Fermenters

The distilling industry and its tools have evolved over the centuries of whiskey making. Most people think of this evolution in regards to the still, when it gained a worm for cooling vapor and then into a column still. However, the same evolutionary energy was changing the fermenter as well as the still.

In the early days of Kentucky whiskey making, the fermenter was most likely an empty barrel of 48 gallons in size. If the distiller was able to afford it, then they would make a wooden fermenter, usually out of oak since oak is tight grained and holds liquid and is readily available, of a size that would fill the distiller’s pot still – anywhere from 50 to 100 gallons in most cases. As the economy of Kentucky improved and products were being brought into the State, Cypress wood became the wood of choice for making fermenting vats.

The vats also grew in size as the technology of the still improved. It takes a lot of distiller’s beer to keep a column still busy making whiskey. That meant that fermenters had to be large with capacity measured in the thousands of gallons. And even then, it took multiple fermenters working at the same time to feed the still every day. Distilleries such as the O.F.C. Distillery in Frankfort, Kentucky in the early 1870s had dozens of small 50 gallon oak fermenters feeding their pot stills.

Cypress was chosen as the preferred wood for two main reasons. The first reason was that the wood was very resistant to rot and would last a very long time before it needed to be replaced. The second reason is that the wood itself did not add flavor to the beer. Cypress trees are also very large trees producing wood staves large enough for the huge vats required to ferment the beer needed to feed the stills. The wood itself does not add flavor to the beer, but if they are not cleaned thoroughly, bacteria can grow in the wood joints of the vat’s staves. That bacteria can change the flavor of the beer in very unpredictable ways and most of those changes are not for the better. Cleaning these wooden vats was a labor intensive and expensive procedure. It took many years to improve the technology of the Cypress fermenter, but when that improvement came, distilleries were quick to adapt to the new technology. Some distilleries built concrete tanks into the floor of the distillery to do their fermentation. These tanks were lined with other materials and hard to keep clean. At the O.F.C. Distillery, they lined these tanks with copper. Later, after the repeal of Prohibition, the Bernheim Distillery in Louisville, Kentucky built concrete tanks lined with tiles and grout. These fermenters were not an economical replacement to Cypress because they were still expensive to build, hard to clean and not as durable as Cypress.

The technology that improved fermenters was the economical production of stainless steel after World War II. Stainless steel does not impart flavor to the beer and does not rust or break down in the mild acid produced in the fermentation process. It does not have as many joints as a Cypress vat and is a lot easier clean between batches of beer. This means less labor expense and more economical production of whiskey.

The stainless steel vats also allowed for the development of closed fermenters, allowing the distillers to capture carbon dioxide. This became important to distilleries located in urban areas that had regulations dealing with air quality.

As tourism became an important part of the distilling industry in the late 20^th century, many distilleries have decided to pay homage to their heritage by using Cypress fermenters. Some distilleries that were around before the Second World War still have Cypress fermenters in use. Others have had to build new Cypress fermenters and that became an expensive process.

Cypress is now a protected species and new trees are not being cut. Distilleries had two options for obtaining Cypress wood for their fermenters. The first method was to find a distillery that was closed but still had Cypress fermenters that could be purchased. This meant the size of the fermenter was pretty much determined by the existing fermenter – the distillery purchasing the used fermenter could always trim the size of the stave to make a smaller fermenter, but they could not make a larger one from the same wood. The other option is to find Cypress trees that were cut many years ago, but were allowed to sink into the bottom of a river or swamp for some reason or another. The Cypress wood is resistant to rot and such logs are being recovered from rivers and swamps where they sank in the water over a century ago. This is expensive wood to recover, but it is available.

The fermenter has evolved over the past two and a half centuries. Some distilleries are paying homage to the older technology of Cyprus fermenters for their tourism experience, but the vast majority of the whiskey made today is being made using the latest stainless steel technology for their fermenter vats.