Why do compact fuels burn slowly?

Compact fuels burn slowly primarily because air cannot circulate freely around them. When fuels are compacted tightly, it reduces the availability of oxygen, which is essential for combustion. Without sufficient airflow, the combustion process is hindered, resulting in a slower burn rate.

While moisture content can affect the burn rate as well, the fundamental reason for the slow burning of compact fuels is the restricted airflow. The presence of chemicals may influence the combustion characteristics, but it is the lack of oxygen that directly impacts the combustion process in this scenario.