27 CFR §24.107

Bonded wine premises which will be used for the production of wine or for production processes involving the use of wine will be designated a bonded winery unless the proprietor applies for a bonded wine cellar designation. If the proprietor of a bonded wine premises designated as a bonded winery does not engage in wine production operations, the appropriate TTB officer may notify the proprietor that the designation of the premises is changed from a bonded winery to a bonded wine cellar.