Long-term stability of thujone, fenchone, and pinocamphone in vintage preban absinthe.

Research was conducted to ascertain whether analyses of vintage absinthe samples represent their original composition in the early 1900s. Absinthe stored in traditional green glass bottles and irradiated with ultraviolet light for up to 200 h exhibited unchanged composition. Samples stored in clear glass exhibited an 18% reduction in beta-thujone content and a concurrent decoloration. These experiments indicate the stability of thujone in vintage absinthes, as these were stored in green glass bottles. The preserved color of the preban absinthes subjected to analysis indicates that no significant light exposure occurred throughout the duration of storage, and therefore provides indirect proof that no loss of terpenes occurred. The stability of absinthe was further demonstrated through the reanalysis of samples from 2001-2005, which exhibited no changes in thujone content as of 2008. A previous evaluation of preban absinthe was therefore valid and not confounded by significant thujone deterioration over time.

Chemical composition of vintage preban absinthe with special reference to thujone, fenchone, pinocamphone, methanol, copper, and antimony concentrations.

Thirteen samples of authentic absinthe dating from the preban era (i.e., prior to 1915) were analyzed for parameters that were hypothesized as contributing to the toxicity of the spirit, including naturally occurring herbal essences (thujone, pinocamphone, fenchone), methanol, higher alcohols, copper, and antimony. The total thujone content of preban absinthe was found to range between 0.5 and 48.3 mg/L, with an average concentration of 25.4 +/- 20.3 mg/L and a median concentration of 33.3 mg/L. The authors conclude that the thujone concentration of preban absinthe was generally overestimated in the past. The analysis of postban (1915-1988) and modern commercial absinthes (2003-2006) showed that the encompassed thujone ranges of all absinthes are quite similar, disproving the supposition that a fundamental difference exists between preban and modern absinthes manufactured according to historical recipes. Analyses of pinocamphone, fenchone, base spirits, copper, and antimony were inconspicuous. All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome "absinthism".