My time as spirits buyer here at K&L is largely spent educating myself not only about our products, but also about how they are made. As I make my way through Jefford's Peat Smoke & Spirit I am learning some interesting facts that I can't believe I hadn't heard before, but maybe that's just because I am so new to this. I'm sure that some of you out there already know about the purifier attached to Ardbeg's spirits still, but for those you you who don't, it's really a fascinating thing. According to Dr. Lumsden, the man behind the process, it is the key to Ardbeg's finesse.
During the distillation process as the alcohol rises, the more contact the alcoholic vapor has with the copper, the more delicate it becomes (scroll down a few posts to the copper still article if you need a refresher). Many stills have what is called a ball or lamp glass shape at the top where the neck widens. This is to create a process called reflux where the vapor gets pushed back down a bit therefore extending the contact time with the copper. Without the reflux effect, Ardbeg would surely be a more robust and savage spirit.
However, Ardbeg goes one step further in this process by having what they call a purifier underneath the lyne arm. This is a pot that is connected by a U-shaped pipe to the arm and it captures the heavier alcohols during distillation. Why is this important? For the first hour and a half of distillation, the lighter alcohols are the primary spirit evaporating from the wash. The heavier ones eventually make it the top as well, but Ardbeg wants more delicacy, so the purifier helps seperate the lighter alcohols from the heavier ones. The heavier ones are then sent back down and reintroduced into the wash. The lighter alcohols have the sweeter and fruitier aromas, which is obviously what separates Ardbeg from heavier malts like Lagavulin. It is for this reason that Ardbeg calls its whiskies two and a half times distilled. Dr. Lumsden has said that without this purification, Ardbeg would be far more one-dimensional.