Study Aging in Bourbon-Making

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Wayne Curtis, The New Science of Old Whiskey. Bourbon makers attempt to perfect a 2,000-year-old invention. The Atlantic, November 2013.
http://www.theatlantic.com/magaz ... old-whiskey/309522/

(a) Excerpt in the windows of print:

Most distillers I spoke with estimated that 60 or 70 percent of a bourbon’s flavor comes from the barrel. The Atlantic, November 2013.

One bourbon maker lashed five barrels on a trawler, where they were subjected to salt air, sun, and constant rocking.

(b) Quote:

(i) “It took a long while, but in the past few hundred years, discerning drinkers of spirits noticed that something interesting took place inside containers made of white oak, which were often used for liquids because oak is tightly grained, preventing leakage. Rum shipped from the West Indies to Boston and whiskey shipped from Kentucky to New Orleans were always better when they arrived than when they left.

“Today, barrels are central to the making of all manner of alcoholic beverages. Most winemakers use oak barrels that are toasted—that is, lightly browned on the inside through indirect heat. Liquor manufacturers more often use charred oak barrels, which are blackened with direct flame. Every spirit has its own barrel culture. Cognac tends to favor French oak (which is higher in tannins than American oak). A few rum makers, such as Zacapa Rum, from Guatemala, employ used sherry casks for finishing their product after it’s been aged in oak, adding flirtatious complications to the end result. Some American craft distillers, seeking to distinguish themselves from the major producers, have been experimenting with barrels made of alternative woods, including hickory and maple. Even some microbrewers are getting into the game, finishing beer in used bourbon casks.

“But bourbon has long been the main driver of the spirits-barrel industry, for one simple reason: to be labeled “bourbon,” a whiskey is required by law to have been aged in new, charred oak barrels, which impart far more flavor than barrels that have been used previously. (After aging bourbon, barrels are typically sold to makers of rum, scotch, or tequila for reuse.) Bourbon producers thus tend to focus more intently on barrels than other spirit makers do.

(ii) “This barrel flavoring takes place in part because alcohol is a solvent that gradually breaks down elements in the wood over time. White oak in particular has an abundance of appealing flavors, including vanilla, nuts, and coconut, as well as butterscotch notes from sugars in the wood, which are caramelized during charring.

“During the summer, heat increases pressure inside a barrel, and some liquor pushes itself through the char in the barrel’s wooden pores, enabling the carbon to filter out impurities. During the winter, the liquor moves in the reverse direction. The process is repeated with less vigor during the heating and cooling cycles of day and night.

“Cutting down aging time is particularly important for start-ups trying to get their spirits to market quickly. * * * (This is also why many start-up distillers launch with gin, vodka, or white whiskey, which can move from still to liquor store without delay.)

“Clay Risen, who writes about spirits for The New York Times and is the author of the forthcoming guide American Whiskey, Bourbon & Rye[, says:] ‘If you think of a clear, unaged distillate as a rough product, a first draft, barrels can be a sort of editing process—they can take the edge off, remove certain flavors, impart certain flavors over a relatively short period of time.’

(c) Note:
(a) The article mentions two distilleries (Buffalo Trace and Brown-Forman), as well as says, “The bourbon was bottled (which stops the aging process).”
(i) Buffalo Trace Distillery
http://en.wikipedia.org/wiki/Buffalo_Trace_Distillery
(located in Frankfort, Kentucky; Located on what the company claims was once an ancient buffalo crossing on the banks of the Kentucky River in Franklin County, the distillery is named after the American bison)
(ii) Brown-Forman
http://en.wikipedia.org/wiki/Brown-Forman
(one of the largest American-owned companies in the spirits and wine business; founded in 1870 by George Garvin Brown, a young pharmaceuticals salesman in Louisville, who had the then-novel idea of selling top-grade whiskey in sealed glass bottles; Headquarters Louisville)
(iii) Brown-Forman Corporation
http://www.ellenjaye.com/brown-forman.htm
(“The company originated in 1870 as a partnership between George Garvin Brown and his half-brother John Thompson Street. John (for whom his son Creel later named his own Bourbon ‘JTS Brown's Son’) left the partnership and eventually what had been his share became owned by George Forman, the company accountant. The name was then changed to Brown-Forman and has remained that way, even though Forman died only eleven years later and Brown bought his shares and the permission to use his name”)

