ACID’S FUNCTION IN FLAVOUR CREATION
Let’s jump straight into what acid actually does in regard to flavour creation. Acidity, unlike sugar or salt, has no flavour-enhancing qualities of its own when used in isolation of other taste elements. If we were to add some acid to say, a strawberry, we wouldn’t enhance the natural strawberry character in any way, we would simply make it taste more sour. For acid to be a truly effective booster, it has to be used in conjunction with sugar. Like all of the taste elements, acid has a reductive capacity on the others, so when we combine it with sugar, or any sweetener, it will reduce our body’s ability to perceive the sweetness by balancing it out and allowing for the sugar to conduct its primary function of enhancing those flavours. Sour ingredients also bring their own unique, vibrant, and uplifting qualities to the taste and flavour profiles of our cocktails. Different acids display differing taste properties, so understanding the role each one can play and when best to use them is key to mastering the application of this curious and complex element.
CITRUS - THE SULTANS OF SOUR
Acids are found in pretty much every fruit or natural product we use on the bar. While our use and understanding and use of different acids have come a very long way in recent years, there is still one family of sour ingredients that is the undisputed king of acids: citrus juice. From the earliest Punch recipes, through the first Golden Age of cocktails, where most of the categories we still use today were born, and right up to the present day, they have been ever-present in cocktail recipes in every corner of the earth. And, as such, I’d go as far as to say there’s a compelling argument that lemon and lime juice are the ingredients that have shaped cocktail history more than any other. There’s good reason for their appeal as well. From a taste perspective, citrus juices are the perfect natural souring ingredient. They have high acidity and a low sugar content, making clean, fresh, and sharp. Their fruits grow abundantly in many climates meaning availability is rarely an issue. And what flavour they do contribute – lemon juice in particular – is generally light, bright, and pleasing. However, for all its positives citrus has negatives as well. First of all, citrus juice is notoriously inconsistent. Where we get lemons or limes changes with the seasons, so at certain times of the year they will come from Italy or Spain, and other times from Argentina or South Africa, and their country of origin will have an effect on the fruit’s flavour and acidity. The juice is also highly susceptible to oxidation, meaning that as it is exposed to oxygen in the air its flavour will change and eventually spoil. This has the undesirable consequence of poor-tasting drinks and lots of wastage, two things we very much want to avoid when making cocktails. Finally, even though its flavour is on the whole pleasant – when mixed and balanced with sweetness – it undeniably has a flavour of its own. This means that when we use it in drinks its flavour will come through whether we want it there or not. This can limit the possibilities of flavour creation, as we have to factor in that citrus character to the final profile of whatever ingredients we are pairing.
When I first stepped behind the bar in the early 2000’s we were around a decade or so into the second Golden Age of cocktails. While the signifiers of this new era were a dramatic increase in the quality, volume, and availability of mixed drinks around the world, the style of these drinks – Daisies, Sours, and Swizzles for example – and the techniques used to make them – shaking, stirring, blending, etc. – remained much the same as the first. We were also still left for the most part with that same binary choice of acidifiers: lemon or lime. This began to change around 2007 as we saw the emergence of a peculiar phase in the modern cocktail culture called ‘molecular mixology’. The period was characterised by more modern techniques and equipment – mainly borrowed from progressive kitchens and chefs, as is so often the case with flavour-led innovations – finding their way into mainstream cocktail bartending. All manner of wild and wonderful technical advancements were made in a very short period of time as we began to further understand cocktails and flavours on a molecular level and the impacts of these discoveries were seen across nearly every sector of cocktail culture. Some of these trends – looking at you, spherification – were only around for the blink of an eye. Others – such as the use of rotovaps and other hi-tech pieces of equipment – live on in the top 1% of cocktail venues where they have the expertise to operate them (and the finances to afford them). But the long-term legacy of molecular mixology, and one that is rapidly growing still to this day, is the increased understanding and application of acidic compounds.
The bar which really brought this to the attention of the broader drinks industry was undoubtedly White Lyan[EM7], founded by Ryan Chetiyawardana and Iain Griffiths in Hackney, London, in 2013. The multi-award-winning venue was truly ground-breaking on numerous levels: they operated a near complete zero waste policy, they pioneered pre-batched cocktails, but possibly the aspect they are best remembered for is the complete absence of fresh citrus of any kind across their menus. While they sadly shut their doors in 2016, White Lyan’s influence can still be seen across the industry and perhaps no more so in how we collectively approach acidifying our cocktails. The growing commercial availability of synthetic compound acid powders, such as citric, malic, or tartaric, are allowing bartenders to acidify their drinks without the use of citrus juice. This allows for far greater diversity of flavour profiles available to the bartender as they are able to add sharp complexity and amplification of their flavours without the citrus character that comes from using fresh juice.
DIFFERENT ACIDS AND WHERE TO FIND THEM
Much like the sugars we discussed in my last article, different acids will display different attributes when it comes to both the intensity of their acidity and how long that acidity will last on the palate. It is important to understand this because, like with sugars, we can often achieve the best results when we blend different acids to maximise their singular qualities. Once again, we have the wonderful Stu Bale and his team at Crucible London to thank for the data and the graphics. All samples were measured at the same pH level, with the graph showing perceived sourness, and how long that sourness lingers for.
