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The art of fermentation in cocktails

Fungus and cultures may not sound appetising, but fermentation experiments are bringing ‘funky flavours’ to cocktails, SB discovers.

*This feature was originally published in the February 2019 issue of The Spirits Business

Fermentation has always played a huge role in drinks; it’s the process that turns grape juice into wine and creates the alcohol in beer. But now, bartenders are bringing a host of other fermented ingredients behind the stick.

From koji and kefir to homemade wine and vinegar, bartenders are increasingly experimenting with fermentation to create their own unique serves. The process, which is the chemical breakdown of a substance by bacteria, yeast or other micro­organisms, can be used to bring ‘funky flavours’ behind the bar, and it’s a trend that looks set to light up the industry in the coming months.

“Bartenders are constantly pushing the boundaries of their craft,” says Jay Khan, co­founder and head mixologist at Hong Kong venue Coa. “It is just a matter of time before everyone starts fermenting, or at least exploring this age­-old technique.”

The process has always played a large role at the Hong Kong bar, with Khan and his team brewing their own rice beer, lacto­-fermented hibiscus soda, guava mead, ginger beer and mezcal vinegar. However, its Mexican-inspired menu means the bar has become well known for its homemade Mexican ferments – such as pineapple­-based tepache and corn­-based tejuino.

“When we make tepache, the wild yeast, Brettanomyces, available on the skin of pineapples, ferments the sugary liquid into a sour and refreshing end product,” Khan explains. The tepache can then be enjoyed in a variety of cocktails or offered as a non-alcoholic drink for abstainers.

As well as creating a value-­added product for the bar, creations like this extend the life of a pineapple – the skins and pulp left over from juicing make the perfect base for a batch of homemade tepache.

While Khan utilises pineapples to ferment his tepache, while other venues may introduce brewer’s yeast, koji (a type of fungus) or a kombucha scoby (culture) to kick­start the brew.

Made from sweetened tea, kombucha requires a symbiotic culture of bacteria and yeast – a scoby – for its fermentation. When drunk on its own, kombucha has a tart, dry flavour, but it can also be enhanced with fruits and juices, or used as an ingredient in cocktails.

“With kombucha, drinkers have a non-alcoholic drink that pairs well with food,” says David Begg, founder of Real Kombucha. Begg created the brand after sampling kombucha at a friend’s house.

“For my first brew I used some Silver Needle tea that I had lying around and a scoby that I had been given by a friend. The variety of tea can give the same range of flavours as a good wine. It’s now become a passion of mine to try and extract all these flavours from different strains of tea.”

What started in a jar on Begg’s kitchen worktop has since moved into a custom­-built brewery producing three kombucha expressions. “Our Royal Flush is similar to something like a white Burgundy, Dry Dragon could be compared with a Sauvignon Blanc, and the Smoke House has a similar flavour to red wine,” says Begg.


This past year in particular, kombucha has been embraced by cocktail culture. At sustainably minded Sheffield bar Public, passion fruit kombucha is used in its Wee Hector cocktail, which also includes Johnnie Walker Gold Label whisky, crème de pêche, preserved vanilla and Prosecco.

As well as the kombucha used for the Wee Hector, the latest menu at Public also features apple-­core wine, fermented rhubarb and elderflower vinegar – each made in-house. Bar manager Jack Wakelin says: “We turned to fermentation to maximise the potential of ingredients we already had on our menu. With our rhubarb cordial, for example, we’d make the yield needed to get us through two days of service and the leftovers could then ferment for up to two weeks to preserve and use in another drink.”

Public in Sheffield has cut down on waste

The bar’s fermented rhubarb is used in the Force Majeure, which combines Cocchi Barolo Chinato, Ramazzotti amaro, Lillet Rosé vermouth, fermented rhubarb, preserved vanilla and Prosecco; and the alcohol­-free Rhubarb Spritz, which blends fermented rhubarb, preserved vanilla, white wine vinegar and soda.

The bar’s exploration of fermentation also allows it to cut down on waste. Wakelin says: “We try to be as zero­-waste as possible by using these methods, but the overall aim is to try to make the ingredients approachable and appealing to our clientele.”

As well as the draw of creating a more sustainable venue, fermentation can also help bartenders create drinks that their customers can’t find elsewhere. At Operation Dagger in Singapore, the bar creates its own mead, tinctures and wines, including one made with fermented cabbage.
Renowned London bartender Ryan Chetiyawardana has been a pioneer of fermentation since he opened the doors to his zero-­waste bar White Lyan in London in 2013.

That has since closed, but Chetiyawardana’s experimentation with fermentation has continued at his Dandelyan, Cub and Super Lyan venues, and will no doubt also feature at his soon-­to­-open Lyaness in London and Silver Lyan in Washington DC. Chetiyawardana, who appeared at the London leg of the Bacardi Brown­-Forman­-backed Jigger Beaker Glass forum, says: “Initially, I was playing around with wild fermentations in 2008 during my days at [Edinburgh bar] Bramble as a way of creating flavours I couldn’t create myself.”

Since then, Chetiyawardana has experimented with ferments, and the bar teams at his Lyan venues regularly use koji. The fungus breaks down starch in rice and is used at Dandelyan to create its twist on the Hardshake cocktail.

Chetiyawardana says: “Koji is one of the harder ones for places to use without investing into it, but what it adds is great. You can use koji as an ingredient – it’s both floral and rich – or you can use it as a powerful saccharifying [the process of breaking down complex carbohydrates] agent that adds a rich base of amino acids. It’s become key to a few of our most famous drinks.”


While fermentation is great at producing new flavours and innovative drinks, the process comes with challenges. “Consistency, spoilage, off notes and toxins are all potential flags,” Chetiyawardana explains. “As with any processing, safety must be paramount.”

Factors such as temperature, acidity and dilution can all affect the end result of a specific fermentation, says Khan, of Hong Kong­-based Coa. “Your ferment will not always succeed because of many variables, especially in your early days of fermentation. Being patient and persistent will help you in the long run.”

To stay on top of quality, Khan, Chetiyawardana and Wakelin all have the same advice for anyone looking to attempt fermentation themselves – read. “There are so many great resources, that getting started is easy,” says Chetiyawardana. “But start small and try to find something that is relevant to your product.”

Wakelin adds: “It’s the trend on everyone’s lips, and the recent release of The Noma Guide to Fermentation will have a massive impact on the bar industry.”

As fermentation becomes commonplace in the world’s top bars, it may become vital to remember Khan’s words of advice: “If anything smells weird and unpleasant, do not serve it to others.”

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