Bourbon Steps Out of Its Overalls
Wednesday, April 29, 2009
LOUISVILLE -- "You're going to hear all sorts of stories this week about yeast strains," Chris Morris, Woodford Reserve's master distiller, told me when I arrived here. He was not kidding.
"We saved our yeast strain from the big fire in 1996," said Josh Hafer at Heaven Hill Distilleries.
"We've been using our yeast strain since Prohibition," said Angela Traver at Buffalo Trace Distillery in Frankfort.
"Our five yeast strains are patented," said John Rhea at Four Roses in Lawrenceburg. "Two of our yeast strains have an apple flavor note."
A lot of people come to Kentucky this time of year to wear fancy hats, drink mint juleps and bet on horses. That's all fine and dandy. But I spent my seven days here visiting eight major bourbon distilleries: touring mill rooms, fermenting rooms and bottling rooms and tasting a lot of whiskey. Along the way I had eight separate discussions about the finer points of mash, rick houses and, yes, yeast strains, all in an effort to better understand why I love bourbon.
That's not to say anyone needs to understand esoterica to enjoy bourbon, easily the most accessible and affordable premium spirit in the liquor store. It always surprises me that mixologists or other spirits "educators" so often steer newcomers directly toward Scotch or Irish whiskey or, these days, to trendy ryes. Often the newbies' only experience has been with white spirits, such as flavored vodkas, or with bad cocktails. I've seen it happen many times: The newbie takes one sip of smoky Scotch or spicy rye and doesn't take a second.
Bourbon, on the other hand, is too often dismissed by misguided whiskey snobs as "sweet," which has become the euphemism in food and drink circles for "less sophisticated." This is a shame.
Certainly anything made with corn and aged in an oak barrel for a decade or more can be sweet. But no two Kentucky bourbons are the same, even with strict guidelines set down by Congress in 1964. By law, you can produce bourbon anywhere in the United States, as long as it is made with at least 51 percent corn; that is bourbon's key difference from single-malt Scotch or Irish whisky, which are made with malted barley. Bourbon also must be aged for at least two years in new, charred oak barrels and may not be distilled higher than 160 proof (much higher than Scotch) or put in the barrel at higher than 125. Finally, bourbon must be all natural, with no additives or coloring.
Remarkably, those guidelines leave a lot of room for individual style. That diversity is what makes the bourbon category exciting, and it's undoubtedly why sales of super-premium bourbon and Tennessee whiskey have doubled in the past five years, as reported by the Distilled Spirits Council of the United States. As Maker's Mark's master distiller, Kevin Smith, said: "We're not about bib overalls anymore. This is a city boy's drink."
Some of the variation has to do with terroir. Kentucky has limestone-filtered water that is free of iron, which spoils whiskey, but it's a little different at each distillery. "You could take everything we do here and move it to another part of the state, and it would taste a little different," said Jimmy Russell, master distiller at Wild Turkey in Lawrenceburg.
Beyond terroir, the differences boil down to several major factors, and only one of them is the proprietary yeast strain of each distillery. "Most all of the distilleries kept their yeast strains going during Prohibition. I used to tease the old-timers that they must've been making bourbon out in the hills," Russell said.
Truth be told, all the yeast talk does begin to feel a little superstitious. But I'm no microbiologist, and each distillery's unique strains do make for different-tasting bourbons, so I can see why they're spoken of in such magical terms. Anyway, the yeast is added to a mash during fermentation, where it turns sugars into alcohol. The mash mix is the second big factor. Almost all bourbons are made with about 70 percent corn, but what really matters is the type and percentage of the secondary and tertiary grains used (usually rye or wheat, and malted barley). Wheated bourbons such as Maker's Mark, Pappy Van Winkle's or W.L. Weller age differently and have a completely different flavor profile from that of most bourbons, which use rye as the predominant second grain. Some, such as Four Roses or Wild Turkey, use a higher percentage of rye.