Despite all the advances in technology, all the novel botanicals being used and the adventurous flavour profiles being creates, the pot still predominantly remains Gin’s time-honoured companion.
At its simplest, a pot still comprises three main parts: the pot or boiler, the neck or swan, and the condenser. (See article on how Pot Stills work here)
To recap on gin making 101… To initiate the process of making gin, the pot is filled with a base alcohol, also known neutral spirit, water and a choice of botanicals. This “charge” is then heated to start the distillation process.
Pot stills can be heated using several methods, each with its unique influence on the end product. The choice of heating method is probably the most important part of selecting what’s right for you. The primary methods are direct fire, steam heating, and indirect heating through a bain-marie or water bath.
For those interested in starting a gin distillery or looking into equipment for it, this article delves into these in a little more detail.
Direct fire
In the traditional direct fire method, the pot still is heated from the bottom using an open flame. Some are literally log fires in a compartment under the still, others are gas rings.
It’s quick, simple and effective as a heating mechanism and other than managing the safety of having fire near spirit, an easy way to heat the still. Think of it much like an old school kettle on a stove.
Some distillers talk about “the Maillard reaction” – the same process that gives a nice crust to your steak or bread. That having distinct hot spots leads to caramelising certain botanicals. It’s possible, much as it is for a soup in the base of a pan, but it’s unlikely. As and when it happens is either at the end of a distillation run (when the volume of liquid is low), or in minute amounts that it doesn’t affect the flavour hugely.
The reasons for this are simple. Stills are almost never left to ‘run dry’ in that even at the end of a distillation there is still a significant amount of liquid in a pot, and the botanicals are floating and bubbling about. The same goes with when it’s full and not distilling yet. So few botanicals sink to the bottom and once heated, the liquid bubbles (just as it does in a kettle) meaning the few that might don’t scorch and stick the bottom of the pot like a bit of pasta. For the hybrid german stills that still have wood inlets, many of them have agitators stirring too…
For those looking into this method key things to remember are:
How are you isolating the fire safely in day-to-day usage to avoid any possible contact with spirit.
What are your hard stop safety protocols. Look at your access to gas shut off valves, your fire suppression protocols etc.
If using gas canisters, are you legally allowed to store them in the same space (some countries ban this), the size of them (how many distillations per canister etc.).
Steam heated pot stills
Steam heating is a popular modern method where steam is injected into coils inside the pot, or more frequently, coils that are in a jacket that surrounds the pot. This provides a more evenly distributed and easily controlled heat source than direct fire.
This method eliminates the risk of open flames and allows for a more consistent distillation process. As the coils wrap around the pot, the heating process is universal and allows significant control for gin makers looking to change the tempo of their distillation.
This fast paced reactive control you can have over it is an added advantage for more experienced distillers use to iron out any irregularities going on.
For those looking into this method key things to remember are:
The boiler needs to generate steam! There are legalities of ventilation flues, access and separation (some councils must be in a different room to the still) in many countries. It’s not as simple as having an electric input. To make steam you need water too, which is often pre-treated.
Pressure requirements and pipework to feed the still need to be factored in. Know what you are generating vs what you need to supply the still as often there are custom fixes that need to be made to buffer input.
Indirect heating: Pot stills in Bain-Marie (water baths)
The third method is the bain-marie or water bath, an indirect form of heating. This technique involves double-walling the pot still and filling the space between with hot water circulating, or placing the entire pot still in a larger, water-filled vessel.
When heated, the water bath provides gentle and uniform heat, making it an excellent choice for those wanting to take a slow approach. Not only does it allow precise temperature control over a big surface area, it also instigates changes very gradually – ideal method for gin distillation.
Electric heating – plates, wraps and coils
Hot plates are common place for small alembic stills. Replacing fire, they heat the still much like a conventional electric kitchen hob. They are practical, safer alternatives to gas rings. Clearly, the limitation there is the size of pot still. Just like you can’t heat a cauldron of soup on a single hob, there is a practicality limitation to electric plates. Simple pot stills up to 100L are feasible.
Another style of still, primarily seen in American moonshine stills, involve a heated coil. Just as you might find in an old kettle, the coil acts like a heating element and its resistance (the material’s efforts to stop electricity flowing through it) turns the electrical energy into heat.
Moonshine stills (direct coil) are terrible for gin
They will scorch any botanical that comes in contact with it and unlike flame heated stills, as the coil is literally inside the pot (not on the outside of the copper) and red hot – it’s highly likely to happen. Pots that have them are harder to clean, and the distribution of heat is not as even (again as there is a singular point right at the heart of the fluid heating the mix, rather than spreading around the still and into the still via conduction). Avoid them at all costs if gin making is your intended primary spirit.
Just as there are steam jackets, it is possible to have electrical equivalents integrated onto the outside of the still. Most known manufacturers will be able to do this and most will set it up as a series of rings around the still, each with their own on / off switch, allowing for great control over the pot, amount of power used and distribution of energy.
For those looking into this method key things to remember are:
Atex ratings or equivalent local legislation for electrical equipment allowed around pot stills.
The size of pot, the time it takes to heat and the associated running costs. It may be more efficient and cost effective to switch to steam for units larger than 400L.
How to pick the right gin still for your distillery
The choice of heating method is an intricate part of the distiller’s craft, an important tool to coax out desired flavours and characteristics. Each distillery might favour one over the others based on their preferred balance of tradition, control, and flavour outcomes.
Obviously, a lot of selecting which is suitable comes down to cost, but there are some useful questions to consider:
What can I legally do and get approval for?
Not all countries will allow all the above methods of heating.
What are the distillery footprint restraints?
If you need a steam boiler isolated in a separate room, that takes space. If you have a micro operation, pipes and wires across a multi-use space are not ideal…
Ask yourself if you are working with natural ventilation, walls, or open plan etc.
What is the best energy input source available to me?
Some will not have access to a steady supply of electricity. Some may have a renewable source close by. Others may want to avoid high unit rate costs and tap into alternate fuel sources like biomass boilers. Ask yourself what are the carbon implications of your chosen method and how you are factoring in sustainability.
What size is my ideal pot and how do I work backwards?
Larger pot stills will consume significant electricity to heat. This means that while electric stills might involve cheaper set up costs, running costs will quickly rack up. Some big pots will perform very poorly if only electrically heated due to power constraints too.
Meanwhile, pots over the size of 500L will take considerable extra space if you are looking to use a Bain Marie etc.
What kind of other spirits beyond gin are you making?
If making more than gin, other spirits may have a different tempo of distillation where low and slow will be a waste of time and resource. Equally, there may be the need for other use power elsewhere to factor in, such as heating mash etc.
Not only will there be other opportunities for savings using equipment like heat exchanges, calculating the total requirement is important. That varies greatly depending on the spirit and process each requires.
What do you feel comfortable with using safely and consistently?
So much of making high quality gin comes down to the person, not the machine. What suits the distiller is paramount to consider. Equally, so much of good safety protocols come down to process and procedure implemented daily, in addition to the inherent system design.
It is vital that the choice suits those working with it daily, that they understand it fully and are consistent in their approach to it each day.
Many factors amount to creating the right choice
The choice of heating method for pot stills in gin-making is a crucial aspect of the distilling process. Each method, whether direct fire, steam heating, indirect heating, or electric heating, has its unique impact on the distillation process and the final spirit.
Distillers must consider various factors such as safety, cost, legalities, distillery size, and desired flavour profiles when selecting a heating method.
The decision ultimately reflects a balance between tradition, control, and innovation, influencing the quality and character of the gin produced.
