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Other Bourbon/American Classics:
Copper |
Charcoal
by Lew Bryson
When you visit a bourbon distillery, there are two very important things to see, by way of a compressed whiskey lifetime. Take a look at the fill room, where the new, raw spirit is introduced to
the barrels. It's true 'water of life' at this point: crystal-clear, quick-running, transparent. Then take
a walk that can be as short as 30 yards in some distilleries, the distance to the dump trough where the finished whiskey is poured out of the barrels. The smell of the aged whiskey is rich and heavy in the air, the amber spirit rushes from the bunghole, and there's a delicious thrill to watching that little liquor river flow down the trough.
Your 30-yard walk has carried you through four to ten years-or more-and the water-clear spirit has become bourbon. Ask the man at the bar who drinks the whiskey what made the difference, and he'll probably tell you it's the age. Ask the cooper who makes the barrel, and he might tell you it's
the wood and the char. Ask the distiller who makes the whiskey and watches it through all those years, and he'll probably tell you the whole story. They're all right. But it's the char that is perhaps the most complicated and mystical part, and the thing that makes
this spirit bourbon.
Char makes it bourbon? Think about it. Corn is part of bourbon, but it's also part of corn whiskey. The small grains are common to a lot of spirits. There are plenty of numbers and times in the definition of bourbon, but those are details. Even the white oak barrels are used in aging other spirits.
But what is unique about bourbon is that every drop must be aged in new, charred white oak barrels. There's something in that charred layer of white oak that makes bourbon. Put corn spirit together with the char, and you get magic. Fact is, a lot of the flavor in bourbon comes right out of that blackened layer of wood. How much? "We say anywhere from 60 to 70, maybe 80%," said Lincoln Henderson, at Brown-Forman. "I don't know if that's true or not, but it's a significant per cent."
Even at Maker's Mark, where they don't go in for as much barrel character, it's still significant. "Our product, Maker's," said Maker's Mark president Bill Samuels, "was designed for that balance to be fifty-fifty. Deliberately."
Char = Black + Red
Stand a glass of bourbon next to a glass of comparatively aged malt whisky or rum. The bourbon leaps out as a much darker spirit, although all three are clear spirits going into the wood. That's the difference a fresh layer of char makes. What's in there that is making all the difference?
Surprisingly, it's not the blackened top layer. That merely acts as a charcoal filter, pocketing any excess oils that might get through the distilling process. "There's no color derived from the charred wood," said Brown-Forman distiller-in-training Chris Morris. "But there are twelve different sugars in the red layer. This is where the color and the confectionery flavors come from."
Red layers, charcoal, confectionery flavors...Hold on. Let's back up a bit, and make a barrel from the start to understand this better. We'll do some more time travel, but you'll have to walk further than 30 yards this time. It's more like several hundred miles to the upland forests of Missouri and Arkansas. That's where the wild white oaks drop their acorns on the ground to sprout new trees. About eighty years ago, that's where your barrel started.
A lot of the white oak down here is used by Independent Stave Company (ISC) at their Lebanon, KY plant. ISC is owned by the Boswell family, and has another plant in (confusingly) Lebanon, MO. They make barrels for bourbon and wine, all out of American oak; about 500,000 barrels each year go to the bourbon industry.
" We do our own wood," company spokesman Jimmy Wickham said. "The supply of white oak is abundant. We're looking for trees that are about 70 to 80 years old, though the diameter is a better indicator." White oak at that stage has a good amount of tyloses, cellular outgrowths that block the hollow tubes in the heartwood, making the wood particularly waterproof. "White oak is a legal requirement for bourbon," Wickham pointed out, "but the pioneers probably found that white oak just made good barrels." White oak is also relatively low in tannins, the astringent compounds prized
in French oak for wine barrels. Tannins may be good for red wines, but not for bourbon.
Brown-Forman has their own cooperage, Bluegrass Cooperage, and they buy from independent stave makers. "It grows around here," said Morris. "But we don't buy it all from one area. Randomness is our ally. If we depended on the wood from one area, and there was a disaster-fire, drought, over-harvest-it could change the character of the whiskey. We take them at random, wild trees. We let Mother Nature take care of them."
After the wood has been cut, it gets treated differently for Brown-Forman's different whiskeys. "We let the wood air-dry for 9 months for Woodford Reserve," said Morris, "about 3 months for Jack Daniel's. The air, heat, and rain take tannins and oak lactones out of the wood. We want different levels for the different whiskeys."
Shaving and Staving
Things are a little bit different at Independent Stave, but not much. The oak comes to ISC's yard "green," freshly cut, at about 40% water content. It sits in the yard for a month, air-drying. It's not covered against the rain; the oak will not soak up much external water. After a month, the wood, now averaging 30% water, goes into a "pre-dry shed." The pre-dry shed, actually about the size of a large truck garage, is steam-heated to about 97°F and is at around 60% relative humidity at the beginning of a cycle; it's downright tropical in there. Over 30 days, the relative humidity is dropped to 40%, and the wood has somehow dropped to 18-20% water. It's moved to the kiln, where it spends a week at 140°F, subjected to constantly moving hot air. At this point, the wood is down to around 10-14% water content, and it's ready to work.
