I felt rather inspired and compelled to write this article after an enjoyable meetup with Mr Stephan S. from Mexico, whom had stopped by Singapore for a while. I’m extremely impressed the olfactory prowess of Stephan which I believe to be a notch above mine (I hope to invite him to write a guest article one day on his expertise on copal in incense!). He had reflected to me that he had purchased some incenses which smelt different when burnt in different places, such as in Singapore versus back at home in Mexico where he lives at a higher altitude of 1800 metres above sea level.
It made me extremely glad that there was someone else whom had noticed this issue before, and I was not imagining things.
The biggest interference with incense burning is the relative humidity and temperature. At very high humidities, such as in Singapore where you can have an RH of 100% at night, fine incenses can smell a little muted, dull. Apart from turning on the air conditioner to dry the air and cool the air to about 25 degrees celsius before I sample an incense, it took quite some experiments to figure out the optimum burning angle for myself in such environmental conditions. There is no “hard and fast” rule to this due to weather fluctuations, in a drier environment and for more delicate incenses I prefer to burn them totally upright, and if something doesn’t smell very right/good to me, I do vary the angle which often helps.
The typical zone where fragrance is being released together with the smoke, is the zone just below the lit end of the incense stick. The burning temperature of this zone can vary due to recipe differences, incense compaction, incense format, composition, (of which all you cannot control) and incense angle which you can vary yourself.
For high end incenses, i.e. premium kyara sticks such as Translucent path of Shoyeido, Seijudo’s aloeswood and kyara incenses, Minorien’s Kyara Ryugen, etc, the burning temperature of this zone if you attempt to read with an infrared thermometer, is around 165 to 180 degrees celsius. Most regular incenses have burning temperatures that range between 220 to 260 degrees celsius.
How do these companies achieve a lower burning temperature with their incense sticks? This is usually done by varying the composition with the usage of resins, ground shell powders, light soaking in oils, and most importantly, addition of high quality charcoal powder. The charcoal powder helps to moderate temperatures, assist with heating/combustion of resins at the right temperature, and strongly reducing burnt binder notes!
The importance of the burning angle of an incense stick is something that cannot be undermined, and yet it is a subject that nobody talks about. If you light two incense sticks, one totally upright and the other totally upside down, you will realize that the upside down stick will burn up to 25% faster!
Almost at the end of burning, you can see the differences in length and subsequently burning time.
Also, if you burn a stick upside down, the smoke is thicker, whilst being upright, the smoke is much more delicate. This difference is due to the higher burning temperature when the stick is upside down than when the stick is upright! You can strike a match and experiment for yourself, an upright match stick burns slower than a horizontal or tilted below horizontal match stick (be careful not to burn yourself!). This is due to the hot incense smoke that rises due to convection, when the lit incense stick is totally upright, the heat of the lit end and the smoke is allowed to rise quickly with little contact with the unburnt area beneath the lit end. However when the stick is upside down, the heat of the lit end and the smoke, when rising will go past the unburnt part of the incense stick, contributing to heat conservation and thus a higher resultant temperature. The difference in temperature is about 20 degrees celsius or more. This gives one some room to play with to better optimize the incense burning process.
I have also noticed that for incenses that have higher and more obvious binder contents, having the stick burn hotter by having it below horizontal often results in a distasteful, “burnt” smell in the air, and this can be reduced by burning the stick totally upright. The next time when you burn an incense stick, try these experiments yourself! It may help enhance your incense experience.