The glowing end of a cigarette, often called the cherry or the combustion zone, generates intense heat that fluctuates significantly based on the smoker’s action and the amount of oxygen reaching the burning tobacco. Understanding this temperature variability is important because it governs the chemical compounds produced and the physical hazards associated with the product. The dramatic difference in heat output between an actively smoked cigarette and one left to smolder is one of its most defining characteristics.
The Peak Temperature of the Combustion Zone
The hottest point within a burning cigarette occurs during a draw, or puff, when forced airflow delivers a concentrated supply of oxygen directly to the burning material. This creates an environment for efficient combustion, causing the temperature at the core of the cherry to spike dramatically. Scientific measurements place the peak temperature in the range of 850 degrees Celsius to 950 degrees Celsius.
This temperature range (1,560 degrees Fahrenheit to 1,740 degrees Fahrenheit) is hot enough to melt some metals. Studies using fine-wire thermocouples have consistently recorded these high maximums during the two-second duration of a standard puff. The high temperature is directly responsible for the rapid thermal decomposition of the tobacco, generating the thousands of chemical compounds found in cigarette smoke.
Temperature Dynamics Resting Versus Active Puff
The temperature of a cigarette changes drastically when it is not being actively smoked, entering a phase known as smoldering. During this resting period, the lack of forced airflow limits combustion to the slow diffusion of oxygen through the wrapping paper and the tobacco. This oxygen-starved environment results in incomplete combustion and a significant temperature drop. The smoldering cherry typically maintains a temperature between 400 degrees Celsius (750 degrees Fahrenheit) and 600 degrees Celsius (1,100 degrees Fahrenheit). This lower temperature reflects the reduced rate of burning.
The temperature mechanism reverses immediately when a smoker takes a drag, rapidly forcing air into the ember and causing the temperature to surge back toward its maximum. This rapid thermal cycling between the smoldering phase and the hot puffing phase is a unique characteristic of the combustion process. The forced infusion of oxygen acts as a bellows, quickly re-igniting the tobacco into a high-temperature burn.
Fire and Burn Risk Implications
The high temperatures sustained by a cigarette, even in its smoldering state, pose a substantial fire risk to common household materials. Many materials found in homes, such as upholstered furniture, bedding, and synthetic fabrics, have ignition temperatures lower than the cigarette’s resting temperature.
For instance, a cigarette smoldering at 450 degrees Celsius is more than hot enough to ignite materials that have an ignition point well below 300 degrees Celsius. This disparity explains why unattended cigarettes are a leading cause of residential fires and associated fatalities annually in the United States.
The danger is compounded because a smoldering cigarette can sit on a material for several minutes before enough heat transfers to cause a flame, allowing fires to start unnoticed. Beyond the fire hazard, the hot tip presents a direct burn risk upon brief skin contact.
Even the lower smoldering temperature of 400 degrees Celsius is sufficient to cause severe, third-degree burns within seconds. This physical hazard is a direct consequence of the thermal energy stored in the glowing cherry.