To create The Balvenie PortWood 21 year old single malt whisky, a marriage of rare Balvenie is transferred to port casks, or pipes, which have held fine port wines. Here it is sampled regularly by The Balvenie Malt Master David C. Stewart MBE to ensure that just the right amount of character is imparted by the port casks, enhancing and developing the single malt whilst preserving its original characteristics.