The Filter or System these can range from metal filters to carbon filters, these are used to regulate the smoke and trap particles of tobacco. The secret to a steadily burning tobacco varies with the type of blend. Each type burns and packs differently. Tamp any remaining tobacco, relight and continue smoking. Cake is the carbon that forms inside of your bowl.
Proper cake is important.
It absorbs moisture, giving you a drier smoke and helps to retain the flavor of the tobacco, resulting in a sweeter smoke.