Water and Alcohol Molecules and Barrels

  • Since a water molecule is very small, it is easier for it to escape through the barrel than the much larger alcohol molecule.  Because the atmosphere at the top of a Rickhouse is very hot and dry, the water molecules escape much faster than the alcohol molecules thus driving the proof UP in those barrels also concentrating the flavors.
  • Barrels at the top of a Rickhouse age at an accelerated pace.



  • Conversely the atmosphere at the bottom of the Rickhouse is moist and cool.  Since a water molecule is very small, water can penetrate the barrel from the surrounding moisture and that drives the proof DOWN in those barrels.
  • Barrels at the bottom of a Rickhouse age at a slower pace, and the flavors are not as pronounced.

  • With 3 barrels on each floor, you can easily see by this diagram that bourbons age differently all through the house.  So it really showcases how a Single Barrel Bourbon will taste a little different from barrel to barrel.


  • If you mingle several barrels together from different floors as in a Small Batch Bourbon, then that product will taste more consistent from bottle to bottle, and batch to batch.


  • Mainline bourbons like Evan Williams Black Label, and Jim Beam White Label are from a larger number of barrels collected from all areas of the Rickhouse.


  • Small Batch and Single Barrel Bourbons generally come from more specific areas of the Rickhouses, and in either one Single Barrel, or a dump of a lesser number of barrels for a Small Batch.


  • Different distilleries define Small Batch differently, so keep that in mind with # of barrels in a dump or areas of Rickhouses, or specific Rickhouses themselves as the Small Batch.
About bernie
-Whiskey Professor for Heaven Hill -2009 and 2012 Icons of Whiskey Award Winner - Whiskey Ambassador of the Year US and Global

2 Comments on Water and Alcohol Molecules and Barrels

  1. This is the best explanation of the water/alcohol evaporation process I’ve seen. Simple and informative. Well done!

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