“Water boils faster if you add salt.”

It's a widespread kitchen tip: add salt to water to make it boil faster. This common belief, however, is a classic culinary myth. The truth is quite the opposite; introducing salt to water actually elevates its boiling point, meaning it requires slightly more energy and therefore more time to reach a boil. This phenomenon, known as boiling point elevation, is a fundamental principle in chemistry where dissolved solutes interfere with the water molecules' ability to transition into a gaseous state, demanding a higher temperature to overcome these intermolecular forces.

The scientific evidence clearly shows that for water to boil, its vapor pressure must equal the surrounding atmospheric pressure. When salt is dissolved, the salt ions occupy space among the water molecules, effectively reducing the concentration of water molecules at the surface. This makes it harder for water molecules to escape into the vapor phase, thus requiring a higher temperature to achieve the necessary vapor pressure for boiling. While the increase in boiling point for typical amounts of salt used in cooking is relatively small—often less than a degree Celsius—it nonetheless means the water takes longer, not shorter, to boil.

So why do so many people swear by this method? The misconception likely stems from a few factors. One significant reason is that once the water *is* boiling, the slightly higher temperature of salted water can indeed cook some foods, like pasta, marginally faster. People might attribute this accelerated cooking of the food itself to the water reaching a boil more quickly. Additionally, the effect of a small amount of salt on boiling time is so minimal that it's often imperceptible to the casual observer, leading them to misinterpret other perceived benefits or simply perpetuate anecdotal evidence without scientific verification.