27 C.F.R. § 25.24
(a) Taxpaid beer. Beer of a brewer's own production on which the tax has been paid or determined may not be stored in the brewery, except as provided in § 25.25 or § 25.213. Beer produced by other brewers may be stored at the brewery under the following conditions:
(b) Untaxpaid beer. Packaged beer on which tax has not been paid or determined may be stored in any suitable location in the brewery.
(Sec. 201, Pub. L. 85-859, 72 Stat. 1389, as amended (26 U.S.C. 5411))
[T.D. ATF-224, 51 FR 7673, Mar. 5, 1986, as amended by T.D. ATF-268, 53 FR 8628, Mar. 16, 1988; T.D. TTB-25, 70 FR 19883, Apr. 15, 2005; T.D. TTB-79, 74 FR 37404, July 28, 2009]