Scatterings of information exist prior to his coronation and it is a matter of piecing the puzzle together and coming up with a "best guess" as to how much time he actually spent in Bristol before his ascension to the throne. In fact, my current work in progress surmises what might have happened during a period when he may have resided in Bristol Castle, where he concocts an ambitious plot to usurp the Crown from his brother.
However, after his coronation the records of John's visits to Bristol are remarkably accurate. For example, on 5th February 1205, he wrote to the merchant ,John De La Warr commanding that his Justiciar, the Earl of Essex, be presented with "20 casks of his good wine at Bristol." On the 12th of the same month a payment of 41s, 6d (41 shillings and 6 pence) be made to transport "30 tuns of wine from Bristol to Tewkesbury."
The port of Bristol had, since the time of the marriage of Henry II to Eleanor of Aquitaine, been the centre of wine importing from France. Vintners & Merchants brought thousands of barrels into the port each year and the reputation and quality of the product was beyond question. To give you some idea of the money spent by John on wine, in April 1205 he ordered that a payment of £568 be paid to several merchants in the town for wine he had ordered. John was so enthusiastic about the wine procured by Bristol merchants that he regularly had barrels sent to castles around the country, where he would be staying or entertaining.
For the next several hundred years, Bristol would dominate the wine trade and trading links with France, Spain and Portugal still exist today.