How does the high altitude of Mars Shinshu Distillery affect aging?

Ah, when it comes to Mars Shinshu, I'm wide awake! The altitude of this place is indeed a secret weapon for the flavor of their whisky.

Simply put, you can imagine an oak barrel as a "living thing" that breathes. The maturation of whisky is largely a process of continuous interaction and exchange of substances between the spirit and this "living thing."

The Shinshu distillery is located on a mountain at an altitude of approximately 800 meters, and the environment here has two main characteristics:

1. Significant Diurnal Temperature Variation

This is the most crucial point.

During the day, as the temperature rises, the whisky inside the barrel expands and vigorously penetrates the pores of the oak. In this process, the whisky extracts various flavor compounds from the wood, such as vanillin (bringing vanilla notes) and tannins (providing structure), and its color also deepens. This is like the barrel "exhaling."

At night, as the temperature drops sharply, the whisky contracts due to the cold and withdraws from the wood pores, bringing back all the flavor compounds it captured during the day. This is like the barrel "inhaling."

Because Shinshu is in the high mountains, this temperature difference is much greater than in lowland areas. It's as if the barrel's "breathing" motion is particularly intense, with both the depth and frequency of each "breath" amplified. The result is that the interaction efficiency between the whisky and the oak barrel becomes very high, allowing for faster and more thorough extraction of barrel flavors, giving the whisky a very rich and complex palate even at a relatively young age.

2. Lower Atmospheric Pressure and Cool Summers

High altitude means thinner air and lower atmospheric pressure. This leads to a lower boiling point for the alcohol, and evaporation becomes more active. In other words, their "Angel's Share" (the whisky lost to evaporation) might be lost more quickly, which to some extent concentrates the flavor of the remaining spirit.

At the same time, while the diurnal temperature variation is significant, Shinshu's summers are not as scorching as, say, Kentucky in the United States. This is another subtle balancing act. It avoids overly rapid maturation due to excessive heat, which could make the whisky rough and overly woody (what we often call "over-oaked"). The cool climate gives the whisky enough time to slowly develop its delicate and elegant ester aromas (such as floral and fruity notes), even while intensely interacting with the barrel.

To summarize:

Shinshu's high-altitude environment acts as an "accelerator" for whisky maturation through its significant temperature variations, allowing for efficient flavor extraction from the barrel. Simultaneously, it applies a "brake" through its generally cool climate, preventing over-maturation and preserving the whisky's elegance and delicacy.

So, when you drink Shinshu whisky, you often find that despite its relatively young age, its flavor is remarkably full-bodied, and its palate is clean and balanced—this is the "magic" bestowed by the high-altitude environment.