Public Release:  'Chemistry of the Bar' symposium focuses on New Orleans' Hurricane Cocktail and more

American Chemical Society

NEW ORLEANS, April 9, 2013 -- Call their taste and effects appealing or appalling, no matter. In a city that claims credit for invention of the cocktail, the Hurricane, Sazerac, Pimm's Cup, Bayou Bash, Hand Grenade, Ramos Gin Fizz and other concoctions are the spirits of the French Quarter and its most famous thoroughfare, which happens to be named Bourbon Street.

The scientific secrets of alcoholic beverages in the Crescent City and other venues will get a thorough shaking and stirring in a symposium titled "The Chemistry of the Bar" today during the 245th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society.

Abstracts on the following topics appear below:

  • Chemistry of the Hurricane cocktail.
  • The chemistry of that sweet almond-flavored liquor called Amaretto.
  • Single-hop India pale ales.
  • The unseen plumbing in taverns that brings beer to the glass.
  • How aging affects the taste and aroma of bourbon.
  • The chemistry and anatomy of the hangover.

One of the speakers, Neil C. Da Costa, Ph.D., focused on what may be New Orleans' most famous mixed drink, the pink stuff that tourists sip from disposable plastic cups while strolling down Bourbon Street. (New Orleans laws permit drinking in public and leaving a bar with a drink, but prohibit public drinking from glass or metal containers.)

"The Hurricane is an ideal topic for this symposium," Da Costa explained. He is with International Flavors & Fragrances, Inc., in Union Beach, N.J. "It is one of New Orleans' signature cocktails, and its origins echo the city's vibrant history. The drink originated in the World War II era, in the 1940s. Scotch, bourbon and other whiskeys were hard to get. But there was a big surplus of rum. Local distributors forced bars to buy up to 50 cases of rum in order to get one case of whiskey. One bar owner, Pat O'Brien, came up with the recipe for a fruity rum drink and served it in a glass shaped like a hurricane lamp. The name stuck."

Da Costa's presentation goes beyond the history to focus on the Hurricane's key ingredients, their chemical compositions and interactions and sensory evaluations of the resulting beverage.

The Hurricane is mainly a light and dark rum cocktail, Da Costa said, noting that some recipes also call for generous portions of gin or vodka. Besides the spirits, a typical Hurricane contains lime juice, orange juice, passion fruit syrup, grenadine (which provides the red color and added sweetness) and a simple sugar syrup.

"For the Hurricane's fruity aroma, terpene compounds such as limonene and citral play a crucial role, giving a fresh citrus note. In addition, 'sweet' compound notes from the rum and sugar break down, such as various esters, vanillin, 5-methylfurfural and 5-hydroxymethylfurfural. These combine to essentially give the sweet fruity aroma of the cocktail. Of course the strong aroma of aqueous ethanol is always appealing."

Freshness of the ingredients is the key to making the best Hurricane, Da Costa said, just as freshness affects the taste of the Bloody Mary and other cocktails with fruit or vegetable components. And Hurricanes made from powdered or bottled mixes pale in comparison to those made from scratch. Does premium or boutique rum improve the taste?

"Using pricey rum is probably a waste of money for most consumers," Da Costa said. "The Hurricane is an intensely sweet drink, with complex flavors, and that tends to mask the taste of the liquor. If you're going to drink one, go for the cheap bar or well rum."

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Here are abstracts of other presentations in the symposium:

Abstracts

Chemistry of Amaretto

Jerry A Zweigenbaum, Agilent Technologies
Phone: 302-636-3661
E-mail: j_zweigenbaum@agilent.com

Amaretto is a sweet almond flavored liquor made using varying ingredients that can include herbs, botanicals, apricot kerenal and almond essence. Amaretto can be enjoyed on its own or as a digestif. Its name comes from the Italian amaro meaning "bitter" or slightly bitter and is associated with the flavor of bitter almond. Its origin is found in the Italian town of Sarrono and legend has it was a gift of brandy soaked in apricot pits. Apricot pits, like almond kernels, are rich in the diglycoside amygdalin, which is found in the seeds of the trees Prunus dulcis. Amygdalin is composed of two glucose moieties a cyanide group and a benzene ring. Upon de-glycosylation, amygdalin forms benzaldehyde; the key component of bitter almond taste and aroma. Herein, the chemical composition of 6 different brands of amaretto liqueur were evaluated for amygladin down to trace levels using a UHPLC (ESI)-MS/MS. In addition, UHPLC-Q TOF MS/MS was used to profile the non-volatile compounds found in ethanolic almond kernel extracts and this profile was compared to that found in the different amarettos. Finally, headspace GC/MS was used to characterize the volatile components of the 6 liqueurs and ethanolic extracts of almond kernels. From these analyses the chemistry of amaretto will be described.

