27 CFR § 19.229 - Deferred payment and prepayment of taxes.
There are two basic methods of paying the tax on distilled spirits withdrawn from bonded premises: Deferred payment and prepayment.
(a) Deferred payment. Under the deferred payment system, the proprietor may withdraw spirits from bond after tax determination but before payment of tax. The excise tax paid is based on the amount of spirits removed from bond during each return period. In order to pay taxes under the deferral system, the proprietor must file a withdrawal bond or unit bond unless the proprietor is exempt from furnishing such bond under § 19.151(d). For detailed information regarding return periods and filing requirements under the deferred system, see §§ 19.234, 19.235 and 19.236.
(b) Prepayment. Under the prepayment system, the proprietor must pay the distilled spirits tax after tax determination but before withdrawal of the spirits from bonded premises. See § 19.230 for conditions that require prepayment of taxes.