The obvious place to start here is citric acid. It has a relatively high level of sourness, but it is surprising to see that its taste will dissipate quickly. It has a distinctive zesty vibrancy to it with a sherbety fizz and tingle. While it is of course the primary acid in lemon and lime juice, as well as orange and grapefruit juices for that matter, it is also found in high concentration in many berries and tropical fruits such as pineapple.
Malic acid has both a high level of acidity and an incredibly long-lasting finish. It is found in nearly all fruits in some concentration but it particularly apparent in apples, pears, and peaches, but, as these fruits generally contain high levels of sugar, to fully feel the benefit of its punchy freshness it is best used in powdered form.
Tartaric acid is the primary acid found in grapes and is therefore found in most wines and vermouths. It has a relatively brisk yet mild sharpness but can be used to add a harder edge to a sourness profile.
Lactic acid is rarely used in cocktails because of its comparatively low acidic flavour, but it is an important one to be aware of, primarily for its effect in the trending category of Milk Punches as it is found in dairy products. When used correctly, lactic acid is typified by a creamy, mouth-filling sharpness that is more textural than other acids. It is also the primary acid in sour beer, another trending category that is growing in popularity as an ingredient in mixed drinks and is produced in the production of fermented foods such as sauerkraut and kimchi. Champagnes which undergo malolactic fermentation (the conversion of malic acid into lactic acid), will also contain this acid and display a creamy, biscuity profile.
Ascorbic acid, better known as Vitamin C, is found in a wide range of fruits and vegetables and is the second most concentrated acid in citrus juice. It is also a powerful antioxidant, meaning that when added to freshly-squeezed citrus or any fruit juice it can preserve the flavour and colour, thus extending the shelf life significantly. Due to its relatively subdued sharpness but longer-lasting taste
Acetic acid, another produced primarily through fermentation, is best known as the acidic component in vinegars. While it has a long and complex taste profile, it also has a pronounced and distinctive vinegar flavour that can be problematic for most drinkers. For this reason, its best application is for pickling ingredients or garnishes, [EM11]or in flavoursome shrubs, rather than as an acidifier in its own right.
COMPOUND ACIDS = COMPLEX CORDIALS
As we can see, different acids have their own unique qualities that lend themselves best to certain styles of drinks or choices of ingredients. How we choose to use them is entirely up to the individual, but for practicality’s sake and to ensure consistency, when using compound acid powders, it is best to prepare them in a liquid solution of some kind. This can be a pure acid solution, to replicate the role of fresh citrus juice, but in my experience, cordials are by far the best options, and they’re a lot easier to make than you may fear, as long as you have some accurate scales. Cordials are effectively a sugar syrup whose sweetness has been balanced with acids and they are, in essence, the purest example of the flavour-amplifying properties of combined taste elements. They are also an incredibly versatile ingredient as they can be used to both infuse flavours into your cocktails, or as a potent, balanced flavour enhancer to intensify the other elements of them. When making a base cordial, you want to aim for a ratio of somewhere in the region of 14 parts sugar to 1 part acid compound. The best results come when blending multiple acids together, as it’s possible to manipulate the intensity, length, and texture of the sour aspect while still maintaining optimal balance.
My go-to recipe for a neutral cordial base is: 500g caster sugar 500g purified water 15g citric acid 15g malic acid 15g tartaric acid
LAYERING ACIDS AND THE MAESTROS AT HAWKSMOOR
While cordials are your best option for using compound acids to make a cocktail ingredient, the best cocktails are ones that layer multiple different acidic ingredients together. By combining different acidic components, both fresh and compounded, we create not only rich and complex flavour profiles, but also intriguing and long-lasting taste and texture sensations, and someone who knows a thing or two about making sensational cocktails is Liam Davy, Bars Director for the world-famous Hawksmoor Group. Liam’s approach to cocktail making combines traditional practices with modern techniques, and his new menu – one of the best I’ve ever seen – embodies these principles perfectly, with a playful and intriguing section dedicated to 90’s classics that have been revived and reenergised with contemporary twists. The standout drink in my opinion, and one which exemplifies the practice of layering acids, is the Odessa Spring Punch, a revamped homage to the late, great Dick Bradsell’s iconic Russian Spring Punch. The serve comprises vodka, a sweet-sharp damson liqueur, blackcurrant shrub made with rice vinegar and elderflower cordial, fresh pressed lemon juice and Champagne, and the result is a true sensory masterpiece. Aside from the vodka, each ingredient displays the qualities of a different form of acid, and each somehow manages to stand out in its own right while seamlessly blending with the others. It is a shining example of thoughtful, impactful, and masterful understanding of how and when to use sour ingredients.
Combined with savvy sugar handling, clever use of acids not only delivers well-balanced cocktails but more importantly brings brightness and freshness, while also delivering intriguing taste and textural qualities. Next time we’re going to look at bitterness and see how this too-often misunderstood taste element is best harnessed in mixed drinks.
———— The views and opinions expressed in this article are those of the author and do not necessarily reflect those of Freepour.