Friday, June 20, 2008

Absinthe and Thiujone: A Modern Study

Absinthe. It's the drink of legend, and featured in many horror stories. It's shrouded in mystery, but modern chemistry is now shedding light in that greenish fog. Lovecraft, the chemist-wanna-be, would appreciate this article.

In the Chemical and Engineering News of 16 June 2008, a letter to the editor revealed this information.

“Absinthe Myths Finally Laid To Rest” was an interesting read, but those of us at Amalgamated Brewing disagree with the once-and-for-all evidence claimed by Dirk W. Lachenmeier (C&EN, May 5, page 42). Absinthe, like any alcoholic beverage, is a living, dynamic moiety and cannot be assumed to go unchanged during many years of storage. To the contrary, the complex mixture of volatile components in the “green fairy” makes this beverage particularly susceptible to chemical and physical changes.

Thujone is fairly volatile (BP 84 °C), and this small aliphatic ketone can be assumed to be rather reactive. We prepared a fresh 100-ppm standard of α-thujone (Aldrich 89231; 1058112 24706082) in a 50% ethanol/water solution to quantify levels of thujone in wormwood samples. The standard was stored in several tightly sealed glass vials to be used at a later date. After four months, these standards were found to contain less than 10 ppm thujone when compared with a freshly prepared solution.

To the credit of the study, we have also found the thujone content of the wormwood samples tested to date to be very low. Following a typical recipe, the highest theoretical concentration of thujone in absinthe produced from these wormwood samples would be less than 5 ppm.

Mike StapletonSt. Louis

2 comments:

Harold said...

From the original document - accepted without proper scrutiny by one journal (who I believe were also paid to allow open publication via PR Newsire services):

"The CVUA Karlsruhe received no external funding. D.N.-M. and T.A.B. own companies dealing with absinthe; however, no competing financial or other interest that might be affected by publication of the results contained in this study is declared"

1. Who are the CUVA Karlsruhe?
2. Who are D. N-M and T.A.B

The answer to 1. is an obscure veterinary & testing lab in Germany.

The answer to 2. is David Nathan- Maister and Ted Breaux. The former is an absinthe ecommerce baron and the latter is the manufacturer of Lucid Absinthe.

No competing interest? Let us look at Lucid's website:

"The resulting amount of thujone in Lucid is also comparable to many pre-ban absinthes. Lucid is completely authentic in every detail"

So I would suggest that given this demonstratable interest by at least one of the authors that this "science" is most likely a piece of self serving propoganda connected to commercial interests.

According to the FDA, alcoholic beverages like Lucid must be thujone-free pursuant to 21 CFR 172.510. This means <10ppm thujone.

Professor W. Arnold University of Kansas November 12, 2007 Boston Herald:

"Perhaps to raise the titillation for the current product, and to increase sales, they now claim that the “old absinthe” also had very little thujone in it! Supposedly the current drink has very little of several other terpenoids that were part of “old absinthe” because the current producers have missed the importance of (or intentionally avoided) “steam distillation” which was key to the manufacture of “old absinthe.” Steam distillation greatly affects the composition of the batchwise distillate. Any analogy to fractional distillation (as in whisky) is totally inappropriate with regard to 19th century absinthe manufacture. The toxicity of thujone, or any other toxic compound, depends upon both the amount and the time. How much and how long. There is ample evidence to indicate that high doses of thujone, camphor, fenchone (and related compounds) over a short time evoke convulsions and hallucinations in experimental animals. To the best of my knowledge there are no published studies on the long-term effect of 9 ppm thujone. It has been shown that thujone, pinene, and camphor, as well as alcohol itself, are all porphyrogenic"

Chris Perridas said...

Thank you, Harold.

This additional information is very interesting and shows that science is sometimes political.

I'll keep looking for more posts and letters on Absinthe.

-Chrispy.

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