What Is the Temperature of Boiling Water? Here’s Why It Matters

Compared to roasting or grilling, boiling might not be the most exciting cooking method, but what it lacks in pizzazz it makes up for in practicality. We boil water for all kinds of things, from cooking pasta to blanching vegetables, so it pays to understand a little bit about the process. Let’s dive in.

Boiling can refer to heating a liquid until it begins to turn to vapor, as well as to the act of cooking food in boiling water. In either case, the temperature of boiling water is exactly 212°F (100°C) at sea level. This can vary slightly depending on altitude, meaning that at a higher altitude, water may sometimes boil at a temperature just under 212°F.

If you cook with food thermoometers often, and want to know how to calibrate the thermometer properly, you’ll want to look for this number. This is a great way to make sure your thermometer is actually working properly and giving you accurate readings.

Recipes may call for simmering rather than boiling. Simmering takes place just before a rolling boil, at a temperature between 195°F and 212°F. A true boil takes place at 212°F and above.

You may have heard that adding salt to water will make it boil faster, but, unless you’re adding a ton of salt, the difference is negligible. We’re talking seconds, not minutes. That said, for many boiling applications, it’s a good idea to make sure your water is well-salted for seasoning purposes.

While water boils at 212°F (100°C) at sea level, the higher you go, the slower water will boil. This is due to the lower air pressure of higher elevations. Liquids boil when their internal vapor pressure reaches the same levels as the atmospheric pressure. When the atmospheric pressure is lower, the water molecules need less energy to become vapor, and thus boiling occurs at a lower temperature at higher altitudes.