Angels’ share challenge

Analytical and Bioanalytical Chemistry, Nov 2013

Reinhard Meusinger

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Angels’ share challenge

Reinhard Meusinger 0 ) NMR Abteilung, FB Chemie, Technische Universitt Darmstadt , Petersenstr. 22, 64287 Darmstadt, Germany We would like to invite you to participate in the Analytical Challenge, a series of puzzles to entertain and challenge our readers. This special feature of Analytical and Bioanalytical Chemistry (ABC) has established itself as a truly unique quiz series, with a new scientific puzzle published every other month. Readers can access the complete collection of published problems with their solutions on the ABC homepage at http://www.springer.com/abc. Test your knowledge and tease your wits in diverse areas of analytical and bioanalytical chemistry by viewing this collection. In this challenge, flavorants are the topic. And please note that there is a prize to be won (a Springer book of your choice up to a value of 100). Please read on - Meet the angels share challenge The small portion of wine or distilled spirit that is lost during long aging in wood barrels is known as the Angels share (if this nip is larger than two percent per year, the alertness of the tax collectors will awaken). Many flavoring compounds are extracted from the wood of the barrels during this time. In fact, several hundred flavorants have been detected in these complex beverages, including a gamut of alcohols, carbonyl compounds, carboxylic acids and their esters, terpenes, nitrogen-containing and sulfur-containing compounds, tannins and other polyphenolic compounds, and oxygencontaining heterocyclic compounds [1]. In this challenge we are looking for such a compound which occurs in whiskies, cognac, rum, and also old wine. The complexity of this subject is grand, which is why this challenge will be limited to whisky. The flavor and color of whisky arises due to three reasons: the distillation, the cask maturing, and additives. During distillation, the flavor develops in part because of the presence of fermentation products, for example acetals, ketones, esters or aldehydes, and higher alcohols. Most of these compounds contribute to the hangover (veisalgia) and will not be given closer attention here. The additional flavor and color of whisky depends strongly on local regulations. For instance, a Scotch whisky may contain no additives other than the caramel coloring (E150a). Last, the presence of our flavorant in whisky is because of the aging process. Laws in several jurisdictions require that whisk(e)y must be aged in wood barrels. Similar regulations exist for brandy, sherry, and cognac. In addition to the length of aging, the volume of the barrels and their storage location, the type of wood and its provenance also play an important role in the quality of the end product. The type of the wood used for barrels will be kept a secret in this challenge. This tree is a symbol of strength and endurance and a national tree of many countries. In Greek mythology it was sacred to Zeus and in Norse mythology it was sacred to Thor, and a legend goes that the Christianization of Germany was marked by the felling of this sacred tree by an Anglo-Saxon missionary in 723. Today, both the common name and the botanical (Latin) name of this tree features in the trivial names of our compound. The barrels for aging alcoholic beverages are made from European and American trees. The choice between these two kinds of tree is especially important for wine producers. For maturing of whisk(e)y, different rules are prescribed by law. As an example, the straight whiskey must be stored in the United States for at least two years in new, charred wood containers; Bottled in Bond Bourbon whiskey liquor must age for four years whereas all Scotch whisky must be aged in wood barrels for at least three years and one day [2]. Therefore, it seems that only the fanciers of fresh distilled whisk(e)y, named new spirit, moonshine, or poitin underestimate the value of our flavor compound. All other consumers enjoy spirits matured in wood casks. Misleadingly, the maturing of Scotch whisky in a new cask does not mean the use of a fresh unused cask. In Scotland, the first fill typically describes maturing in an American cask formerly used to mature bourbon whiskey. Recently, a new trend, the so-called finishing has gained in popularity with the product known as double matured or wood-finished. Here, the spirit spends further time in a second cask, usually one that has been used to mature fortified wine, sherry, port wine, Madeira, or even standard wines. However, this may still not be the end of the life of a wood cask. For example, the pepper mash used to make Tabasco sauce is aged for three years in used whiskey barrels (Fig. 1). From the scientific literature, it appears that our compound was first reported at the end of the 1960s. For convenience, it was first christened after the peak number in the gas chromatogram of red wine flavorants. Shortly after the first description it was found that four possible stereoisomers can exist, and in the aft (...truncated)


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Reinhard Meusinger. Angels’ share challenge, Analytical and Bioanalytical Chemistry, 2013, pp. 8685-8689, Volume 405, Issue 27, DOI: 10.1007/s00216-013-7301-7