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Absinthe (Molecule of the Month for January 1999)

Thujone



Absinthe, a high proof, controversial herbal spirit drink, is available again in Britain after an 85-year absence. Twice the strength of most other spirits, the emerald green tipple of choice for 19th-century artists and intellectuals -- along with millions or ordinary Europeans -- has been banned in France, Belgium, Switzerland and the US since just prior to the first world war. Now, to the horror of some but the delight of many, a few British companies have secured contracts with tiny Spanish and Czech absinthe producers after discovering that the drink was never formally prohibited in the United Kingdom.

Green Bohemia market 'Hill's Absinth' -- the Czech spelling is idosyncratic --as an exotic and supposedly potent way of celebrating the new millennium for those desperately seeking a new kick. Critics call Hill's 'Windex' and 'gargle'. The liquor contains no detectable thujone.

Other companies such as New Millenium Products are importing 'Deva Absenta' from Spain. This is a more solid product. Sebor UK imports the best of the Czech labels, but traditionalists dislike its lack of much anise base flavor.

The green drink's revival has provoked astonishment among alcohol-awareness campaigners who accuse such firms of giving young people the ammunition to drink to dangerous excess. However, other high proof spirits sich as 151 Bacardi rum and 136 proof Chartreuse Green liqueur -- a close cousin of absinthe, were already on the market. Adolescents out to seriously abuse their hepatic systems usually prefer cheap 95% grain neutral spirits and grape juice, a concoction known as Purple Passion. These absinthes are simply out of that price class. 40 to 76 sterling for a liter of 55 to 70 proof absinthe simple can't compete for the cheap-drunk market.

Imported from Switzerland (where it started as a patent medicine) to France in 1797 by Henri Louis Pernod, the light green drink is made by steeping dried herbs, including some common wormwood (Artemisia absinthium), in ethyl alcohol and then distilling the steep liquor. The distillation is esential as wormwood contains extraordinarily bitter compounds called absinthins which must be excluded from the distillate. Fortunately absinthins are alcohol insoluble, while the rest of the essential oil is volatile with alcohol vapor. The principal herbs are familiar culinary spices anise and fennel, their essential oils being mainly anethole. The product is then treated with Roman wormwood (A.pontica) and other herbs in a delicate and difficult final step. These add finishing flavors and fragile chlorophyllic green pigment -- easily denatured by light or heat. Less traditional brands use food coloring and usually go for a dramatic emerald green (or blue, yellow, even red!) Really authentic absinthe is a pale vivid green like the gemstone Peridot. A New Orleans chemist and microbiologist, Ted Breaux, has spent seven years studying absinthe and has replicated the recipe for one of the most important Belle Epoch brands, Eduoard Pernod. Breaux is a perfectionist about absinthe making, and owns two bottles of century old premium Pernods, which greatly facilitated his efforts. Breaux' absinthe (soon to be commercialized outside of the US) is believed by many to be the finest the world has seen since 1915.

The presumed active ingredient in wormwood's oils, alpha-thujone, has a similar molecular structure to menthol, a-pinene, eucalyptol, camphor and other monoterpenes. Formerly believed to have a THC (cannabinoid) structure-activity relationship and mechanism, a-thujone is now known to modulate only an entirely different receptor site, the GABA (gamma-aminobutyric acid) system. GABA moderates the firing of neural synapses; a-thujone mildly antagonizes such inhibition.

The traditional method of 'presentation' (drinking) involves charging a perforated 'absinthe spoon' with a sugar cube and placing it over an 'absinthe glass' which greatly resembes a modern parfait ice cream glass. The glass has a line around it demarking the proper amount of absinthe it should contain so that when full, the glass will hold the proper 5 parts of water fo 1 part absinthe -- almost no one ever drinks this liqueur neat, save for a few show-offs. The water is trickled from a carafe or 'absinthe fountain' over the sugar cube which slowly dissolves. As the sugary water dilutes the alcohol, the herbal oils in the high proof alcohol solution come out of solution, being almost insoluble in water. This liberates the hugely floral bouquet and produces a milky off-white drink similar to Greek ouzo or Mideastern arak or European anisette -- all anise based drinks like absinthe. The clouding effect is termed the louche, and is of great aesthetic appeal to absintheurs. Modern variations involving setting the absinthe alight are mere cheap melodrama.

