It’s become clear that after years of talking about the low-temperature distillation in our spirits, it was time for a deep dive into the world of distilling.
Let’s start from the beginning.
What is distillation?
Distillation is a breakdown of sorts, a method that allows liquid mixtures to separate into their components. Although we think of distillation as the necessary step to create the spirits we love, this process is applied to many industries, from petroleum production to your favorite perfumes and even large-scale water purification.
How does it work?
It all comes down to heat and pressure. To better illustrate the process, let’s focus on booze.
To produce a spirit, you need to concentrate your alcohol by separating it from water. For grain-based spirits, you start with a wash (almost like a beer) and separate the ethanol that is created during fermentation (alcohol) through distillation. Different compounds have different boiling points; ethanol’s is lower at 78°C (173°F) than water at 100°C (212°F). As a result, if you heat your still up at 78°C (173°F), your ethanol will become vapor before your water boils. It is then brought back to liquid form by cooling it down using condensation. And there you have your alcoholic distillate. This is how it has been done for centuries.
And when we say centuries, we may look as far back as the Bronze Age. Used for ritual purposes across the globe, its purpose shifted to medicinal use in the late 13th century in the form of Water of Life or Aqua Vitae in Latin. And from what could frankly be called poor-quality distillates, technological advancements, and better raw ingredients led us to the spirits we now drink and the categories they fall under. Yet the techniques have remained the same throughout the ages.
Of course, traditions are a beautiful testament to one’s region and history. Keeping them preserves cultures and practices. But some questions kept on bugging us when we started Empirical:
“What about novelty? Why not move beyond what we know and the categories that have been established centuries ago? What is the future of flavor and spirits?”
These questions are what pushed us to deconstruct our knowledge to reassemble it anew.
Moving to vacuum distillation
Working with various methods of fermentation to create a flavor matrix and then a wide range of delicate botanicals, we felt that distilling with heat was denaturing the esters formed during fermentation; but also ‘cooking’ some ingredients we’d rather prefer fresh, and not providing the flavor experience we wanted to share.
We therefore turned to vacuum distillation. Primarily used in the pharmaceutical and perfume industries, vacuum distillation drastically reduces the boiling point of solvents you wish to distill, thus preserving all the fresh volatile flavor compounds of the ingredients.
Comparing traditional distillation with its vacuum counterpart is like putting marmalade beside freshly pressed orange juice, the two being different expressions of an orange.
But how does it work? Boiling points are variable depending on the pressure present in your still. As we go under a vacuum, we reduce the pressure to almost nonexistent, thus reducing the boiling point. It’s basically like boiling water at cruising altitude. This means that we can distill our ethanol by heating it as low as 9°C (48°F). We usually heat at an average temperature of 20°C (68°F), room temperature if you like, meaning that all the flavors remain intact, just as you tasted them fresh. It also allows us to isolate all the distinctive flavor notes showing up at different points of the distillation to then blend them to our desired profile.
What are volatile compounds and why do they matter?
Have you ever thought of what makes smell and flavor happen? It’s all in the volatile compounds, which are essentially chemical compounds with a fairly low boiling point making them able to vaporize at room temperature. Since these substances are very heat sensitive, keeping low-temperature extraction is paramount to preserve the esters, aldehydes, alcohols, and other flavorful compounds they contain.
To better exemplify, let’s look at a specific ingredient. Some of you will remember we made a very subtly-named spirit with habanero chilis. But what you may not know is that it takes 215 specific compounds to combine and create the complex flavors of this unique chili. Each of these compounds has a different molecular structure, weight, and inherent flavor and aroma. The lighter ones tend to be more fruit-forward and will be the first to vaporize when distilling, the heavier ones, with earthier flavors, follow one by one. Some are however too heavy to go through distillation and are left behind. This is the case for capsaicin, the piquant active component of chili peppers. And this is why our habanero spirit had all the flavors of the chili without the burn.
Since these different flavor compounds show up at different stages of the distillation process, dividing our distilling run into the traditional three 4 parts (foreshots, heads, heart, and tails) was not sufficient. Saying that we stretched it would be an understatement.
We segment the alcohol as it comes out of the still in 100 to 200 cuts. This is not just to make life harder for ourselves but to give us full control of the flavors. It is like dissecting a whole into all its distinctive parts. Taking these many fragments allows us to isolate each flavor nuance and volatile compound in our botanicals.
After distillation, we taste each of these cuts, select the ones that best express the flavors we are seeking, and blend them accordingly. One could say it’s a little bit like photoshopping flavors. The ones that do not make the cut (wink, wink) are then used in the next batches or become a completely new product.
Once our selected cuts are blended, we end up with a fairly high 65% ABV. To reach optimum flavor expression, we proof it down to our desired ABV with reverse osmosis water and sometimes distilled kombucha or vinegar.
And this is how we do it! We constantly tweak our equipment and methods to make each new batch even tastier than the last. But that’s another story to tell.