This article delves into the intricacies of pot distillation.
As you’ll discover, pot still distillation is not just a process; it’s a legacy of craftsmanship passed down through centuries.
We’ll explore how pot stills shape the character of your spirit, what processes and equipment are essential, and what variables need your attention.
A quick history and evolution of pot stills
The journey of pot stills from ancient alchemy to modern distilling is a fascinating tale of innovation, experimentation, and cultural evolution.
The origins of distillation trace back to ancient civilisations, where rudimentary distillation was used for making perfumes (rose water) and medicinal concoctions. Early distillation apparatuses were basic, made from clay or glass.
The Alembic still, one of the earliest forms of distillation equipment, was used by alchemists in the Middle Ages. This device, featuring a pot and a cap with a downward tube for condensation, laid the groundwork for modern pot still designs.
The transition to copper was a pivotal moment in the history of pot stills. Copper’s excellent thermal conductivity and its natural ability to remove sulphurous compounds made it an ideal material for distillation. Let alone it’s malleability to be crafted into the shapes required.
As distillers realised the positive impact of copper on spirit quality, the material became synonymous with high-quality distillation.
Evolution in design and understanding
Over the centuries, the design and understanding of pot stills evolved significantly. The shape and size of the still began to be seen as crucial factors influencing the spirit’s character. For instance, taller stills with longer necks produced lighter, more refined spirits, while shorter, wider stills yielded richer, fuller-bodied spirits.
This understanding, combined with a dramatic shift in spirits being consumed recreationally rather than just for medicinal purposes, prompted distillers to experiment with various still shapes to create distinct flavour profiles.
Additionally, the science of distillation was refined over time. Distillers learned to control the heat applied to the wash more precisely, affecting the rate of distillation and the quality of the spirit. They also started to understand the importance of the different phases of distillation – the ‘heads’, ‘heart’, and ‘tails’ – and how to make precise cuts to extract the best quality spirit.
Technological advances
The Industrial Revolution brought further advances. The introduction of steam as a heat source allowed for more even and controllable heating, reducing the risk of scorching the wash and fiery breakouts.
Today, modern distillers blend traditional techniques with contemporary knowledge and technology. Innovations in still design continue, with micro-distilleries experimenting with unique shapes and configurations, pushing the boundaries of flavour and character in spirits.
Why is all this relevant today?
Understanding this rich history helps modern distillers appreciate the depth of their craft. Its relevance goes beyond just producing alcohol.
The evolution of pot stills is not just a technical progression; it’s a cultural and artistic journey that distillers are a part of, carrying forward a legacy that shapes the very essence of the spirits they create.
The mechanics of pot distillation
Pot distillation is both an art and a science.
The process starts with heating a fermented liquid (wash) in a copper pot. As the wash heats, alcohol and other volatile compounds vaporise. These vapours then rise and enter the condenser, where they cool and revert to liquid form, known as the distillate.
The non-volatile substances, including solids, are left behind in the pot. This process is not just about separating alcohol from the wash; it’s about capturing the essence of the flavour. The key to do both therefore, is to manage the heating carefully, ensuring a steady and controlled distillation.
Types of condensing systems
Worm Tubs
The worm tub system is a nod to the traditional method of condensation. It consists of a spiral copper coil (the worm) submerged in a tub of cold water. As the vapour passes through / down the coil, it cools and condenses. This method, while steeped in tradition, poses challenges in maintenance and efficiency.
Shell and Tube condenser
The shell and tube condenser represents modern distillation’s technological advancement. In this system, vapours pass through a series of tubes surrounded by cold water.
This setup allows for more efficient and consistent condensation of the vapours, resulting in a cleaner spirit. Most don’t think of condensers as having an impact on flavour creation but as they influence mouthfeel and offer different amounts copper contact, they definitely play a role in the process! The shell and tube design also makes it easier to maintain and control, offering distillers a more reliable and efficient means of capturing the essence of their spirits.
Depending on the manufacturer, you may not get a choice in picking one or the other but with that said, understanding these condensing systems is still useful.
When working with a pot still (or buying one for a new distillery) it’s about selecting a process that aligns with your vision for your spirit and the story you want it to tell – from the size of pot, the shape, height and details in the neck, the lynne arm angles and the condenser. The combination should be considered simultaneously.
Whether you lean towards the tradition of the worm and worm tub or the efficiency of the shell and tube condenser, it’s a reminder that each still is the sum of all the parts and nothing is just a component that exists. The entire configuration will affect the flavours you create.
Impact of still design on spirit character
Shape and size considerations
The design of the pot still significantly influences the final spirit character. Taller stills with long necks and lyne arms promote reflux, leading to a lighter spirit, while shorter, wider stills allow more heavy compounds to pass through, resulting in a fuller-bodied spirit.
The surface area of the copper also plays a role in the interactions during distillation, with bulbs, spheres and angular shapes in the necks all influencing internal pressure and reflux too.
Temperature and pressure management
In pot distillation, temperature and pressure control are crucial for achieving a consistent and high-quality product. The boiling point of the wash must be carefully monitored and maintained.
