by Amy Stewart
Perhaps the most important influence on oak-aged spirits comes not from the tree but from the barrel makers, called coopers. They learned that coaxing oak staves into gentle curves required two things: time and heat. Freshly cut oak is given time to dry, which not only makes it easier to work with but also concentrates those important flavors. The staves are also lightly cooked to make them more pliable as they are shaped, and fire causes some of those flavors to caramelize, so that caramel, butterscotch, almond, toast, and warm, woodsy, smoke essences emerge.
Some whiskey barrels are entirely burned inside. No one knows how this started. It’s possible that a cooper accidentally lit a bigger fire than intended and decided to use the barrel anyway. Perhaps thrifty distillers burned the inside of old barrels used to store salted fish or meat to eliminate the flavor before filling it with whiskey. Regardless, the layer of charcoal filters and flavors the whiskey, particularly as the wood expands and contracts with changes in the weather. The Lincoln County process, made popular by Jack Daniel’s, takes this one step further by burning sugar-maple wood and filtering the whiskey through ten feet of charcoal before it ever reaches the barrel.
The coopers made one more contribution: after Prohibition, when it became necessary to enact new laws regulating the now-legal liquor industry, they helped ensure that bourbon (and other whiskey) would, as of July 1, 1936, have to be stored in charred new oak containers in order to claim the name. This, the newly formed Federal Alcohol Administration claimed, distinguished “American-style whiskey” from Canadian products, which possessed a milder flavor owing to the fact that they were distilled at a higher proof and stored in reused cooperage. Although the law has gone through some revisions and challenges, the requirement to use new barrels for each batch of bourbon has been in place continuously, with only a brief respite from 1941 to 1945 because of wartime shortages.
One result of this quirk in American law is that there are an abundance of used bourbon barrels for sale. Scotch distillers love them: they employ a blend of used bourbon, port, and sherry barrels to give a nice complexity to their fine spirits. In fact, the Laphroaig distillery boasts that it uses exclusively Maker’s Mark barrels. Used bourbon casks are also used to age rum and other whiskey blends.
The particular way that oak absorbs and releases a spirit has led to a great deal of experimentation. Coopers can construct barrels with trees grown in a particular climate or soil type, which can affect the tightness of the grain and the levels of tannins and flavor molecules. They can even build a barrel of sapwood as opposed to the denser, less absorbent heartwood. Distillers are starting to market whiskey aged in a barrel from one part of the tree or another, knowing that connoisseurs will literally lap it up.
A FIELD GUIDE TO OAK
Q. alba: American white oak; grown in eastern United States, used for whiskey and wine.
Q. garryana: Oregon oak, used by some Pacific Northwest wineries and distillers. More comparable to French oak.
Q. mongolica: Japanese oak, popular among Japanese distillers.
Q. petraea: Sessile or French oak; grown in Vosges and Allier. Preferred by winemakers.
Q. pyrenaica: Portuguese oak, often used for port, Madeira, and sherry.
Q. robur: European oak; grown in Limosin. Preferred for Cognac and Armagnac.
BUGS in BOOZE: alkermes scale
--- Kermes vermilio ---
Scale is a tiny insect that latches onto a branch and hides under its protective shell. This particular species preys on Q. coccifera, a species of oak tree in the Mediterranean. The females suck down tree sap until they are as big and round as a tick, secreting a crimson gummy exudate. At some point, in the course of scraping scale off the tree, somebody must have noticed that the red pigment stained clothing and hands. It was certainly well known to the Greek physician Dioscorides, who wrote an odd entry in De Materia Medica (50–70 AD) about little insects that grow on oaks and are “similar in shape to a little snail, which the women there gather by mouth.” Dioscorides was known to get a few things wrong; it’s unlikely that women actually picked bugs off trees by mouth when a stick would do. Even using a stick was tricky: the bugs had to be removed more or less intact, then killed (usually by steaming them or dropping them in vinegar), and then dried and taken to market, where they would be sold as a fabric dye.
Like most strange and unusual things in the natural world, the red pigment found its way into Italian liqueurs. The recipe can be traced back to an eighth-century medicinal tonic called confectio alchermes that called for taking a length of silk that had been dyed red with the insect, soaking it in apple juice and rose water to extract the dye, and adding extraordinarily rare spices that included ambergris (sperm whale bile), gold flakes, crushed pearls, aloe, and cinnamon. Over time, the recipe changed to include more familiar flavors like cloves, nutmeg, vanilla, and citrus, and the red dye came from cochineal, another insect-based dye newly arrived from the Americas. It was brighter in color and easier to harvest.
By the nineteenth century, the bright red liqueur known as alkermes (or alchermes) was made by several Italian distillers as a digestif, not a medicine. It also became the flavoring for a layered spongecake desert called zuppa inglese. A modern version of the liqueur is still available in Italy and can be found in specialty Italian food shops. The ancient Santa Maria Novella pharmacy in Florence carries their own formulation. Unfortunately, alkermes made with actual kermes scale are a thing of the past; the only red insect-based food dye allowed in the European Union is E120, the cochineal scale.
