Mahogany is a light brown color if left not finished. Well, you can use a wine thermometer that attaches towards bottle.
Will your cellar be in the interior of the home and is it adjacent to some other wall? This famous Loire wine manufactured with Sauvignon Blanc grapes puns a famous wine spot. https://cyan-lark-kbzsw4.mystrikingly.com/blog/r-u-hennessy-brand-name-r-u-cognac-hang-d-u-th-gi-i