The Wheat of Virgin Spaces

As part of an unrelated project, I recently had the opportunity to have several dozen absinthes, some vintage, some modern, analysed for methanol content. The overall results were that the quality of the alcohol in most vintage absinthes was surprisingly good, on a par with modern absinthes. Most of the samples tested in the range 5-20mg methanol per 100ml of ethanol. This included btw, several different bottles from the 1914 cache. 

There was only one outlier, a bottle of green absinthe dated 1953, from clandestine production in the Val-de-Travers. I obtained this bottle several years ago from a very reliable source in Couvet, and it’s to date the only “vintage” clandestine absinthe I’ve ever found. Over the years, I gave (not sold) a few samples to friends here on the forum. The absinthe had a markedly funky taste, which I ascribed to a distillation pushed too hard, as is often the case with clandestine La Bleues. It didn’t specifically occur to me that the origin of the alcohol could be a problem, as La Bleue, certainly from the late 1970’s, was routinely made with highly rectified spirit purchased from official Swiss sources. I assumed the same situation had applied in the 1950’s.

So it was a surprise, to put it mildly, to find that the methanol content of this ‘53 Verte was off the scale - 3143mg/100ml - more than three times the EU limit of 1000mg/100ml, and more than 60 times the defacto commercial standard of 50mg/100ml. This level of methanol is not possible simply from poorly rectified wine spirits - it indicates without doubt that this absinthe was made from denatured alcohol. Denatured alcohol is industrial alcohol which has been rendered unfit for human consumption, so as to escape the usual taxes on drinking alcohol. The most common form is methylated spirits, which is dosed with 5% methanol (and usually other substances as well). Because it’s virtually tax free as opposed to highly taxed food-grade alcohol it’s always been attractive to moonshiners, and periodically there are casualties from its consumption, usually in Russia, Eastern Europe and the Third World. There are absolutely no cases documented in the scientific literature of methanol poisoning in Switzerland.

It’s important to note that the level of methanol in this sample - 1.6% - while very worryingly high, is not quite at a toxic level. Paine and Davan, in their 2001 paper, concluded that if an adult consumed 4×25-ml of a drink containing 40% vol of alcohol over a period of 2 h, the maximum tolerable concentration of methanol in such a drink would be 2%/vol. Fortunately the concentration in this absinthe was 20% below this level, the samples I sent out were very small, and the absinthe would have been diluted further with water before drinking; so no harm could be done, even in theory. I drank two or three glasses myself from the bottle over the years with no ill-effects. Nonetheless, this is a sobering reminder that non-commercial alcohol should always be treated with extreme caution.