Convection

Convection is heat transfer through the movement of a fluid — either air (in an oven or grill) or liquid (in a water bath or deep fryer). Hot fluid rises, contacts the cooler food surface, transfers energy, cools slightly, and moves away. Fresh hot fluid replaces it, maintaining a continuous heat delivery cycle.

In an oven set to 250°F, convection currents carry thermal energy from the heating element to the steak's surface. The efficiency depends on air velocity — a convection oven with a fan moves air faster, delivering heat roughly 25% more efficiently than a standard oven. This is why convection ovens cook faster at the same temperature setting.

Natural vs. forced convection: In a standard oven or covered grill, hot air rises and cool air sinks naturally (natural convection). In a convection oven or with a grill's draft vents open, a fan or chimney effect forces air movement (forced convection). Forced convection is more efficient and more even.

Convection in sous vide: Water is about 25 times more thermally conductive than air. A circulating water bath combines water's superior heat transfer with forced convection from the circulator pump. This is why sous vide heats food more evenly and efficiently than an oven at the same temperature.

Practical tip: During the reverse sear oven phase, convection is your primary heat transfer mechanism. A convection oven setting (if available) shortens the cook time by 15–20% compared to standard mode.