Decoding the taste of wine by combining analytical chemistry and sensory evaluation

Andreas Dunkel, Technical University of Munich
Phone: 00498161712903
E-mail: andreas.dunkel@tum.de

The sensory impressions perceived during wine consumption result from the simultaneous stimulation of our senses. Although a wine is initially assessed by its visual appearance and bouquet, the bitter taste and the astringent oral sensation are important contributors to the sensory quality of wines. Aimed at identifying the key molecules driving the attractive taste of a red wine, a screening technique called taste dilution analysis was applied to a red wine and a total number of 37 compounds was isolated and characterized. Quantitative studies in combination with taste reconstitution and omission experiments demonstrated that besides the low-molecular weight compounds a structurally undefined high molecular weight fraction was important for the overall astringency. Gel permeation chromatography, alkaline treatment, acidic hydrolysis, and thiolytic depolymerization, respectively, followed by compositional analysis demonstrated these taste-active polymers to be made up by diversely substituted flavan-3-ol derivatives, carbohydrates, phenylpropenoic acids, hydroxylated benzoic acids, and anthocyanins.

Quality assessment of Polish raw spirits using GC × GC-TOFMS and electronic nose

Tomasz Dymerski, Gdansk University of Technology
Phone: +48 58 348 64 11
E-mail: tomasz.dymerski@gmail.com

Quality is a very important attribute of every alcoholic beverage. To provide high quality of these products, the quality of intermediate materials has to be ensured as well. The purpose of this work was the identification of volatiles present in the headspace of Polish raw spirits. Volatile compounds were isolated by headspace solid-phase microextraction (HS-SPME). Analyses were performed by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF-MS). Over 200 compounds were identified. Some of them were selected as quality markers of Polish raw spirits. The second aim of this work was the characterization of the volatile fraction of Polish raw spirits using a prototype electronic nose equipped with six non-selective semiconductor sensors. For data acquisition and processing, an in-house written program based on principal component analysis (PCA) was utilized. This study has proven that the prototype electronic nose can distinguish.

Beer-omics: Differential analysis of single-hop India pale ales by q-TOF MS and NMR

Christine A Hughey, James Madison University
Phone: 540-568-6633
E-mail: hugheyca@jmu.edu

Metabolomics of food is an emerging field that combines the disciplines of food science and nutrition with advances in bioinformatics and untargeted profiling technologies. Here we use quadrupole time of flight mass spectrometry (q-TOF MS) and nuclear magnetic resonance (NMR) spectroscopy to profile single-hop India pale ales (IPAs) produced by the Mikkeller brewery in 2010 and 2011. The brewer kept all the parameters the same and varied only the hop used. Differential analysis (e.g., PCA and hierarchical clustering) by q-TOF MS revealed significant compositional differences between the 2010 and 2011 batches. These compositional differences were used to build a class prediction model that successfully identified the hop in unknown single-hop IPAs 100% of the time. We also conducted 13C-natural abundance HMQC experiments on a 600 MHz NMR in order to investigate how NMR may provide complementary metabolite profiling information to q-TOF MS.

Volatile compounds of aromatic cocktail bitters: A HS-SPME-GC-MS analysis

Arielle J Johnson, University of California, Davis
Phone: 5307549066
E-mail: ajohnson@ucdavis.edu

Aromatic cocktail bitters, concentrated alcoholic tinctures of herbs, spices, barks, roots, and other other highly-flavored plant material, are an essential component of many mixed drinks. Despite their historical and culinary importance and recent cultural and commercial resurgence, there is little to no data available on their volatile components, which would allow for a broader understanding of the flavor chemistry of mixed drinks, and could assist in the development of further styles of bitters. In this experiment, ten cocktail bitters including historical and modern styles were analyzed semiquantitatively in triplicate by Headspace-Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Each bitter contained, on average, 34 compounds and each compound was found in a mean of 2.5 bitters. Overall, 134 different volatile compounds were identified, including 11 aliphatic aldehydes, 17 esters, 28 sesquiterpenoids, 42 monoterpenoids and 25 aromatic compounds including 14 phenylpropenes.

Early aging: The characteristics given to bourbon in the early stages of White Oak aging

Scott Varney, Transylvania University
Phone: 606-854-4772
E-mail: msvarney13@transy.edu

In the creation of commercial bourbons and whiskeys, the aging process in a usually charred White Oak barrel has the ability to add many flavors and characteristics to the alcohol solution before being bottled and sold to consumers. In this process many of these alcohol solutions are given additional characteristics such as smoky flavors, a distinguishable color, and other traits that help make the samples more desirable. In our research work, we have taken ethanol solutions that range from 45%-65% and aged them with a variety of American and French White Oak wood chips that had different charring preparations. Through analysis with a GC/MS and a UV/Vis Spectrometer, we have been able to determine the initial entrance of chemicals, their concentration changes over time, and the development of a time interval system for specific chemicals as they age our solutions.

Chemical engineering in the tavern

Jaime Jurado, Susquehanna Brewing Company
Phone: 2102404731
E-mail: jjurado@sbcbeer.com

Much of the world's social history has been framed around the inn, pub, or as the Romans called them, the tabernae. We often take for granted that the beer in the glass came from a keg, and that the requirements for gentle transport of the sensitive liquid are similar to what one would expect from many costlier materials: the product is shear-sensitive, highly sensitive to bacterial infection, and carbonation levels and target dispense temperature in the beer must be maintained. The customer demands the beer to be served in a tight temperature range, with a nice head of foam. After a quick overview of the scope of draft beer sales in the hospitality industry, we will explore, as chemists and chemical engineers, design aspects of beer draft dispense systems, and look at cleaning and dispense parameters in a framework made familiar in the undergraduate curricula. The presentation includes a simple kinetics-based model and closes with a brief look at analytical calculations related to carbonation and bubbles from a Stefan-Maxwell perspective.

