27 C.F.R. § 25.293
Record of ballings and alcohol content
The brewer shall maintain a record of the ballings of the wort produced, and of the ballings and the alcohol content of beer and cereal beverage transferred for bottling and racking, between breweries in bulk conveyances, and to pilot brewing plants. Records showing ballings and alcohol content need not be consolidated and averaged daily unless the brewer so desires.