(b) “Wooden-stave barrels first appeared millennia ago. In the first century AD, Pliny the Elder noted their widespread use in the foothills of the Alps.”
(i) stave (n; Middle English, back-formation from staves, plural of staf staff):
“any of the narrow strips of wood or narrow iron plates placed edge to edge to form the sides, covering, or lining of a vessel (as a barrel) or structure”  
http://www.merriam-webster.com/dictionary/stave

* For white oak, see Quercus alba
http://en.wikipedia.org/wiki/Quercus_alba
(native to eastern North America; Although called a white oak, it is very unusual to find an individual specimen with white bark; the usual color is a light gray)
(ii) Pliny the Elder
http://en.wikipedia.org/wiki/Pliny_the_Elder
(Gaius Plinius Secundus; 23-79 AD)

(c) “Barrels are thus remarkably stout and durable: if one tumbled off a ship’s gangway onto a wharf during loading, the impact of the fall was shared by all the staves, reducing the risk of breakage.”
(i) The noun “gangway” has several definition, one of which is “gangplank.”
http://www.merriam-webster.com/dictionary/gangway
(ii) gangplank (n; no etymology provided): “a movable bridge used in boarding or leaving a ship at a pier”
http://www.merriam-webster.com/dictionary/gangplank

Go to images.google.com to see what a gangplank looks like.
(iii) gangplank and gang.
Online Etymology Dictionary, undated.
http://www.etymonline.com/index.php?search=gangplank
(“from Old English gang ‘a going, journey, way, passage’”)

(d) “(This is also why many start-up distillers launch with gin, vodka, or white whiskey, which can move from still to liquor store without delay.)”
(i) Neither gin nor vodka is aged in a barrel.
(ii) Jason Pyle, What on earth is white whiskey?  
http://www.connosr.com/worldwhis ... h-is-white-whiskey/
("un-aged or lightly aged whiskey right off the still")

(e) “But while the increased wood-to-liquor ratio speeds the infusion of the wood flavors, that’s only part of the aging process. The other part occurs during oxidation, when air gets in through the barrel’s semi-porous wood and interacts with the spirit. Corn (bourbon is by law at least 51 percent corn) has long, complex, oily molecules, which give young bourbon its round and vegetal funk. During a chemical reaction called esterification, these chains break down and reconfigure, then react anew with the wood, adding depth and additional flavors. This oxidation process can’t be rushed with smaller barrels.”
(i) whisky
http://en.wikipedia.org/wiki/Whisk
(section 3.1 American whiskeys: Some types of whiskey listed in the United States federal regulations[27 CFR §5.22] are Bourbon whiskey, corn whiskey, malt whiskey, rye whiskey, rye malt whiskey and wheat whiskey; "Whiskies do not mature in the bottle, only in the cask, so the "age" of a whisky is only the time between distillation and bottling. This reflects how much the cask has interacted with the whisky, changing its chemical makeup and taste")

CFR stands for Code of Federal Regulations.
(ii) funk (n; probably ultimately from French dialect (Picard) funquer to give off smoke):
“a strong offensive smell”
http://www.merriam-webster.com/dictionary/funk
(iii) For esterification 酯化, see ester
http://en.wikipedia.org/wiki/Ester
(section 5 Preparation: Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester as the reaction product)

(f) “Black Swan, a four-year-old artisanal cooperage in Minnesota, is best known for its Honey Comb Barrels, which are, as the name suggests, honeycombed with shallow perforations on the inside. As with smaller barrels, the idea is to increase the surface area in contact with the whiskey, to speed up the aging process.”

cooperage (n)
http://www.merriam-webster.com/dictionary/cooperage
(g) “Cleveland Whiskey, a new brand, has a proprietary system involving ‘stainless-steel, pressure-capable tanks’ that its inventors claim can reduce the aging process from years to as little as six months. (The verdict’s still out.)”

Alan Greenblatt, How A Distillery Ages Bourbon In Days, Not Years. NPR, May 3, 2013 (blog)
http://www.npr.org/blogs/thesalt ... n-in-days-not-years
(Tom Lix's distillery in Cleveland; "Lix uses pressure to speed this up. He pours distillate into a stainless steel vat and throws cut-up pieces of barrel in after it. He wouldn't let me see his machinery — "intellectual property," he says — but it sounded something like an overloaded washing machine during the spin cycle”)