On The Bourbon Trail

Did you know...  95% of the world's bourbon comes from Kentucky.

In fact, I thought that bourbon *had* to come from Kentucky... not so.  This is just one of the things we learned on the bourbon trail.  (No, there is no actual trail, but we did visit a dozen distilleries in the Lexington-Louisville area).

Here are the actual 5 (Federal!) rules defining bourbon:

• Must be made in the USA (not just Kentucky)
• Must have a grain bill of at least 51% corn
• Must be distilled at no more than 160 proof*, aged at no more than 125 proof, and bottled at no less than 80 proof
• Nothing can be added except water (no artificial colors, flavorings, etc)
• Must be aged at least two years in new, charred white oak barrels

We learned that this is the process:

• Grind the grain and cook it at boiling for a few hours to soften and release the starch
• Cool to below 145°F and add the ground malted barley.  This supplies a pair of enzymes which break up the starch molecules into sugars (starch is a sugar polymer).  At this point, the mash will taste quite sweet.
• Cool to near room temperature and add yeast, and then add a few hundred gallons of the previous fermented batch - this is the reason it is called "sour mash".
• Allow the yeast to grow and consume the sugars...  the byproducts of this are alcohol and CO₂.  In fact, if you get down and peer across the lip of a 40,000 gallon fermenting tank, you can *see* the CO₂ spilling over the edge (CO₂ is heavier than air). 
  
  
  
  
  At the end of the fermentation the mash is 8-10% alcohol, and has a sour taste (see "sour mash", above)
• Pump the fermented mash in a continuous stream to the top of a 50-65' tall copper stripping tower and blow a continuous stream of steam up the tower from the bottom.
  
  
  
  
  This counter-current flow strips the alcohol out of the mash quite effectively.  The vapor coming out of the top of the column is passed thru a condenser.  The condenser output is made visible at a "tail box", where you can see a continuous stream of 125 proof alcohol pouring out of a 2-3" pipe - it is truly impressive.  This product is called "low wine".
  
  
  
• The low wine is then subjected to a second, batch - not continuous, distillation in beautifully formed copper vessels whose shape recalls medieval alembics.
  
  
  
  
  The product from this distillation will be about 160 proof and is called "high wine", "new make" or "white dog".  I've tasted this, and aside from the nose burning alcohol content, the taste is quite strong and depends hugely on the grain bill (proportion of corn, rye, and malted barley in the mash)
• The high wine is then diluted to 125 proof and put into new, charred white oak barrels (pretty much all made at a company named Independent Stave, in Louisville)
• The barrels are stored in a rickhouse, for years.
  
  
  
  
  This is a building which could house 20,000-50,000 barrels.  The smell in there is heavenly!  Because this is where the angels get their share.  You see, the bourbon seeps into the wood of the barrels and evaporates from the outside - this evaporative loss is called the "angels share", and can be quite substantial.
   
  
  
  During this time, the white dog gets transformed into bourbon by leaching the carmelized sugars and other flavors that were formed during the charring of the inside of the barrels.
• Finally, the Master Distiller (a job I would love to have!) goes into the rickhouse(s) and tastes barrel after barrel, coming up with a collection (a batch) which, when blended together, will give the characteristic taste of the brand.  
• There are also small batches of the really good stuff ("small batch", "small batch select"), and even individual barrels ("single barrel", which of course will be more variable from bottle to bottle, since the barrels differ significantly, dependent on their locations in the rickhouses) selected by the Master Distiller.  These two designations are the best of the best, and are priced accordingly.

During the tour we were afforded the opportunity to taste upwards of 40 different bourbons.  No way did this qualify us to be Master Distillers, but it did give us the chance to make comparisons between the low-, mid-, and high-range products.  My take?  The best (read: most expensive) bourbons have the most complex tastes, of vanilla, caramel, butterscotch, smoky wood and spices...  a combination that is impossible to really describe, but which recalls the smell of the inside of rickhouse.

Conclusion:  Buy the expensive stuff, but don't drink it.  Instead, sniff it and sip it very slowly.  My favorite was this one:

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*  BTW, the term "proof" is old.  In colonial times, when one of the major imports to the nascent nation was Caribbean rum, a test was needed to prove that the alcohol content of the barrels being unloaded from ships was as advertised.  There were no laboratories - the test had to be simple and doable right there on the pier.  Well, it turns out that when 50% alcohol is used to moisten gunpowder, the gunpowder will just burn.  Less than 50%, no.  So 50% alcohol came to be called 100 proof.

On The Bourbon Trail