Boil

To boil is to cook food in water or another liquid at its boiling point, where vapour bubbles form throughout the liquid and rise continuously to the surface. At sea level, pure water boils at approximately 100°C (212°F); the boiling point decreases at higher altitudes and varies with dissolved substances and pressure.

Common culinary uses

• Cooking pasta in boiling water.
• Cooking potatoes, often starting them in cold water so they heat evenly.
• Blanching vegetables or loosening skins from tomatoes.
• Preparing eggs and other foods where a boiling liquid is specified.

Boiling versus simmering

A rolling boil has vigorous bubbles throughout the liquid. A simmer is gentler, with smaller bubbles and less agitation. Many stocks, braises, delicate proteins and sauces benefit from simmering rather than a hard boil, which can break emulsions, agitate solids or toughen delicate foods.

Chef’s tip: Match the heat to the ingredient. Use a full boil when rapid cooking or blanching is required, and reduce to a simmer when gentle extraction or tender cooking is the goal.

Key distinction: Boiling describes the liquid’s cooking state; simmering is a gentler state below a rolling boil.