Slow Cooker - Design

Design

A basic slow cooker consists of a lidded round or oval cooking pot made of glazed ceramic or porcelain, surrounded by a housing, usually metal, containing an electric heating element. The lid is often of glass seated in a groove in the pot edge; condensed vapour collects in the groove and provides a low-pressure seal to the atmosphere. The contents of a crock pot are effectively at atmospheric pressure, despite the water vapor generated inside the pot. A crock pot is quite different from a pressure cooker and presents no danger of an abrupt pressure release.

The ceramic pot, or 'crock', acts as both a cooking container and a heat reservoir. Slow cookers come in capacities from 500 ml (16 oz) to 7 liters (7.4 US quarts). Due to the placement of heating elements (generally at the bottom and often also partway up the sides), there is usually a minimum recommended liquid level to avoid uncontrolled local heating.

Many slow cookers have two or more heat settings (e.g., low, medium, high, and sometimes a "keep warm" setting); some have continuously variable temperature. A typical slow cooker is designed to heat food to 77 °C (170 °F) on low, to perhaps 88-93 °C (190-200 °F) on high. Many recipes that include sauce or liquid will reach the boiling point around the edges, while food in the center remains gently cooked. This may be because slow cooker settings are based on wattage, not temperature.