GRAPES
Vitis vinifera
vitaceae (grape family)
Quick: name a fruit that is made into alcohol. What comes to mind first? Probably grapes. But believe it or not, the very existence of grapes is surprisingly unlikely. The fossil record shows that grapes were established in Asia, Europe, and the Americas fifty million years ago. But when the last ice age, the Pleistocene epoch, began about 2.5 million years ago, vast sheets of ice covered much of the grape’s range and nearly drove it to extinction. The vines that managed to pass the time in unfrozen corners of the world were the only ones left for early humans to encounter. It’s entirely possible that the grapes that flourished before the ice age were far more diverse and interesting than what we grow today.
To make the success of the grape even more improbable, those early vines would have yielded nothing like the abundant clusters of sweet, marble-sized fruit we know today. The grapevines that survived the ice age were dioecious, meaning that each plant was either male or female. The vines depended upon insects to transport their pollen, and if a female was too far away from a male, it simply wouldn’t happen. The fruit from these couplings was unpredictable as well. Grapevines, like apples, can produce offspring whose fruit will be quite unlike that of its parents. Some of those grapes would have been small, bitter, and full of unpalatable seeds.
So what happened to improve the grape’s prospects? A mutation that changed the plant’s sexual orientation. In dioecious plants, the females are female because a gene suppresses the formation of male anatomy and vice versa. But sometimes those genes go awry and nature creates a hermaphrodite. The vines that resulted from those mutations had both male and female anatomy on the same plant. Because the pollen didn’t have as far to travel, the vines produced more abundant fruit. The earliest agrarians might not have understood why certain vines were more prolific, but they would have selected them to grow in their settlements. That selection process began about eight thousand years ago, and from there, it was simply a matter of choosing the tastiest fruit and taking cuttings to get a genetic clone. Fortunately, pottery was also being invented around the same time, leading to the happy circumstance of crushed fruit stored in a container long enough for wild yeast to find it.
One more lucky break made wine making possible. A particular species of wild yeast that feeds on the exudates of oak tree bark managed to crawl into early wine vats around five thousand years ago and do a particula
rly good job of fermentation. There would have been other yeasts living naturally on grape skins, but they would not have been nearly as well suited to the job. But somehow, oak yeast got into the mix.
How did this happen? Scientists have a few theories. It might be that grapevines occasionally climbed up an oak tree and picked up the yeast. It’s also possible that people gathered acorns and grapes at the same time, commingling the microorganisms on each, or that insects picked up the yeast on an oak tree and carried it to a grapevine because it was attracted to the rising sugar in the fruit. However it happened, that yeast species, Saccharomyces cerevisiae, found its way into wine somehow. Today it is an entirely domesticated creature, rarely found in the wild and widely bred into specialized strains that are used around the world to make bread rise and to ferment wine and beer.
NOBLE ROT
The fungus Botrytis cinerea inflicts grapes with a nasty disease called botrytis bunch rot. If it attacks in early spring, it can make leaves wither and flowers drop off the vine. On young, immature fruit it forms nasty brown lesions that turn black and split the fruit apart. The rotten grapes, filled with fungus, drop to the ground and wait for an opportunity to reinfect the plant. Botanists refer to the dead, infested fruit as mummies.
But sometimes, under just the right weather conditions, botrytis hits late in the season and causes something remarkable to happen. If temperatures stay between 68 and 78 degrees Fahrenheit, and if the humidity is very high, and if the grapes are just ripe enough, they are infected but not ruined by the fungus. Then, in order for the magic to happen, the humidity must drop to about 60 percent. In other words, it needs to be cool, and rain, and then stop raining, as the grapes are getting ripe.
If all this happens at just the right time, the fungus will dehydrate the grape, concentrate the sugars, but not destroy it. That’s called noble rot, and it’s responsible for some of the great botrytized wines of the world. Sauternes, made in a particular region in Bordeaux with Sémillon, Sauvignon Blanc, and muscadelle grapes, are the finest expression of what noble rot can do to a grape. They are sweet but faintly spicy, with a distinctive honey and raisin flavor. The wines can be expensive: noble rot is unpredictable, each grape must be picked individually by hand, and an entire vine might only yield the equivalent of a single glass of wine. Botrytized wines also come from Germany, Italy, Hungary, and other wine-growing regions around the world, but because the fungus is so unpredictable and dangerous, few winemakers are willing to take the risk and allow it to colonize their vines.
WARNING: DO NOT ADD WATER
During Prohibition, enterprising California grape growers kept themselves in business by selling “fruit bricks”—blocks of dried, compressed grapes that were packaged with wine-making yeast. A label warned purchasers not to dissolve the fruit brick in warm water and add the yeast packet, as this would result in fermentation and the creation of alcohol, which was illegal.
the first wine
Archeologist Patrick McGovern has analyzed ancient pottery fragments around the world and found evidence of wine making dating back six thousand years in the Middle East. A UCLA team uncovered a complete wine production facility in Armenia from the same period. McGovern also detected possible grape residue in pottery fragments from 7000 BC in China. The only people who did not develop a strong wine-making tradition with their local grapes were Native Americans—or if they did, they’ve hidden the evidence very well. South American Indians in particular made alcohol from corn, agave, honey, cactus fruit, seedpods, and bark, but they rarely, if ever, threw grapes into the mix.
