Incense is created in a Scent Lab, using an Incense Prong to mix combinations of Herbs, Resin and petals from any of the Rose of Ra varieties.
Incense is burned in an Incense Holder. Standing near a lit burner causes you to inhale incense, which appears to affect attributes with the effect stacking on top of food and aqueduct water tower bonuses, and lasting approximately 15 minutes. Some analysis is going on at the Scents page.
To start a batch you need 20 Cactus Sap and 4 Charcoal.
To add Herbs or Resins you need an Incense Prong.
You can start and complete a batch without any herbs or resins.
The quality of an incense varies significantly from batch to batch.
Adding resins and herbs can change the scent, quality and attribute effects of an incense. The quality, scent and attribute effects of an incense are identified by burning a little pinch of the mixture. The information is reported in the main chat tab.