Absinthe rose to popularity in the mid 19th century only after the decades long phylloxera blight of the vineyards caused the price of wine to soar and its availability to plummet. By the late 1800s, La Fee Verte - the Green Fairy as absinthe was nicknamed - was being consumed with such fervour by the Parisian artistic and literary set (and nearly everyone else) that the cocktail hour was renamed L'Heure Verte. Among its devotees were Oscar Wilde, Ernest Dowson, Pablo Picasso, Artur Rimbaud, Paul Verlaine, Alistair Crowley, and Charles Baudelaire. Van Gogh's ear-cutting incident is popularly attributed to absinthe intoxication. However, Van Gogh was also fond of eating his oil paints and drinking turpentine (principally a-pinene) and had long been highly unstable and self-destructive.

The advent of the prohibition and Christian-temperance movements coincided with the success of the vintners in reconstituting their industry with New World cuttings immune to the insect blight. The vintners next urgently sought a way to recover their millions of customers and woo them from the Fairy's embrace. They joined forces with the anti-alcohol movements, who had arisen in response to the "Great Binge" of the Belle Epoch. Pamphleteers (notably Zola) and journalists were enlisted or employed; politicians and legislators cajoled or suborned. A massive anti-absinthe campaign in the press along with some lurid murder cases -- conveniently but unconvincingly laid at the Fairy's door -- led to the domino effect of European bans between 1910 (Switzerland) and 1915 (France).

But were wormwood and its active agent, a-thujone, such menaces? A.absinthium has been used for millenia as a vermifuge and digestif tonic. And contrary to general opinion, a-thujone does not only occur in wormwood. It is a major component of the essential oils of such homely culinary herbs as sage, tansy, and tarragon. No one seems to be having neurotoxic problems from eating these commonplace spices. Absinthe was never banned in Spain, Portugal and a few other European countries, and its production and consumption in those places never ceased. In Switzerland's francophone Jura region bootleg absinthe called La Bleue has been produced clandestinely ever since 1910; estimates put its bootleggers at about 130, making more than 50,000 liters a year, little of which ever leaves Switzerland. Yet the folks in Neuchatel seem no worse for the wear. Those mountains are famous for ergotism not absinthism.

The EU allows absinthe of commerce to contain up to 10 mg/Kg -- equivalent to parts per million -- which is mild compared to the estimated 60-90 mg/Kg of premium Belle Epoch absinthes. But several modern Spanish and Czech brands actually contain no detectable thujone (and therefore can be presumed to have been made without A.absinthium) while some pastis -- fake absinthes introduced after the bans -- may contain more than 30 mg/Kg. Some vermouths -- the name is a derivative and corruption of wormwood which is used in flavoring these blended wines -- contain more a-thujone than many absinthes. Thus the martini is a chemical cousin of absinthe!

a-Thujone meanwhile is an important component in salves, perfumes, creams, etc. usually as a counter-irritant. The familiar Vicks Vap-O-Rub one's mother rubs on their chest for rlief from a cold contains thujone and other terpenes. So does Absorbine Jr. The anti-insect and preservative properties of white cedar used for clothes chests is due to the thujone in the wood; the classical name for white cedar is Thuja, whence the terpene gets its name. Van Gogh's doctor sentimentally planted a thuja tree at Vincent's grave.

In summary, thujone and absinthe were unjustly maligned and demonized, for a combination of commercial and ideological (even religious) reasons. Switzerland where cannabis is legal (and often steeped in vodka) still bans absinthe despite its ready availability. The USA still prohibits absinthe but does not presently make any special effort to interdict small quantities entering for personal use. In Europe, Pernod-Ricard survives as the continent's major beverage producer, but to afficianados, the name Pernod will always conjur up the Green Fairy and her 'opal wand'. Taken in moderation as all alcoholic drinks should be, absinthe is just one of many pleasant aperitifs, albeit one with a far more interesting history than most.

Don Walsh, who undertook the update of this page, is an organic chemist living in Bangkok, Thailand, where he serves as managing director of Jade Liqueurs Co.,Ltd. He was, some three decades ago, a research assistant to Prof.Emeritus Jack H.Stocker of the University of New Orleans -- which city, also his home town, was center of American absinthe culture until the ban in 1915. Mr.Walsh can be reached by email at cjade@ksc.th.com

Formal Chemical Name (IUPAC)
1-isopropyl-4-methylbicyclo[3.1.0]hexan-3-one

References

http://en.wikipedia.org/wiki/Absinthe

Picture of Absinthe 3D model

click on the picture of  Absinthe above to interact
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Absinthe structure
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Picture of Absinthe

C10 H16 0



Update by Don Walsh
(Molecule of the Month for January 1999 )

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