The Yamazaki Whisky Making Process

"Diversity in the whisky-making, resulting in diversity of flavor"

Yamazaki’s pristine water used in the early stages of whisky-making

Katsura, Uji, and Kizu Rivers, merge at Yamazaki.
The whisky water is derived from this naturally clear and mineral rich water source right on the distillery premises.

In whisky-making, water is one of the key factors that determine the quality of whisky. In the area surrounding the Yamazaki distillery, selected after a thorough search for quality water all over Japan, spring water named “Rykyu no Mizu” (water of the imperial villa), selected as one of the hundred best natural mineral waters in Japan, and continues to bubble forth today. For the process water used at the Yamazaki distillery, this pure and high-quality groundwater that has been nurtured slowly over several eons of time is used.

Malt whisky is made from water and barley. We start by germinating and drying carefully selected two-rowed barely to produce malt. The malt is then finely ground and mixed with water in a mash tun, where enzymes in the malt break down the starch content into sugar. We then slowly filter the mixture to obtain clear, unclouded wort.

A display shows harvested barley and ground barley used during the mashing process.

Wooden and stainless steel wash backs

Next, we transfer the filtered wort to our wash backs and add yeast. The yeast converts the sugars in the wort into alcohol and carbon dioxide while generating the distinctive flavor components that define whisky. The fermented liquid that results from this process, called wash, can have many different characteristics depending on the factors such as the type of yeast used and the conditions under which it was fermented. 

A stainless steel washback where they apply yeast into the mashing process.

At the Yamazaki distillery, both wooden and stainless steel wash backs are used to produce various types of whiskies while carefully selecting appropriate yeast from among the several types of yeast that would best suit the desired whisky flavors.

Wooden washbacks used to produce rich-flavoured malt using naturally occurring lactic acid bacteria and other microorganism populations.

A variety of pot stills

The first pot still in the distillation floor.

The wash produced during the fermentation is now transferred to pot stills to undergo the distillation process twice, which results in a liquid with high alcohol concentration called “new make” ) a clear, colourless malt whisky fresh from the stills). By this time, the framework of the whisky’s ultimate flavor profile is already in place.

Multiple pot stills on the right side of the distillation floor.

At Suntory, we select from among a variety of pot stills in different shapes and sizes depending on the distinctive flavours we want to bring out in the whiskies. Suntory is one of just a tiny handful of distilleries around the world that work with several different types of pot stills.

Persistence to cask maturation

A variety of casks filled with different types of flavors stacked inside the maturation warehouse.

The distilled “new make” is then placed in casks where they will slowly age and mature. Maturation is a complex process of flavor development that depends on a variety of conditions. Even details like the size, shape, material, storage location of casks, and the climate of the region can make the same “new make” mature differently. The possible combinations are truly endless and it is truly the “mystery of cask maturation.” In this way, Suntory’s diversity in the whisky-making process from malting, mashing, fermentation and distillation through cask maturation allows it to produce hundreds of thousands of casks of whiskies each with distinctive flavors.

Rows of casks sleeping and neatly organized by date and kind.

The skill of master blenders brings out a variety of flavors 

Yamazaki Malt Matured in Sherry Butt distilled in 1989 displayed in the Whisky Library.

Finally, a variety of whiskies matured in casks are handed over to the care of blenders and they evaluate the extent of maturation of each cask and carefully select whiskies that will best be vetted into a final product with exactly the right characteristics. Our blenders taste up to two or three hundred types of whisky a day and predict when each cask will be at its best and when it should be used. These skilful craftsmen also manage our collection of whiskies by foreseeing what kind of whiskies will be needed in the future. Whisky-making that requires a long period of time, starting from malting through final batting, to determine the flavors of products can be considered as “collaborative work between blenders of the past, present and future.”

Unique Yamazaki Malt matured in Hogshead distilled in 1989 displayed in the Whisky Library.