To a great extent, absinthe owes its notorious reputation to a chemical called thujone (pronounced thoo-ZHONE). Thujone is a monoterpene, related to both camphor and menthol, that occurs naturally in wormwood as well in sage, tarragon, tansy and commercial products such Vicks VapoRub. Classified as a convulsant poison by the U.S. Food and Drug Administration, thujone is often cited as the source of absinthe's toxicity as well as the source of its alleged psychoactive properties.
The emphasis on thujone as the active ingredient of absinthe has persisted largely because conventional wisdom held that vintage pre-ban absinthes contained far more thujone that the concentrations allowed under contemporary European law. In the 1990s, the European Community Codex Committee on Food Additives set a limit of 10 mg/kg of thujone in alcoholic beverages. The decision essentially legalized absinthe across Europe, although other restrictions on its production vary from country to country. (In the United States, the Federal Food, Drug and Cosmetic Law of 1972, which superseded Food Inspection Decision 147, prohibits detectable levels of thujone in finished products, thus maintaining absinthe's restricted status in America.)
In a widely read article, Wilfred Niels Arnold, a professor of biochemistry, speculated that pre-ban absinthes contained as much as 260 mg/kg of thujone. By contrast, at a measly 10 mg/kg, contemporary European brands appeared to be pale reflections of the potent pre-ban brands. In the minds of many, thujone content became the index of an absinthe's quality and authenticity.
No one, apparently, had ever bothered to actually test pre-ban absinthe. Enter Ian Hutton. Hutton, a British dealer in Belle Epoque antiques and absinthe aficionado, became acquainted with Emile-Gerard Pernot, great-grandson of the founder of the Emile Pernot distillery in Pontarlier. With the recent easing of France's absinthe laws, Pernot had begun producing absinthe again at the family's distillery, although by French law at the much-reduced strength of 90 proof. Hutton commissioned Pernot to produce for export a traditional absinthe using the old family recipe and at the vintage strength of 136 proof. The problem, Hutton feared, was that based on Arnold's calculations, the traditionally made product would far exceed EU thujone restrictions.
Hutton commissioned a gas-liquid chromatography (GLC) analysis of the custom product as well as a sample of pre-ban Pernod Fils to determine their thujone content. The results were shocking. Vintage Pernod Fils, the Holy Grail of absinthes, contained not 260 mg/kg of thujone but a mere 6 mg/kg. Un Emile 68, the custom absinthe, contained 10 mg/kg. "When we saw the results, we couldn't believe them," Hutton says. "The high levels quoted turned out to be based on wrong information that had been repeated over and over."
The results of the GLC analysis, published in September 2002 in the journal Current Drug Discovery, shot down once and for all the contention that pre-ban absinthes were somehow more potent than contemporary brands and that traditionally made products couldn't be produced under EU guidelines. It also enabled Hutton to begin importing Un Emile 68 to the United Kingdom. Today, many consider Un Emile to be the finest of the recent crop of artisanal absinthes produced since the loosening of European laws.
As for thujone's reputation as the psychoactive component of absinthe, Ted Breaux is unequivocal: "Thujone is not a drug," he says. "It doesn't behave like a drug. It's not a psychoactive, psycho-hallucinogenic compound. And even it were, it would have to have the pharmacological potency of morphine to be effective in the concentrations we're talking about. It doesn't."
Thujone occurs naturally in wormwood (pictured) and is often cited as the source of absinthe's toxicity and psychoactive properties.