Thujone and absinthe : introduction

Thujone – pronounced “thoo-jone” with a soft ‘J’ – is a naturally occurring substance, also found in the bark of the thuja, or white cedar, tree, and in other herbs besides wormwood – including tansy and the comon sage used in cooking. Aside from absinthe, other popular liquors, including vermouth, Chartreuse, and Benedictine, also contain small amounts of thujone. In fact, vermouth, which was originally made using the flower heads from the wormwood plant, takes its name from the German “wermut” (“wormwood”).

Extremely high doses of thujone are dangerous, and have been shown to cause convulsions in laboratory animals, but the concentration of thujone actually found in absinthe is many thousands of times lower than this.

Thujone’s mechanism of action on the brain is not fully understood although certain structural similarities between thujone and tetrahydrocannabinol (the active component in marijuana) led to some speculation in the 1970’s that both substances have the same site of action in the brain. Doubt was cast on this hypothesis almost immediately, and more recent scientific research has completely discredited this idea.

Some researchers have now hypothesised that the reputed “secondary effects” of absinthe have nothing directly to do with thujone at all – if they in fact exist at all, they may be caused by the interaction of some of the other constituent herbs ( fenchone in fennel, pinocamphonethe in hyssop, and the anethole in anise, have all been shown to cause epileptiform convulsions in laboratory animals when administered in very large doses).

The effect of well-made absinthe varies from person to person, but is typically no more marked than the mild “buzz” one gets from drinking tequila. Generally, it can best be described as a kind of heightened clarity of mind and vision, warmed by the effect of the alcohol. This seems to wear off after 20 or 30 minutes. Some users report unusually vivid dreams. Since absinthe is 55%-72% alcohol, the alcohol’s effects will in any event limit the amount of thujone you can ingest. Most modern “legal” absinthes, in keeping with EU regulations, contains less than 10mg of thujone per litre, and recent research has shown that pre-ban Pernod Fils, contrary to speculation by several authors, including Strang and Arnold in a widely quoted 1999 British Medical Journal article, also had relatively low thujone levels.

Increasingly it seems clear in fact that well-made absinthes following authentic traditional recipes seldom have thujone levels much in excess of 35mg/l, the EU standard for thujone in bitters (a category that can, in practice, include absinthe), and many quite naturally fall under the 10mg/l level. It seems that irrespective of the quantity of wormwood used, relatively little thujone makes it through the distilling process into the final distillate. So the entire historical demonization of absinthe based on its allegedly high thujone content now appears to have been based on a wholly false premise.

The high thujone levels claimed by many Czech and German made “absinths” are invariably false (in fact, some of these products, when analysed by gas chromatograph and mass spectrometer, show no detectable thujone at all).

As a rule of thumb, any absinthe claiming exceptionally high thujone levels should be avoided, as it’s almost certainly a poor quality oil-mix, supported by bogus marketing hype.

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