Too high a temperature can impart unwanted flavours (when making certain spirits) as well as increase the rate of distillation to quickly (which will affect both flavour and possibly yield), while too low a temperature may result in an inefficient distillation and added costs through energy use and time spent. Pressure control, while not as critical in pot stills as in column stills, still plays a role in ensuring a steady and controlled distillation process.
How it’s heated, and the distribution of heat is a big factor to consider.
Sustainable practices
Sustainability in distillation is becoming increasingly important and pot still designs are changing as a result. Innovative distillers are exploring ways to reduce their environmental impact, such as using renewable energy sources for heating (as well as complex heat exchangers for secondary use of the heat generated), insulation jackets and more.
Direct or side-mounted plate systems
Some pot stills are equipped with either direct mounted plates or side mounted columns that allow for a degree of rectification, increasing the alcohol strength and purity of the distillate. These variations offer distillers more tools to tailor their spirits to specific flavour profiles and styles.
Pot stills & two-stage distillation process
The two stage process is common for those using pot stills to make Whisky and Brandy.
Understanding how it works helps you appreciate the effort it takes to make world class spirits and how much of it is people working with their stills to create a desired outcome, rather than a machine you can automate.
First stage (wash distillation)
The first part of the two-stage pot distillation process sets the stage for quality spirit production. Here, the wash, which is a fermented liquid containing alcohol, is heated in the pot still.
The primary goal at this stage is to separate the alcohol and volatile flavour compounds from the water, solids, and non-volatile components. Flavour creation always a goal, but the emphasis is on raising the ABV and separating out the water.
It’s typically a distillation that can be described as “running the stills hard and fast”. Which in distilling terms really means steady and controlled, with strict parameters and predictable, repeatable process (but you get the idea).
The distillate collected at the end, often called ‘low wines’, is far stronger than the wash. However, it has a lower alcohol content compared to the final product and requires further refinement.
Second stage (spirit distillation)
The second stage, or spirit distillation, is where the distiller’s skill truly shines. The ‘low wines’ from the first stage are re-distilled.
During this process, the distiller carefully separates the distillate into three parts: the ‘heads,’ containing undesirable, highly volatile compounds; the ‘hearts,’ which is the desired portion with the ideal balance of flavours; and the ‘tails,’ containing heavier, less volatile compounds.
The timing and precision of the cuts between the heads, hearts, and tails are fundamental in defining the spirit’s character. Early cuts can capture more of the lighter, fruitier compounds but risk including unpleasant elements from the heads. Late cuts, meanwhile, might result in a richer, heavier spirit but can introduce undesirable flavours from the tails. Each spirit type has its ideal balance and each still will dictate the timing of these compounds reaching the distillate flowing off the spout.
Achieving consistency in cuts is one of the most challenging aspects of pot distillation. Experienced distillers rely on a combination of temperature monitoring and sensory evaluation to make these decisions.
Consistency is vital for brand identity, as customers expect each bottle to match their previous experiences.
Advice for new distillers
For new distillers delving into pot still distillation, here are the five most pertinent tips to focus on while you get started on your journey.
Understand the importance of copper:
Recognise the unique properties of copper in pot distillation. Copper not only conducts heat efficiently but also plays a crucial role in removing sulphur compounds and other impurities, leading to a smoother and more refined spirit.
Familiarise yourself with the maintenance and care of copper stills to ensure optimal performance and longevity.
Master the art of cut points
The separation of the heads, hearts, and tails during distillation is critical for defining the quality and flavour of your spirit. Learning when and how to make these cuts requires practice and sensory acumen.
Pay attention to changes in the flavour and aroma of the distillate, and don’t hesitate to rely on both instrument readings and your senses. Learn how yours behaves, changes and flows.
Control temperature precisely
Temperature control is vital in pot distillation. Too high a temperature can lead to undesirable flavours and not enough reflux, while too low a temperature may result in inefficient distillation.
Invest in reliable temperature and flow monitoring equipment and learn to make adjustments as needed to maintain a consistent and appropriate temperature throughout the distillation process.
Choose the right equipment for your spirit
The design and size of your pot still can significantly influence the character of the spirit you produce. Taller stills with longer necks generally produce lighter, more refined spirits, while shorter, wider stills yield a fuller-bodied product.
Your choice should align with the type of spirit you aim to produce and the flavour profile you desire. If you are working on a still already, use this knowledge to understand what the still will naturally want to deliver so that you can work backwards from there to your desired outcome.
They are not being flippant or joking when distillers say that each still has a personality…
Embrace experimentation and learning
Pot distillation is as much an art as it is a science. Be open to experimenting with different techniques, such as adjusting fermentation times, trying various yeast strains, or altering the wash composition.
Continuously seek knowledge through courses, industry literature, and networking with experienced distillers. Remember, every batch is an opportunity to learn and refine your craft. That mindset separates the best ‘master’ distillers from the journeymen.
As the craft distilling industry evolves, pot distilling principles remain foundational, guiding distillers in creating spirits with distinct personalities and stories.
It’s a craft that has been around for centuries. Through mastering temperature and pressure control, the impact of still design and the integrating sustainability innovations, distillers can ensure their spirits not only taste exceptional but also carry forward the rich legacy of pot distillation.
This was a general article about pot stills overall. For those wanting to read more. we have pot distillation Insight for Whisky, Rum and Brandy – delving into the specifics of those spirits.
