So, what exactly is a vapour chamber and how is it related to gin? Put simply, a vapour chamber is a specialised part of a still where you can suspend botanicals. It plays a big part in contemporary gin production, but the equipment and technique has been used for centuries…
From a gin maker’s perspective the vapour chamber, also known as the botanicals chamber, botanical basket (and often wrongly, the Carter Head but more on that later), offers a unique chance to infuse some of the more delicate flavours that would not survive being heated in the pot.
Here’s everything you need to know and some extras for good measure!
The gin distillation process
In traditional pot distillation, botanicals are steeped in the neutral spirit, much like you do when infusing loose leaf tea at home. The still is then heated and distilling begins.
In contrast, the vapour chamber method, or vapour infusion, sees these botanicals suspended in a perforated basket within a chamber typically much higher up the still. As the spirit vapour rises, it permeates through botanicals, extracting the oils and flavours on its whimsical journey.
What does this mean for your gin?
Steeping can sometimes produce a bold, intense profile, while vapour infusion tends to coax out the gentler, more aromatic nuances of botanicals. But for those interested in digging a little deeper you’ll find that it’s not as simple as the spirited version of steaming vs boiling an ingredient.
The unique aspects of the vapour chamber distillation method provide several benefits that help define the character of a gin. Here are three key benefits:
Protection of delicate botanicals
You don’t need to boil a cucumber to know that less heat is better for certain botanicals. Vapour infusion exposes botanicals to the spirit in vapour form rather than direct contact with the liquid.
This helps protect more delicate botanicals that might otherwise degrade or change character entirely under the intense heat of traditional distillation. This is why botanicals that have delicate floral or citrus notes which are best expressed without direct exposure to high heat are placed in the basket.
Predominant infusion / extraction by higher alcohols
Distillation 101 – The pot of a still is filled with ethanol and water. As distillation begins, the vapours to emerge separate the two, with alcohol rising first.
Botanicals that macerate in the pot are infused at the ABV the distiller chose to start with (typically 40-50%). Botanicals in the vapour chamber only encounter the vapour that’s been distilled. Depending on the still, this will begin in the high 80’s and by the end of the heart’s cut, will not be likely to be lower than 50%’s.
That’s a much higher ABV bandwidth to be exposed to.
This matters as the compounds extracted by water are different than by high ABV ethanol. Savvy gin makers use this to their advantage! The combination of lower heat than the pot and higher ABV exposure allows for the development of unique and complex gin recipes.
Combination of pot and vapour chamber
Some producers use exclusively use the vapour chamber for all their botanicals, such as the legendary Bombay Sapphire.
It’s not a binary choice though – you can do both. Many distiller’s with modern, hybrid stills use both pot and vapour chambers in combination. They might put the juniper, coriander and heavier botanicals in the pot, and layer the lighter herbs and fresh peels in the chamber.
Vapour chamber vs Carterhead
A vapour chamber is often associated with the term ‘carterhead’. They are not one and the same though. While a vapour chamber is a component that can be used in various types of stills, a Carterhead still is a specific design of still that includes a vapour chamber in its configuration.
Carterhead stills were a patented design that have been in use since the 1800’s. That patent specifies many items, such as a direct mounted column that has plates within it. There’s even a cooling jacket at the top to force reflux.
There are angles, measurements, and as you’d expect something engineered to a point where it could be patented – they are very complicated.
The vapour chamber is the part that captures the imagination. Moreover, because Bombay Sapphire (who have actual Caterhead stills) used the term extensively in marketing campaigns to explain their (at the time unique) process, the two became intertwined.
Then Hendrick’s also joined the chorus of big brands extolling the virtues of their Carterhead (they were also correct in saying this as they use actual Carterhead stills). The key message that was being communicated was simplified – that vapour infusing botanicals is the same as using a carterhead. The terms became jumbled.
Knowing that the two are different is a pedantic as it gets. But it’s important.
At the time of its invention, the Carterhead still was revolutionary. It was invented by the Carter-Head brothers in the mid 1800’s. They began their careers as apprentices to Aeneas Coffey, the famed inventor of the continuous column still.
The intention behind it is important too – Carter-Head still was most likely originally designed to rectify the poor-quality base spirit. A fact not lost on William Grant, who use a carterhead in the production of Reyka Vodka… This extra copper contact maybe unnecessary in gin today, but it serves as a timely reminder that the vapour chamber isn’t just about heat and “steaming” lighter aromatics. It’s also about controlling the condition and the moment spirit comes into contact with the botanicals in the first place.
Lumping the two terms together as being synonymous is actively unhelpful in acknowledging the pioneering nature of the still design and the evolution of the distilling industry.
Two factors at play – and a world of flavour unlocked.
The world of vapour chambers opens up a universe of possibilities for gin makers. This innovative method, contrasting traditional steeping, delicately extracts aromatic nuances from botanicals.
The vapour chamber also empowers distillers with precision and creativity. It is a great tool for preserving the subtleties of delicate botanicals.
As we can see from the legacy of Carterhead stills, this technique has been around for a while. Understanding the intricacies of vapour chambers is not just about distillation mechanics. Fundamentally, it’s about appreciating distilling evolves and how distillers look to elevate their spirit to its highest potential.
