“Adding salt to water makes it boil faster”

Many home cooks instinctively reach for the salt shaker when bringing a pot of water to a boil, convinced that this simple addition will speed up the process. This widely held belief, however, is a common misconception. Far from accelerating boiling, adding salt to water actually causes a slight increase in its boiling point. This means that salted water must reach a marginally higher temperature before it begins to boil, technically taking a tiny bit longer to reach that stage compared to unsalted water.

The science behind this phenomenon is rooted in chemistry, specifically in the colligative properties of solutions. When salt, or sodium chloride, dissolves in water, its ions disrupt the natural arrangement of water molecules. These dissolved particles make it more difficult for the water molecules to escape into the air as steam. Consequently, more energy, and thus a higher temperature, is required to overcome these molecular interactions and initiate the boiling process. For the small amounts of salt typically used in cooking, this effect is so negligible that it is practically imperceptible.

The persistence of this myth likely stems from a few sources. One reason could be the observation that adding salt to already hot or boiling water can cause a sudden burst of bubbles. This visual effect, however, is not due to faster boiling but rather the rapid release of dissolved gases from the water as the salt crystals provide nucleation sites. Another contributing factor might be the association of salt with other cooking processes where it does seem to have an immediate impact, such as drawing moisture out of vegetables, leading to a generalization about its effects on water temperature.