What type of structures are racks associated with in US maturation warehouses?

Racks in US maturation warehouses are associated with multi-story buildings primarily because these structures are designed to optimize space utilization. In the spirits industry, especially for aging products like whiskey or other distilled spirits, maximizing vertical space is crucial. Multi-story buildings allow for the increased storage of barrels in a compact footprint. This stacking capability enables distilleries to efficiently manage their inventory while ensuring that the barrels receive proper airflow and temperature regulation, which are essential for the maturation process.

In contrast, single story buildings may limit the amount of aging product that can be stored, and warm warehouses might not provide the controlled climate necessary for optimal maturation. Similarly, underground facilities might not be practical for aging spirits in the same way as above-ground structures, which allows for better monitoring of environmental conditions. Therefore, the design and functionality of multi-story buildings make them the preferred choice for maturation warehouses in the spirits industry.