Bourbon - Storage
Each distillery has their own preferences for storing the barrels.
In the past warehouses with a height of 4 to 5 floors were built. On each floor between 3 and 6 layers of barrels are stored.
The warehouses have a skeleton of bars and girders that make it possible to roll the barrels horizontally. Between this skeleton there are elevators that make the vertical movement of the barrels possible. An ordinary warehouse has a capacity of approximately 20,000 barrels.
In these warehouses a very special climate is created. Below the roof there are very high temperatures in the summer, while at the bottom it stays as cool as if the room was air-conditioned. For temperature equalisation with the outside air a warehouse has many windows.
The whiskey matures differently on each floor. In the past the barrels were therefore rotated. Rotating means the barrels are moved to different pre-determined positions within the warehouse during maturation, so each barrel can profit from the good positions in the middle of the warehouse. However, a certain part of the warehouse (usually 1/3 of the total capacity) must stay empty for rotation. Maker's Mark was one of the few distilleries that still rotated their barrels in 1999.
The other distilleries have chosen a different way. They no longer rotate but mix barrels from different positions in the warehouse before bottling. With this method you avoid the labour-intensive rotation of the barrels, you use up the whole capacity of the warehouse and you gain an area in the centre of the warehouse where you find extraordinary barrels for small batch bourbons and single barrel bottlings.
In 1996 several warehouses of the Heaven Hill distillery burned down. The burning whiskey pushed its way through the distillery down to the river. Thus also the distillery burned down, and the whiskey burned on the river for the rest of the night.
In order to minimise the risk of fire, today each warehouse has a sprinkler system, and the warehouses are built at a safety distance. As passive safety, the wooden skeleton is built in such a way that a warehouse collapses during a fire and doesn't damage other warehouses.