Okay, so, some of you might have read the last blog post and really wanted to know more about distilling, and some of you are just my mom who wants to support me and pretend to read the new blog post. Well, welcome back and hello to anyone brand new to the site. This particular post will be all about the basics of distillation without getting too scientific - at least I will try!
So what is distillation? Distillation is the concentration of alcohol and flavor/aroma compounds using evaporation. This can be the distillation of a low ABV (alcohol by volume) beverage such as a wine or beer or the redistillation of something that has already been distilled. This whole concept works due to volatility, which roughly means, how easily it evaporates. I know I am throwing some chemistry terms at you but hold on, it’s pretty easy when it’s drawn out:
Figure 1 is an image of a beaker where the blue circles represent water molecules. Now, think about the result of heating the liquid; the water would evaporate. The remaining liquid would still be 100% water and the water vapor coming off would also be 100% water.
In figure 2, the same beaker now has some red circles which represent alcohol molecules mixed in with the water (let's say, 20% alcohol). What happens if you heat this liquid? If things worked exactly like the previous example there would be 20% alcohol and 80% water in the vapor as well as the liquid. But here is where volatility comes in.
Alcohol is more volatile than water. This means it has a lower evaporation temperature and will separate itself in the vapor when heated. That's the rough idea anyway. But as the amount of alcohol in the pot evaporates, more and more water comes through along with it because water is very good at binding to alcohol.
Notice how the vapor coming off at the starting point is actually lower than 50% while the liquid at the ending point is over 50%, even though the starting liquid started at 20% alcohol.
This failure at separation can be rectified by distilling more and more times; you can get closer to that perfect separation. Using that concept, vodka stills artificially create multiple distillations in one piece of equipment to get the alcohol to the right percentage (95%) and the purity to be considered neutral prior to being diluted to 40%. Just think about how tall those columns on the stills are. Each window in this column essentially represents a separate distillation process, helping the alcohol separate from the water. That is also what “distilled X number of times” on vodka bottles refers to. Not separate distillations but the number of sections in their still column.
The job of a distiller for the last thousand plus years is to take advantage of that difference in evaporation and make alcoholic beverages strong enough to put hair on your chest. But there is one thing I didn’t mention before. Along with the alcohol and water in the starting liquid is all the flavor. Every single one of the flavor molecules (esters and congeners) has its own separate volatility. Every distillation concentrates some flavors and gets rid of others and If you go for that pure 95+% alcohol you lose most, if not all, the flavor. Although there is nothing wrong with vodka (and there definitely are differences between vodkas) most people don’t drink it for the taste but as a cocktail with other mixers that supplement flavor.
People that obsess over whiskey, rum, brandy, etc. look for various flavors and mouth-feel that comes from these esters and congeners. Just think how different two bourbons can be from each other in taste or why one wins awards and costs hundreds of dollars while the other costs $10 in the liquor store.
The job for a distiller is not just about making something strong enough to put hair on your chest. They also have to control the concentration and removal of esters and congeners from beginning to end to make the end product as delicious as possible. This isn’t only distillation, but raw ingredient choices, water treatment or non-treatment, fermentation techniques, times, yeast choices, aging, dilution water, and time. A lot of things go into making a good product.