Kretek cigarettes contain clove buds in addition to tobacco in
the filler (up to 40%) that gives them their unique taste and smell.
In addition to the clove buds they also contain flavor ingredients according to the smoking preferences of the different consumer
groups. Other ingredients are used to facilitate tobacco processing
and to preserve tobacco moisture (LaVoie et al., 1986). Historically,
many tobacco farmers applied a substance mixture of undisclosed,
secret composition, the sauce, already to the tobacco before delivery
to the cigarette manufacturers (Polzin et al., 2007). The sauce
consisted mainly of flavors and substances that release flavors
upon combustion. Today, at least for the main kretek cigarette
manufacturers, the sauce has been replaced by the addition of a
mix of defined flavoring and moistening substances to the tobacco
in the factory with full disclosure of the single ingredients by the
vendors to allow a review whether a single ingredient might
increase the inherent toxicity of the smoke at the level used.