Kentucky whiskey from Kentucky grain

Kentucky is famous for its Bourbon whiskey. Ninety-five per cent of the world’s supply of Bourbon is produced in Kentucky with over 100 distilleries across the state.

Central to Green River Whiskey in Owensboro, Kentucky’s ethos is local grain. The Irish Farmers Journal visited the distillery last May.

Corn, or maize as we know it in Ireland, is the main ingredient in Bourbon and all of the corn supplied to the distillery is grown in Kentucky. The distillery is currently diversifying its range and uses wheat and rye for two of its main products, while barley is also an ingredient.

Farmers in the area struggle to grow these crops, so these ingredients are imported from the Pacific North West of the country, so states like Washington and some from Canada.

However, the distillery is open to a local supply of these grains, if farmers can manage to grow the crops nearby or even in another part of the state.

It was clear from visiting the distillery that local product is important. Trucks delivering grain into the hopper with family names on those trucks passed by through the tour.

You also get the sense that this distillery is very proud of what it does and is willing to display the whole process – what you see is what you get. You are brought through the process from grain delivery to barrel, bottling happens off site.

When the bottle comes back, it is impressive with a detailed horseshoe on the bottom representing the state’s strong horse racing tradition.

The process

Grain is tested for moisture on arrival and enters the bin through the hopper. This bin can accommodate six semi lorries that carry around 40t each. There are three 12,000-gallon mash tubs and these are filled with grain and water from four limestone wells.

Grain enters fermentation tubs where yeast is added for five days. This turns the mix from sweet to sour. There are 27 fermentation tanks altogether in the distillery.

The slop from the tanks is given to local farmers for free. They can come to the distillery and pick it up or it can be delivered to farms.

This mix in the distillery is then moved to the four-storey column still. The steam rises to the top and takes off the alcohol.

Once the alcohol is produced, it moves across the distillery yard in a pipe to be put into a barrel.

Barrels for Bourbon have to be new and charred and the whiskey cannot go in with an alcohol level above 125, so purified water is added if needed. Barrels have to be stored for at least one year and a day. However, Green River is aiming for five years in barrels before release.

Irish whiskey has to be kept for three years and a day.

One of the oldest distillery licences in Kentucky

The distillery was founded in 1805 and went through changes over the years including prohibition when the sale of alcohol was not allowed in the US.

It was taken over by Bardstown Bourbon Company in 2022 and continues to produce Bourbon whiskey. Wheat whiskey was launched in 2023 and rye whiskey in 2024.

However, through all the changes it has kept its distillery’s licence number the same since 1885 – DSP KY 10. This is now the oldest distillery licence number in Kentucky.

Lot number today

The ‘10’ means it was the 10th distillery licensed in the state. If the distillery were to get a lot number today it would be in the 20,000s.

Requirements for Bourbon

Bourbon has to be made up of at least 51% corn. At Green River it is 70% corn, 21% rye and 9% barley. There is no requirement for that grain to be from Kentucky, but Green River uses only Kentucky corn.

Irish whiskey has no requirement to be made from Irish grain, while some distilleries pride themselves on using Irish grain others use very little, if any. There are requirements to use different types of grain. Many distilleries In Ireland import maize and other grains to produce whiskey.

The Irish whiskey technical file, which outlines how Irish whiskey is to be produced, is currently under review by the Department of Agriculture.