The black-toned part of the cellar connecting each section is made of Alder wood. In this project, the Alder wood looks modern and metallic due to its dark finish. Read more: https://www.customwinecellar.com/custom-metal-wine-racks/metal-wine-racks-for-an-under-the-stairs-wine-cellar/ Custom Wine Cellar 35 Hallcrest Dr, Ladera Ranch, CA 92694 Phone: (949) 771-2712