Compounds other than ethanol in an alcoholic beverage may be due to:
(1) chemicals or additives in source materials
(2) consequences of normal fermentation and distillation (normal congeners)
(3) consequences of an error in fermentation or distillation (toxic congeners)
(4) normal additives following distillation (preservatives, coloring agents, etc)
(5) accidental contamination
(6) intentional adulteration
Alcohols that may occur as normal congeners:
(1) methanol
(2) n-propanol
(3) isobutanol
(4) n-butanol
(5) isopentanol
(6) hexanol
(7) isoamyl alcohol
Other compounds may occur as congeners include:
(1) acetaldehyde
(2) ethyl formate
(3) ethyl acetate
(4) ethyl carbamate
Risk factors for exposure to toxic congeners:
(1) unregulated or illegal alcohol products (moonshine, etc)
(2) inexperienced distiller (including distillates at temperatures below or above where ethanol should occur)
(3) consumption of large amounts of an alcoholic beverage containing potentially toxic congeners
If a person develops toxic effects associated with an alcoholic beverage then an attempt should be made to submit a sample of the beverage for chemical analysis. Unfortunately the effects of a toxic alcohol present in low amounts may be difficult to document if it is consumed over many years.
