A barrel rack system that may be modular and customizable to fit an existing storage space. The barrel rack system may include first and second rack units, each defining a hexagonal storage cell that is configured to hold and store a barrel. The first and second rack units may be detachably coupled together so that the hexagonal storage cells thereof are adjacent and parallel to one another. The first and second rack units, when coupled together, may collectively define an elevated storage cell that is capable of holding/storing yet another barrel. The elevated storage cell may be offset relative to the hexagonal storage cells. Additional rack units may be coupled to the first and second rack units horizontally and/or vertically to effectively conform the barrel rack system to the existing storage space.