About 95% of the barley for Japanese whisky is imported from Scotland, where it’s malted by Scottish maltsters. Yamazaki uses a mix of malted barleys, mostly non- and lightly-peated, unlike Scotch distillers who trade whisky for different styles. Instead, Yamazaki employs various methods for blending.
The wort is fermented in modern stainless-steel and traditional Douglas Fir washbacks. Yamazaki uses two types of yeast: distiller’s yeast for a clean, estery wash and ale yeast for fruity, creamy notes. A long, up to three-day fermentation contributes to fruity and grassy notes, unlike shorter fermentations which produce oily, nutty flavours.
Yamazaki’s still house features six pairs of copper pot stills of different shapes. Straight-sided stills give a fuller, creamier spirit, while rounded ones produce a lighter spirit. The first distillation is direct-fired, adding a toasted character, while the second uses indirect steam heating, yielding a lighter spirit. Some stills are imported from Scotland, others made locally. Both worms and condensers are used, with the twice-distilled spirit at 65-70% abv being diluted to 60-63% before aging.
Yamazaki uses five types of oak casks in various shapes and sizes, including bourbon barrels, hogsheads, and Suntory’s original puncheons. Casks are made from North American white oak, Spanish oak, and Japanese Mizunara oak. White oak imparts vanilla and coconut flavors, Spanish oak adds fruity and chocolate notes, and Mizunara provides a distinct eastern character with sweet incense and citrus notes. The casks vary in size and degree of char, and maturation time. Yamazaki warehouses hold only 15% of the whisky; the rest is aged at the Omi Aging Cellar. Earthquake-resistant concrete warehouses stack barrels four high.
Like their Scottish counterparts, Japanese Whisky is aged in pot stills but benefits from Japan’s warmer climate, which enhances oak flavour extraction. This, combined with Japanese oak, gives Yamazaki whisky its truly unique character. The blenders at Yamazaki, who taste 200-300 samples daily, ensure each vatting is harmonised for six months before bottling, with no caramel used for colouring—only the oak’s influence determines the whisky’s hue.