Whiskey Nips: The Column Still
The method for early distillers to make alcohol was to use a pot still for distillation. The way a pot still works is that the liquid mash inside is heated up and boils off the alcohol, turning it into vapors. The vapors then travel through the neck of the still into smaller tubes surrounded by water which cools the vapors back into liquid. This process means that the distillate that is produced is done in batches. You put the mash in, heat it up, and distill the alcohol off. Just like Grandma’s delicious oatmeal raisin cookies, the batches will vary, resulting in an inconsistent product if you are not an expert. To remedy this problem, you can combine the different batches to a taste profile that you are looking for. But not all the alcohol makes it out. This means you also have empty, clean, and refill the pot still. It is very labor intensive and inefficient.
In response to the inefficiency, a new method of distillation came about in 1831, when Aenas Coffey patented the “Coffey still” in Ireland. This still is designed as a large vertical column, where it is no longer distilling in batches and can distill continuously, hence the name column or continuous still, which it is usually referred to as. The mash enters the column while steam is boiling up from the bottom. There are a series of chambers of plates throughout the column which have little holes for the mash to fall down closer to the heat, and rise back up as they boil off. The vapors start off low in alcohol concentration, because alcohol has a boiling point of 173.1°F in comparison to water which is 212°F, but the temperature lowers as the vapors rise through each plates and the water will keep falling down turning back into steam, resulting in a more alcohol condensed vapor.
This revolutionized the whiskey industry. The Coffey still was quickly adopted by many distilleries because they were able to operate at a higher efficiency, lower their operating costs, and create a more consistent product. However, there are some who prefer pot still distillation because they feel that it results in a much richer and full bodied product. There are a few distilleries that promote their pot still distillation as a superior method, but I have had great whiskies from both types.