In microbiology, an incubator is a device for controlling the temperature, humidity, and other conditions in which a microbiological culture is being grown. The simplest incubators are insulated boxes with an adjustable heater, typically going up to 60 to 65 °C (140 to 150 °F), though some can go slightly higher (generally to no more than 100 °C). More elaborate incubators can also include the ability to lower the temperature (via refrigeration), or the ability to control humidity or CO2 levels.
Most incubators include a timer; some can also be programmed to cycle through different temperatures, humidity levels, etc. Incubators can vary in size from tabletop to units the size of small rooms.
Incubators also contain certain features such as the shake speed, measured by revolutions per minute. As for temperature, most commonly used is approximately 36 to 37 degrees Celsius. Most bacteria, especially the frequently used E. Coli, grow well under such conditions. For other experimental organisms, such as the budding yeast Saccharomyces cerevisiae, a growth temperature of 30 °C is optimal.
In field conditions if no such incubator is available, and particularly in remote or less-developed areas, some people keep samples at close to body temperature by inserting the samples into their socks. The phase-change incubator is intended as a more reliable and consistent way of performing this task simply and affordably.