In my lifetime I have tasted from many bottles of Bourbon that were 50 or more years old – not the Bourbon but the bottling. These whiskeys taste different from today’s products of the same name. The question is why? What makes these old bottles taste different? Let us look at the six sources of flavor and see what we can find out.

Grain: The grain used before the 1940s was not hybrid grain. This could be a source of the flavor change as corn and rye have gotten sweeter and produce a higher yields. The older distillery practices may also have used more white corn versus yellow or a combination of the two types. The distillers also did not have the ability to use enzymes in the mash so they had to use more malt to get their conversion of starch to sugar.

Water: More distilleries today depend upon reverse osmosis to clean their water from the city water system than having their own source of well or spring water. This water was used not only for making the mash but also when cutting the whiskey to proof when bottling the Bourbon. The lack of mineral content in the water because of this technology may be changing the source of the flavor in the whiskey.

Fermentation: Distilleries of today have a better understanding of the science of microbiology and do a better job of preserving their yeast strain than was possible a hundred years ago. Yeast mutations of that period probably took longer to be noticed. Wooden fermenting vats were also harder to keep clean and there may have been more bacteria influences on the whiskey. These will change the flavor profile as well.

Distillation: There is much more use of stainless steel in the modern distillery. The stills of a century ago were copper – a lot of copper. Copper distillation was a selling point for the whiskey so the distilleries used copper in every way possible. Many distilleries also distilled at a lower proof – usually between 120 and 130, allowing for more grain flavor in the whiskey.

Maturation: Barrel entry proof was between 90 and 105 proof for much of the period up to the 1960s. This lower barrel proof had a big impact on the flavor of the whiskey. It also meant that less water was added to the final product at bottling. Many people mention old growth wood for barrels as a factor, but I think not because older oak trees do not make good barrel staves so most staves are cut from trees between 70 and 90 years of age now and most likely then as well. A bigger factor to me would be the environment as air and water quality changed affecting the flavors held in the oak. Barrel size has also changed from a 48 gallon barrel to a 53 gallon barrel. Less surface contact of wood to whiskey today. Barrels also got rotated and moved more in the old days as the government guager came in and spot checked barrels for fill level.

Bottling: There are many more efficient ways to filter whiskey today than there were a century ago. This means more flavor is being removed from the final product. The water used to cut to proof was usually the distilled version of their water source and probably was not a completely neutral flavor.

All of these changes to the sources of flavor have had an impact on the flavor in the bottle. The big unknown is how much impact that time in the bottle has had on the flavor. While many people have said that whiskey quits aging once it is in the bottle, it does not mean that it quits changing. I believe that over time there will be some small changes in the bottle as seals begin to fail and air gets into the equation. This is a slow change, but a change none the less.

Old bottles of whiskey do taste different from modern whiskey,  I have listed many reasons for this change here but I am sure that have missed others. Enjoy those old bottles when you find them, but remember that the whiskey on the shelf today will be someone’s dusty bottle fifty years from now and they may asking the same question as today: “why does this Bourbon taste different from what is my bottle today?”


Photos Courtesy of Maggie Kimberl