Definition - What does Bonded Wine mean?
Bonded wines are wines which have been purchased and held in a bonded warehouse that is approved by HM Customs & Excise. They will remain in bond until they go through customs and/or the taxes and other fees on the wines have been paid.
This is also a process that wineries go through once a wine is bottled.
WineFrog explains Bonded Wine
Wineries are in the business of turning grape juice into alcohol. As alcohol is taxed, wines must be put in a designated warehouse until the taxes are paid.
However, the wines which are placed in the warehouse are to be sold at a later date. This means that the winery can avoid paying taxes on the alcohol once it is sold, as the taxes are paid by the purchaser.
This is also practiced with merchants and wine brokers so they can pass the taxes down to their buyers.