Over time, the Egyptians, Greeks, and Romans became the world’s most sophisticated vintners. Many early scientific advances slipped into oblivion during the Middle Ages, but wine-making technology survived, thanks to the efforts of monks and the deep associations between wine and religion. By the 1500s, vineyards were beginning to transition from church enterprises to private operations, often run by nobility. During the next few centuries, the British managed to forget they were at war with France often enough to purchase enormous quantities of their enemies’ fine wines. Clearly, a robust European wine market was already in place as colonists were arriving in the New World.
the invention of brandy
By that time, a tradition of distilling wine into brandy had emerged as well. Spanish and Italian writings from the thirteenth century show that wine was being boiled into some kind of strong spirit. The Dutch gave it the name brandewijn, or “burnt wine,” which was shortened to “brandy.” Dutch traders set up stills in ports where wine was made, particularly if the wine was mediocre and would be more profitable in the form of brandy. One such place was France’s Cognac region. The white wines made in the area were not terrible; they were just bland. The Dutch hoped to reduce shipping costs by distilling them into a high-proof spirit that would later be mixed with water as a substitute for wine. Sometimes, in the confusion and chaos of a busy port, those spirits would sit in a barrel longer than intended. The result? Rich, complex, aged Cognac. It later became clear that even vineyard waste could be fermented: crushed skins, stems, and seeds all went back into the fermentation tank to make a high-proof spirit like grappa.
While grape brandies and eaux-de-vie were coming into their own around Europe, Spanish and Portuguese winemakers noticed that the British had a taste for sweet wines fortified with brandy. Adding extra alcohol to wine was an easy way to stop the fermentation process—yeast can’t live in a higher-proof solution—but it also helps a different kind of yeast to survive. In the Jerez region in southern Spain, white wine was traditionally aged in casks that were only partially full. A particular strain of S. cerevisiae yeast colonized the casks and formed a thick skin over the wine. The Spanish call it flor; scientists call it velum. Unlike other strains of yeast, the flor actually prefers a higher alcohol content of around 15 percent, so winemakers would fortify the wine to keep the yeast alive.
These wines—which the British called sherry, possibly a corruption of Jerez—are said to be biologically aged because the yeast changes the flavor over time. Adding to sherry’s complexity is the use of the solera system for aging. The barrels are stacked four high, with finished sherry coming only from the bottom barrel. It is refilled by sherry from a barrel above it, which is then refilled from the barrel above that, and so on. New wine is only added to the top barrel. Some soleras have been in continual operation for over two hundred years, giving the finished product extraordinary depth and flavor.
Other regions developed their own fortified wines. Portuguese winemakers added brandy to half-fermented wine to stop the yeast from eating all the sugar. After a few years in tanks or barrels, the raisiny-sweet result is port. Madeira, also from Portugal, is made in a similar manner, usually with white wine grapes, and then exposed to air and subjected to the kinds of temperature extremes that early barrels would have encountered on long ocean voyages. This deliberate abuse gives it its oxidized, dried fruit flavor and means that it ages well and remains drinkable for up to a year after it’s been opened. Italy’s Marsala is similarly fortified and aged—and so it goes, in wine-making regions around the world.
Another centuries-old European tradition—that of flavoring wine with herbs and fruit—led to the invention of vermouths and aperitif wines, also called aromatized or fortified wines. They might have originally been intended as medicine—a wine infused with wormwood, quinine, gentian, or coca leaves would have represented an attempt to treat intestinal worms, malaria, indigestion, or listlessness, respectively—but by the late nineteenth century they had become respectable drinks in their own right. Vermouth is made with white wine (red vermouth is not made with red wine, but white wine sweetened and colored with caramel) and fortified slightly with brandy or eau-de-vie, bringing the alcohol content to about 16 percent.
VERMOUTH COCKTAIL
This classic cocktail is a template for experimentation with aromatized wines. Mixing Punt e Mes and Bonal Gentiane Quina, for instance, makes for a
remarkably good drink. And Lillet blends well with almost anything.
1 ounce dry white vermouth
1 ounce sweet red vermouth
Dash of Angostura bitters
Dash of orange bitters
Lemon peel
Soda water (optional)
Shake the white and red vermouth and bitters over ice and strain into a cocktail glass, or serve over ice topped with soda water. Garnish with the lemon peel.
A FIELD GUIDE to FORTIFIED WINES
Fortified wines are wines with higher-proof alcohol added. The most famous are:
Madeira: Oxidized Portuguese wine fortified with neutral grape spirit.
Marsala: Fortified Italian wine made in the Marsala region.
Muscatel or Moscatel: Sweet, fortified muscat wine produced mostly in Portugal.
Port: Portuguese wine fortified with grape spirit before fermentation is over, leaving residual sugars in the blend. (In the United States, such wine made anywhere in the world can be called port, but only the Portuguese version can carry the label “porto.”)
Sherry: Spanish white wine mixed with brandy after fermentation is complete.
Vins doux naturels: Sweet, fortified French wine, often made from muscat grapes.
