SOUR MASH RYE WHISKEY

Sour mash rye is a whiskey made using a production method that regulates the growth of bacteria that might taint the whiskey. It also helps to ensure the consistency of quality and flavor from one batch of whiskey to the next...  

Most bourbon and rye whiskey distillers use the sour mash method. However, relatively few use the term “sour mash” on their whiskey bottle labels simply because sour mash whiskey is the norm within the industry.

What Is Sour Mash?

In sour mash rye whiskey making, the mash is the mixture of grain and water that is agitated to release the grain starch, which is converted into sugars. “Souring” is the process of adding older spent mash to the new mash, which reduces the pH of the mix, helps to “feed” the live yeast, and inhibits the growth of unwanted bacteria that would spoil the whiskey's taste. It can be compared to the making of sourdough bread using a starter.

Before delving into sour mash, it helps to understand the essential steps involved in the whiskey-making process. The five main steps are milling, mashing, fermenting, distilling, and aging.

• Milling: The grains, which in the case of rye whiskey must consist of at least 51% rye, are ground into a powder.
• Mashing: In the mashing process, water is added to the grain, which is then agitated. This releases starch from the grain, which then breaks down into sugars.
• Fermenting: Yeast is added to the mash, turning the sugars into alcohol, after which, the solution is known as a wash.
• Distilling: The wash is transferred to a still and heated to a high temperature. The resulting evaporation and condensation separates the alcohol from the water and grain residue. The whiskey is often distilled two or three times to further refine the end product.
• Aging: The alcohol, which at this stage is colorless, is put into new charred oak barrels to mature for a minimum of two years. During the aging process, the alcohol content of whiskey will be reduced, and it will take on the familiar golden color from the charred cask.

With the sour mash rye whiskey-making method, spent grain that has been previously fermented and distilled is added into the new mash batch. The old nutrient-rich mash, also known as back set, feed mash, or slop, as it's often used as food for livestock, contains dead yeast, which is a good source of food for the live yeast.

It's important for whiskey distillers to control the pH content of the mash because, if it gets too high, harmful microorganisms can flourish, which would spoil the flavor of the whiskey. The acidic qualities of the sour mash help control the pH levels to avoid the bacteria problem. Fortunately, a distillery has an abundance of spent mash on hand, and it costs nothing.

The majority of American sour mash rye whiskey makers add a ratio of 1-to-3 or 1-to-4 sour mash to new mash. Distillers will often leave the mash sitting for several days before distilling to allow the sour mash to really do its work.

Sour Mash vs. Sweet Mash

The difference between sour mash and sweet mash is that the latter does not use back set or slop in the fermentation process. The distiller will cook the grain, add fresh yeast, and allow the mix to ferment. While distillers of sour mash whiskey use the slop to control bacteria and pH levels, sweet mash distillers need to take much more care to control the risk of bacterial contamination and to ensure the yeast is correctly propagated.

Who Invented the Sour Mash Method?

For many years, James C. Crow was widely credited as the inventor of the sour mash process in around 1838. However, the Kentucky Historical Society discovered a document, dated 1818, that has a handwritten recipe on each side. On one side is the recipe for sweet mash whiskey and on the other a recipe for sour mash whiskey. While there is no reference to an author, the document was attributed to Catherine Carpenter.

Catherine was a widow and mother of 12 children who ran a successful farm in Casey County, Kentucky, that included a distillery. But, just to muddy the waters, among the Carpenter family papers, there is documentary evidence that Catherine could not read or write. Researchers have concluded that, while the sour mash recipe could have been shared among her family and community, it was Catherine who had it written down by someone else for posterity.

James Crow was a Scottish doctor and chemist who, after moving to Kentucky in 1823, began working as a distiller. While Crow may not have created the sour mash method, he took Catherine Carpenter's recipe and perfected and industrialized it to produce larger quantities of whiskey of consistent quality and flavor. For that, whiskey drinkers everywhere should be eternally grateful to James Crow.

Sour Mash Rye Whiskey

Sour mash rye Rye whiskey is not as sweet as bourbon or Tennessee whiskey but offers a slightly more aggressive taste with a spicy and peppery backdrop. Of course, each producer creates their own signature rye, giving discerning consumers a variety of flavors to test on their palate.

Way back in the past, most American rye was produced in Maryland and Pennsylvania. However, the rye industry almost disappeared entirely from the U.S. after Prohibition. Kentucky is now where the majority of rye whiskey is produced. For their product to be called American rye whiskey, distillers must follow strict regulations. The grain mash must contain at least 51% rye. The remainder is often made up of a mix of wheat, corn, or malted barley.

The initial alcohol content must be no more than 160 proof (around 80% ABV). After fermentation, the alcohol is reduced to no higher than 125 proof (62.5% ABV). The whiskey then has to be aged for no less than two years in new charred oak casks.

Rabbit Hole Boxergrail Kentucky Straight Rye Whiskey is a sour mash rye that offers a depth of flavor with a balance of sweet and spice. You'll find hints of citrus, butterscotch, and black tea for a unique taste on your palate.