27 CFR 18.15: Right of entry and examination.

Appropriate TTB officers may at all times, as well by night as by day, enter any concentrate plant to make examination of the materials, equipment, and facilities thereon; and make such gauges and inventories as they deem necessary. Whenever appropriate TTB officers, having demanded admittance and declared their name and office, are not admitted into such premises by the proprietor or other person having charge thereof, they may at all times use such force as is necessary for them to gain entry to such premises.