Does Whisky Have a 'Terroir'?

In Kentucky and Texas, the hot and dry climate means that water evaporates more readily than the alcohol, meaning the overall alcohol content (ABV) can often rise. That means these whiskies are only aged for a few years whereas, in Scotland, the cool and humid weather means alcohol evaporates more readily and the ABV falls gradually with age. These whiskies can lie maturing for decades.

However, there are some curiosities, too. Take the Japanese whisky Karuizawa (with “whisky” spelt the Scottish way, as early Japanese whisky followed Scottish traditions). The distillery, now closed, was located at an altitude of 850m (2,789ft) above sea level on the slopes of an active volcano in the Nagano Prefecture of Japan. Despite year-round high humidity and moderate temperatures, the distillers there appear to have achieved elevated evaporation of water from the casks. That meant a higher proportion of alcohol in the final product – typically well over 50% ABV.

Distillers have understood the relationship between storage temperature and alcohol for some time. Whiskey-makers at a Louisville, Kentucky distillery reported in 1942 that oak barrels could be regarded as "exceedingly poor containers" from a storage point of view due to the amount of whiskey that soaks into the wood or evaporates. Imagine opening a cask after months or years of maturation and finding the vast majority of the liquid gone. But since barrel aging is such an integral part of whiskey production, the distillers experimented with lowering the warehouse temperature and found they could reduce this loss drastically.

Fortunately, whiskey makers today have access to more meteorological and climate data than ever before. Many, including the staff at Balcones, want to use it in to improve the quality and consistency of their products. But distillers, like the rest of us, are also having to adapt to climate change. Data could reveal that rising temperatures and extreme weather are affecting their processes.

Environmental fluctuations can matter even on very short timescales. Himstedt explains that his team uses daily barometric readings to decide how to run their stills, the large containers within which spirit evaporates and condenses post-fermentation. It's essential to "cut", or separate, the distillate at the right time, to ensure that you get just the right volume of volatiles and other desirable compounds in the spirit that will go on to be matured in wooden casks.

from Hacker News https://ift.tt/mnSpQgU