Whiskey barrels are the industry standard for storing and aging whiskey. The process of making a single 52-gallon barrel can take months, but it is worth the wait.
If you enjoy Tennessee or Bourbon whiskey, then it is the barrels that play a big part in your enjoyment of the spirit. They are responsible for adding a characteristic color and flavor to the liquor.
Here are the steps that go into making an American bourbon or Tennessee whiskey barrel.
How is a whiskey barrel made?
1. Choosing the right lumber
To make barrels, the first step is selecting the best wood for the job. American White Oak is sourced from the United States and Eastern Canada. Once felled, it must be left to mature in the open air for several months to help release the tannin. Bourbon is not a sweet drink so removing the tannins from the lumber is essential as they are responsible for adding a bitter flavor to whiskey.
2. Cutting the staves and heads
The main parts of a barrel are the staves that make the sides, and the heads which are used for the end of the barrel.
Before sawing the wood, it is firstly planed to help make the wood more resistant and to lighten its color. The staves and heads are then cut into appropriate lengths before having holes drilled into each side of them. These holes are used to insert dowels which allow the pieces to be attached.
3. Raising and steaming the barrels
A temporary steel ring is used to hold 31-33 staves in place. The staves must be evenly spaced, or else leaks are more likely at the end of the process.
After assembling the pieces, the wood is steamed to make it more pliable. As the wood becomes flexible, additional rings are attached. By this stage, the barrel will look like it is completed. But before the barrel is ready for use, there is more work to be done.
4. Toasting the inside
The inside of each barrel is toasted to a certain temperature and for a precise time. The exact process is a tightly guarded secret as it plays a major role in adding flavor to the final whiskey.
American White Oak contains a unique mix of sugar and tyloses which, once heated, turns to caramel. It is this caramel that is responsible for the whiskey’s brownish color.
5. Charring the barrel
Like the toasting stage, during charring, the heat is focused on the inside of the barrel. The major difference with this stage is that the wood is exposed to a much hotter flame.
Only the surface of the wood has a chance to char as it is a brief burst of heat. The resulting charcoal surface will eventually act as a filter once filled with whiskey. It draws out the more intense flavors from the raw whiskey (known as subtractive maturation). Without this step, the final liquor wouldn’t be as smooth.
6. Hoop forming
The barrel’s hoops are made from steel coils and are cut into three different lengths: the head loop (71″), quarter hoop (75″), and bilge hoop (79″). These hoops are riveted together and then attached to the barrel with a special hooper machine.
The barrels must be given time to completely cool before the temporary hoops are removed and the final hoops get attached. Adding them too early could result in the wood shrinking and the hoops falling off.
7. Adding the bunghole
The final step in making a whiskey barrel is drilling a bunghole. This is used to add and remove whiskey from the barrel. Once the hole is made, a gallon of water is poured into the hole and air pressure is applied. If there are any leaks the barrel maker will know because bubbles will appear.
If the barrel passes the final quality checks, a plastic bung is plugged into the hole and the barrel is sent to a distillery where it can be used to mature whiskey.
Not all barrels will pass their quality test. Any leaky or faulty barrels are sent to the cooper station to get fixed. This usually involves replacing a head or stave and requires an experienced craftsman to repair it.
Commonly asked questions
What are whiskey barrels made of?
Whiskey barrels are mostly made of American White Oak, which is a slow-growing tree that takes about 20 years to reach maturity. This type of wood is chosen for its dense structure, which is leak-resistant and imparts a unique flavor to the whiskey.
What is a bung?
A bung is a hole in the barrel which allows the master distiller to add and remove whiskey, bourbon, and scotch.
What are charred barrels?
Charred barrels start as new, American White Oak whiskey barrels and are scorched to create a unique flavor profile and color when aging whiskey.
What are barrels used for after they’ve aged Tennessee or Bourbon Whiskey?
The charred oak wood can be reused in many industries because of its strong and sturdy nature. Some use it as an effective way to heat homes during winter months while others turn them into tables, garbage bins, and even chairs.
Which liquor is aged in oak barrels?
The most common liquors that require aging in barrels are Scotch, Bourbon, Tequila, and Rum.
Now you know how to make a whiskey barrel. As you can see, it is a labor-intensive process that requires specialist machinery and tools. If one of these steps is missed, the whiskey makers won’t be able to make whiskey that has a consistent flavor and color.
If you like the idea of owning your own barrel you may be pleased to know that they can be purchased fairly easily from online sellers. In the United States, they start at around $150 but can fetch a much higher price depending on the quality.