of the ice, the sodium chloride dissolves in the water which enables it to “melt”.
Instead of freezing at temperatures of 32ºF (0ºC) the new water/salt mixture may need temperatures as low as 0ºF (-18ºC) in order to stay frozen. If you've got temperature at say 23ºF (-5ºC) regular ice would stay frozen but ice mixed with kosher salt will actually melt and turn into a liquid.
The Scientific Behind Why Kosher Salt Melts Ice
When the water reaches its freezing point, the molecules in the water are essentially bonded together. Throwing sodium or calcium chloride (salt) onto the ice interrupts the process by breaking it down into two ions when it comes into contact with water: Sodium and chloride.
The sodium and chloride start moving through the water, taking up space in the tiny crystal formation and moving the organized crystals and molecules apart. Once the molecules have been separated, the sodium chloride has basically ruined any chances of the water forming ice links when it’s trying to go through its freezing process.
It’s at this point in the de-icing method we use the phrase “freezing point depression” as mentioned above.
Anytime particles, such as salt or alcohol, are added to a liquid you lower its freezing point. This is why vodka won’t freeze in a typical household freezer.
When roads are slippery with ice, it’s because there is usually a thin layer of water over the ice. So while the ice is trying to freeze the water, the water is trying to melt the ice. These molecules continue to react this way until an outside compound is added to the mix to either help the freezing process or the melting process.
Where adding more pressure helps the molecules bond together, salt acts as a solute and makes it more difficult for the molecules to bond. Adding sodium chloride, or calcium chloride, to the ice acts as a dissolvent that separates ions or breaks down the ions which results in the ice not being able to form itself.
Check out this article by Philip Schmidt who tested the salt and ice theory using kosher salt and claims out of all the methods he tried, kosher salt was the best option on the list for melting ice. I've also written an interesting article on why salt makes ice colder in items like coolers.
Kosher Salt Vs Regular Salt
Over 20 million tons of salt is used annually to melt icy roads and paths in colder regions of the world. 270 million metric tons of salt is produced annually with China being the leading salt producer in the world.
Kosher salt is made from sodium chloride and doesn’t contain any traces of iodine, minerals, and other additives like table salt might.
Here are the main differences between kosher salt and regular salt:
|Kosher Salt||Regular (Table) Salt|
|Grain||Large, coarse flakes||Small and fine grains like white sand|
|Mined from||Salt deposits||Salt deposits|
|Used for||Food seasoning, curing and smoking meats, pickling, koshering||Food seasoning, baking|
|Structure||Sodium chloride||Sodium chloride, iodine, anti-clumping additives|
|Benefits and disadvantages||Ease of use in cooking, pure flavor from lack of additives and minerals,||Can be used for all kinds of cooking and baking but because of the additional agents it can create a bitter taste if over-used|
|Price||Roughly 20% more expensive than table or sea salt. A 48 Ounce Morton kosher salt in Walmart is US$2.97||A 26 ounce Morton Iodized table salt in Walmart is US$1.12|
Himalayan pink salt, pickling salt, and coarse sea salt are similar to kosher salt because of their larger size so if using salt to de-ice a sidewalk or driveway, these salts will work similarly.
If you’ve read that salt can’t melt ice, try it for yourself at home and watch your ice blocks slowly melt away because of the sodium chloride in the salt. As mentioned above, the salt isn’t technically melting the ice but is rather stopping the ice, or water, from freezing or refreezing.
Both kosher salt and regular salt have high amounts of sodium chloride and will melt ice when they come into contact.
Depending on how much salt is used compared to how much ice you need to melt will determine how fast the ice melts.