There are three common methods of manufacturing incense sticks; Hand-rolled, Machine dipped, and Pressed.
(a) Hand Rolled:
The best incenses are invariably hand made.
A mixture of the fragrance “dough” is made by mixing finely ground powder of coconut husk, carbonized coconut/jute husk powder and natural glue or bees wax. The reason for using coconut husk powder, also known as “coco peat”, is its unique combination of very high calorific value and capillarity of the fibrous coco peat.
High calorific value will produce intense heat on burning, enabling the vaporizing of aromatic oils, and capillarity ensures the absorption of maximum quantity of aromatic substances into the incense mix.
This mixture is then “hand rolled” into a thin strip of bamboo which will hold the mixture together.
The best grade of masala incenses are made by blending the essential aromatic compounds into the incense mix and then rolling the blended mixture into the bamboo strip. The masala incense sticks are then matured for a certain period under controlled atmospheric humidity.
The maturing process of a masala incense stick is the single most important factor in determining the quality of the fragrance of an incense stick.
Incense manufacturers located outside India make their incense by dipping the un-perfumed hand rolled sticks into the required essential/carrier oil blends to make the required fragrance.
Hand rolled sticks are usually dark-wood-beige in colour.
(b) Machine dipped:
Other manufacturing methods include “machine dipping”, where sticks, placed in a tight frame is dipped into a thick fluid of carbonized wood paste and later dipped into an oil pot containing the required fragrances.
These incenses are cheap and of less value as most manufactures replace carrier oils and essential oils with petroleum derivative substitutes.
Commercial grade incense are made this way as it enables to save the labour costs and replace essential oils and expensive resins with petroleum derivatives and perfumes.
This makes the incense burn for less than half the time of hand rolled sticks, and may even be quite toxic. The fragrances of such sticks may not be the same before and after lighting the incense stick.
Machine dipped sticks are black in colour but also sometimes comes in other colours.
However, many reputed manufacturers do make high grade black coloured hand rolled incense sticks.
These sticks are very expensive and is best suited for tropical climatic conditions with over 70% atmospheric humidity.
The third type of manufacturing employs a mechanized system to “press” the incense mix like pasta to form long sticks without the bamboo strip.
Most cheap incenses made in China are made this way.
Most of the Tibetan, Nepaleese and Japaneese incense sticks are also made this way.
As this type of sticks lack the axial bamboo strip, the incense stick is held in shape by adding adequate quantities of binders or adhesives. It should be noted that when lit, these incenses also burn the binders and glues present in the incense mix.
Pressed incenses come in all kind of colours. Read about coloured incense sticks below.