The Bible states (Ex. 30:34), "G-d said to Moses: Take fragrances such as balsam, onycha, galbanum, and pure frankincense, all of the same weight, as well as other specified fragrances."
The incense which was offered in the Holy Temple was made from eleven different ingredients, only four of which are mentioned by name in the verse above. The identity of the other seven spices has been passed down in the Oral Tradition. As is the case with regard to many other areas of Temple study, the exact classification of these ingredients is the subject of serious research and scholarship. Many of these are rare, and some can be obtained only in exotic and distant lands.
The method, or recipe, for preparing the special incense offering from these ingredients was a closely-guarded secret, passed down from generation to generation within the ranks of one particular family known as Avtinas. In addition to the identity of the spices and the exact amounts and manner in which they are prepared, the clan protected another important secret of their trade: The identity of an herb known in Hebrew as ma'aleh ashan, literally "that which causes smoke to rise." This herb has a quality which enabled the smoke from the incense to rise up to heaven in a straight column. In our own time, some have speculated that this may be the plant Leptadenia pyrotechnica, which contains nitric acid.