ISC runs two sides to their actual cooperage, a head side and a stave side. On both sides, the wood is run through planers to get the surface smooth, then cut to length. The heads are assembled on one side, the different sized pieces assembled by eye and pinned together with wooden dowels, and cut to circles. The scraps (and all scrap wood at the cooperage) goes to feed the boilers for the kiln and the pre-driers. The head moves on to inspection, and is ready for the fire.
Staves go through a second planer to get a slight 'cupping' on the inside of the stave. "Barrel raisers" place the staves together to make a standard size barrel, kind of like high-speed puzzle solving as the staves fly into a circle. A temporary hoop goes over the top of the barrel, and the barrel is put in a steambox for 15 minutes to get the wood ready for bending. Then a cone is forced down over the top of the barrel with a noise like the cries of the damned, and a hoop is placed on the top to hold the staves in place. A trip through the "dry-fire" tunnel forces the moisture out while keeping the wood hot and pliable.
The barrel then gets finished off; the stave ends are pressed together to level them, two temporary "bilge hoops" are added around the middle, and the "roll out" machine presses the staves into place with an even outside surface before the "trusser" pushes the hoops on tight. Now the barrel is ready for the fire; the staves are pressed tightly against each other, so fire can't get into the joints, weakening the seal of the barrel.
Into the Fiery Furnace
Heads and barrels are now ready for the flame. "The majority of our customers go for the #4 char level," said Wickham. "We do them to the customer's specifications." There are five levels of char, grades 1-5, but every distiller in the industry uses levels between 3 1/2 and 4 1/2. It takes about 60 seconds per barrel to do a #4 char; the flame is pulled through the barrels with blowers to get an even char. The heads simply move along a conveyer over the flame.
This is a bit different than how they do things at Bluegrass Cooperage. Brown-Forman adds a step to their process: toasting the wood before charring. "It's toasted, not burned," said Morris. "What happens? It sets the curve in the stave, like ironing a shirt. It also starts a degradation of chemicals in the wood. A whole range of celluloses get, well, 'loosened.' The lignin degrades into 3 different vanilla compounds, and the tannins degrade into the orange and red colors, and compounds that will give the whiskey 'mouth feel.' It sets the stage for charring." Brown-Forman toasts the wood
to different degrees for their different whiskeys.
Both men agree: charring creates the red layer, the thin zone under the blackened char where the
sugars in the oak are caramelized, where vanilla-like compounds are created. (By the way, if you're surprised to find sugars in oak...think about what you put on your pancakes.) Photosynthesis is all about sugar creation, and charring merely caramelizes those sugars. Vanilla and caramel, these are the "confectionery flavors" Chris Morris talked about. Charring "also keeps the flavors from toasting in check," Morris said.
Morris's mentor, Brown-Forman master distiller Lincoln Henderson (Malt Advocate Lifetime Achievement Award winner for 2003; see pp. 48), talked about the extensive work he's done on wood management at Brown-Forman. "We're still trying to control it," he said of the somewhat random factor of wood and barrel quality. "We've made some steps at Bluegrass Cooperage in the past two years. The thing we really want to control, and I've pushed this for about 20 years, is the toasting of the barrel. It was just hit and miss. The only thing that would save you is that you'd put enough barrels together to take care of the variation. So we have a process that we've worked on for about five years to really control that. But a lot of things we can't control. You can control where the wood comes from, but that wood's not always going to be the same."
Once the barrel is charred, the heads are inserted and head hoops pressed on by a big yellow octopus-looking machine called a hooper. The bungholes are drilled, the barrels are checked for leaks, given a final sanding, and sent out to be filled. That's when the char finally gets a chance to work.
Pushing and Pulling
All that sugar and vanilla and color is there, in the red layer, waiting to get into the spirit. At most warehouses, that waits on the weather. Some of Brown-Forman's barrels are put to work right away in heated warehouses. Either way, when the warehouse heats up, the spirit expands and pushes into the wood. "The alcohol draws out sugar and vanilla compounds," said Morris. "Water draws out tannic acid." As the whiskey cools, it pulls back out of the red layer, and brings the color, the caramel, and the vanilla with it.
But it's not just a simple transport of flavors, it's not just the char. There's synergy going on with the flavors of the spirit itself. As Wild Turkey master distiller Jimmy Russell put it at the recent Malt Advocate Bourbon Roundtable, " If the flavor's not there going in the barrel...the barrel's still not going to do that much for it." When asked what would happen if vodka were put in the barrel instead of new-make bourbon, Russell admitted that "You'd get a decent product...[but] it wouldn't have much flavor to it." Lincoln Henderson amplified that, saying, "You'd get a nice product...but it wouldn't be bourbon, I mean, it wouldn't taste a whole lot like it."
Lots of things make bourbon the beautiful American spirit that it is. But the color; the caramel, smoke, and vanilla; the dry tannic nip in older bourbons, it's all there courtesy of the char. Whiskey is made with corn from the earth, a generous helping of water to mix things up, air for the yeast and barrels to breathe...fire gives it all the spark, and makes the char. And the char makes the whiskey bourbon.
Other Bourbon/American Classics:
Copper |
Charcoal
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