Discovery of adulterated alcoholic beverages in Kazakhstan using optimized method based on solid-phase microextraction and GC-MS

Bulat Kenessov, al-Farabi Kazakh National University
Phone: 7 727 2921374
E-mail: bkenesov@mail.ru

Adulteration of alcoholic beverages in Kazakhstan and many developing countries around the world is a wide-spread problem causing health risks to population. For law enforcement agencies, forensic examination of actual products is generally the only tool to obtain proper evidences against responsible individuals and companies. Solid-phase microextraction (SPME) in combination with GC-MS was proven to be efficient and fast method for characterization of alcoholic beverages. In this research, SPME-GC-MS-based method was optimized for detection of a highest possible number of compounds present in cognacs, wines and vodkas. Synchronous SIM/Scan mode of MS detector was utilized for simultaneous detection of abundant constituents along with trace compounds. Optimized method was applied for examination of samples taken from various locations in Kazakhstan. Principal component analysis method was utilized to differentiate adulterated and non-adulterated samples. Research was conducted under ISTC (International Science and Technology Center) K-1983 project funded by US Department of State.

Historical perspective and modern day flavor significance of oak wood aging of distilled spirits

Elizabeth R Genthner, University of Illinois
Phone: 217-333-1642
E-mail: genthne1@illinois.edu

Wood barrel aging of fermented and distilled beverages has been in use for centuries. It is currently accepted that the wooden barrel was invented by the Celts around 900 B.C while inhabiting the Danube River area in central Europe. By noting the obvious flaws of clay pots for wine storage; the Celts, who were both talented wood-workers and metallurgists, created the first wooden barrel. After migrating to the Irish Isles, where grape cultivation was difficult, the first whiskey was born by the oak barrel aging of the distillate of fermented grains. Since then the practice of oak wood aging has had a tremendous impact on spirits manufacturing and has made its way around the world; notably as bourbon in the United States, tequila in Mexico, rum in the Caribbean, and many other regionally specific spirits. Significant strides have been made to characterize the desirable flavors imparted by oak. Some of the top contributing aroma compounds include: guaiacols (smoky), cresols (barn, medical), eugenols (clove), furanones (caramel), lactones (coconut, peach) and vanillin (vanilla). One of the most important discoveries was that of cis and trans-methyl octalactone, so called whiskey lactones. Both compounds are highly concentrated in oak wood as well as oak aged spirits and elicit a coconut-like odor. The above mentioned compounds, as well as some less-studied odorants that impart wood-like or incense-like notes, will be discussed.

Chemistry of the Hurricane cocktail

Neil C. Da Costa, International Flavors & Fragrances Inc.
Phone: 732-335-2110
E-mail: neil.dacosta@iff.com

The Hurricane cocktail is one of two famous signature cocktails of New Orleans, Louisiana; the other being the Sazarac. It was invented in the 1940's at Pat O'Brien's Bar to reputedly get rid of surplus rum the local distributors forced him to buy when whisky was scarce. Its main ingredients are light and dark rum respectively, lime juice and or orange juice, plus passionfruit juice. Additional components like gin, vodka, almond liqueur, triple sec, grapefruit juice, sugar syrup and grenadine have been added as the recipe developed over the years as well as variant recipes.

This presentation will describe the flavor volatile compositions of the key and minor ingredients. In addition the role these volatiles play in the overall flavor and drinking experience.

Chemistry and anatomy of a hangover

Alyson E Mitchell, University of California Davis
Phone: 530-304-6618
E-mail: aemitchell@ucdavis.edu

Most American's will experience a hangover at least once in their lifetime. The term hangover refers to a collection of unpleasant and painful symptoms that can develop after excessive alcohol intake. Headache, body aches, weakness, nausea are all common symptoms of a hangover. Acute alcohol intoxication can affect the liver, the brain, gastrointestinal system and the central nervous system. Alcohol is metabolized in the liver by two enzymes. Alcohol dehydrogenase oxidizes ethanol to form acetaldehyde; a reactive compound that quickly forms toxic free radicals. Acetaldehyde is further metabolized to the non-toxic acetic acid by the enzyme aldehyde dehydrogenase. Acetaldehyde produces many of the symptoms associated with a hangover. However, different types of alcohol can cause different hangover symptoms to manifest. Drinks with higher concentrations of congeners generally result in more pronounced symptoms. Red wines and dark liquors such as bourbon, brandy and whiskey contain higher levels of congeners than white wines and clear liquors such as vodka. Carbonation speeds the absorption of alcohol. Herein a general discussion of the biochemical effects of alcohol consumption and the anatomy of the resulting hangover will be discussed.

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