TTB states that taxes on beer are determined when the products are removed from the brewery premises for consumption or sale — so the obligation attaches to a physical movement rather than to a transaction with a customer.
Two consequences follow, and both are structural. First, excise is a liability of the brewery rather than money collected from anybody — unlike sales tax, which a business holds on a customer's behalf and passes on. Booking excise as though it were a sales tax puts it in the wrong account, driven by the wrong record, and reconciles against the wrong thing. Second, because the amount is a function of quantity removed rather than of revenue, the entry cannot be derived from a percentage of sales. It has to be built from the removal records. TTB also describes the tax for a return period as resting on net taxable removals — removals for consumption or sale, less beer returned to the brewery within that same period — so a file that captures shipments but never captures returns will accrue more than is owed. Rates, reduced rates, thresholds and filing frequency are TTB's to set and yours to confirm with them and your CPA; we do not state them, and we build the structure that carries whatever they turn out to be. Where the sales-tax side of the taproom has separately drifted, that is a sales tax cleanup and a genuinely different problem.