Lesson of the Week: Adding Salt To Water To Make It Boil Faster

When I was young, I learned that before you boil water for cooking, you should add a pinch of salt. I always thought it was because it made water boil faster. Sadly, I found out today it has the opposite effect. Salt water boils slower than water without salt in it. Why is that?

Salt dissolves easily in water. After a few stirs, you have a salt water mixture. Since salt has a very high boiling point, water cannot boil while it's still mixed with salt. So, extra heat is needed to create the energy that separates salt from water. This need for extra heat causes the boiling point of the mixture to be higher than if it did not have salt mixed in. Raising the salt water to a higher temperature will of course take longer, so boiling salt water takes longer than regular water.

Also, the higher boiling point achieved by adding 60 grams of salt to water is less than a degree, so it won't help you very much cook at this new temperature.

Honestly, the only reason to add salt to water while cooking is to add flavor to the meal.