27 CFR §25.145

1. (a)Each brewer who transfers beer to another brewery of the same ownership (as defined in § 25.181), or who exports beer without payment of tax, as provided in § 25.203, shall plainly and durably mark each tank, tank car, tank truck, tank ship, barge, or deep tank of a vessel in accordance with paragraph (b) of this section. These marks may be placed on a label securely affixed to the route board of the container.
2. (b)The brewer shall mark each container with—
   1. (1)The designation “Beer”;
   2. (2)The brewer's name;
   3. (3)The address of the brewery from which removed;
   4. (4)The address of the brewery to which transferred or the marks required for exportation in part 28 of this chapter, as applicable;
   5. (5)The date of shipment; and
   6. (6)The quantity, expressed in barrels.