For generations the expression Gin-Clear was a common British idiom. Crystal clear may be the semantically related version we use today, but for many the association between clarity and juniper forward spirits remains absolute.
You can see why. Pour a splash of your favourite classic gin into a glass and look into the clear, transparent spirit.
But times are changing. With hundreds of contemporary additions to the category, you might witness a sudden transformation when you add a drop of water, ice or tonic. There’s often a ghostly dance that takes place as the spirit turns a mystical cloudiness. What was once crystal-clear has now taken on a milky, opaque quality.
This phenomenon is referred to as “louching”.
‘Louching’ is a term that stems from the French word “louche“, meaning dubious or shady. And while there’s nothing dubious about the quality of your gin if it louches, it does cast a very real “shade” or cloudiness over your spirit.
Here’s everything you need to know about it in the context of gin.
How does louching occur?
The answer lies in the chemistry of your gin. The botanicals that give gin its signature taste, especially juniper berries, floral ingredients and citrus peels, contain essential oils and specific compounds that are soluble in alcohol.
When your gin is in its undiluted form, these oils remain dissolved in the spirit, hence its clear appearance.
However, the moment water (be it literal or in the form of ice or tonic) enters the scene, it acts as a disruptor. As the gin reduces the alcohol concentration, the oils and compounds fall out of suspension. They become insoluble, transforming into tiny droplets that scatter light, causing the spirit to take on a hazy, milky aspect.
And voila, louching occurs!
While this effect is usually associated with absinthe, it can occur with any spirit rich in botanical oils, including gin. Louching won’t affect the spirit’s taste, but it will give you an indication of what the gin is made of. The more intense the louching effect, the higher the concentration of botanical oils that have fallen out of suspension.
Louching, while perfectly natural and harmless, might not be desirable for all distillers who want a clear spirit. Commercially, the jury is still out too.
Just as there are those who don’t pick up bottles of olive oil that have clouded on a supermarket shelf – shoppers who don’t understand what is going on in a gin bottle that’s opaque and assume it’s faulty…
Do all modern gins go cloudy?
Not at all. If a distiller prefers to prevent louching in their gin, they can employ the following strategies:
Reduce botanical content. The louching effect is due to the presence of botanical oils. Carefully monitoring the botanical content during distillation could mitigate louching. It’s a tricky balance as reducing the amount of grams you use too much could compromise the gin’s distinctive flavour profile. That said, there are hundreds of gins that have intense flavour profiles that don’t louche, showing that overabundance is often (but not always) the cause. For some, there is unnecessary over-saturation in the recipe and this can fixed / avoided if they desire.
Bottle at a higher proof: Louching is less likely to occur at higher alcohol concentrations. By bottling the spirit at a higher proof, it can retain more of the essential oils in solution. The catch? This could lead to a final product with a higher alcohol by volume (ABV) than is typically preferred by consumers. While it fixes any on shelf louching, it doesn’t solve the issue of what happens when mixed.
Different extraction methods: It’s possible to alter the way you capture the flavours and aromas of some botanicals. It might not be possible for all, across everything, but it can help mitigate the effect.
Cloudiness is different to flocculation
Both louching and flocculation involve changes in the appearance / state of a liquid due to the behaviour of certain compounds. But they are different.
Louching, as we’ve discussed, is a process where the clear spirit turns cloudy or opaque when water is added. To recap – this occurs because the essential oils and certain compounds, which are soluble in alcohol, become insoluble in the water-alcohol mix, thus creating a hazy or milky appearance.
On the other hand, flocculation refers to the process by which small particles suspended in a liquid clump together to form flakes or “flocs”. In the context of gin, this can happen due to changes in pH levels, or the introduction of certain substances in the water (for example calcium or magnesium carbonate, common minerals that occur naturally in hard water) and more.
Flocculation could also occur if there are impurities that have not been removed in the process. Dust in bottles, dirt from natural corks etc. might then clump together and form visible particles.
White calcification crystals, yellow floaties and other forms of brown flocculation are obviously undesirable in a commercial bottling. If you see them floating in a bottle of gin it’s highly likely to be a fault by the distiller and should be returned.
Let’s wrap up!
We’ve demystified the louching phenomenon in gin, and distinguished it from flocculation and explained the science behind it.
The key takeaway is that louching is a natural and harmless process, and merely reflects the high concentration of botanical oils in gin. Whether that bothers you or whether you seek it out is entirely subjective!
