5 Advanced Cocktail Techniques You Should Know

Cocktail making left behind the image of simply mixing drinks a long time ago. Over the past fifteen years we have witnessed a radical transformation that has turned the art of making cocktails into a discipline where science, creativity and precision converge to create unprecedented sensory experiences. At STILLROOM, our signature gastro cocktail bar in the heart of the Jerónimos neighbourhood, every creation that leaves our bar is the result of a rigorous process where advanced techniques are not a mere aesthetic device, but the foundation on which we build memorable flavours.

If you have ever wondered what lies behind a cocktail that surprises you, that makes you close your eyes and think of things you did not know could be combined, the answer lies in these five techniques that have redefined what is possible in mixology. They are not gimmicks or passing fads: they are tools that the world’s best bartenders use to elevate cocktail making to a level that, a decade ago, would have seemed like science fiction.

In this article we are going to explore each of these cocktail-making methods in depth, also known as cocktail preparation methods, explaining not only what they do, but how they work and why they produce such extraordinary results. If you want to go deeper into the technical vocabulary surrounding this fascinating world, be sure to check out our cocktail and mixology glossary.

The technical evolution of modern cocktail making: from mixing to transforming, applied science

To understand where we are today, we need to understand where we came from. Classic cocktail making of the nineteenth and early twentieth centuries was based on precise proportions, quality ingredients and relatively simple mixing techniques: building, shaking, stirring. The goal was to combine flavours harmoniously, extract essential oils from citrus, and dilute the cocktail with the right amount of melting ice.

However, starting in the 2000s, and especially with the signature cocktail movement that exploded in the 2010s, a new era began. Bartenders started asking not just how to mix ingredients, but how to transform the ingredients themselves to create something that did not exist in nature. Could we capture the essence of bacon in a bourbon? Could we turn milk into a clarifying agent? Could we ferment fruit to obtain unprecedented flavour profiles?

The answer to all these questions was yes, and the path to achieving it ran through disciplines that traditionally had nothing to do with bars: chemistry, microbiology, fluid physics. Techniques such as centrifugation, sous-vide infusion, controlled carbonation and freeze-drying made their way into the most innovative bars in the world.

What is fascinating about this evolution is that it has not meant abandoning the classic principles of cocktail making, but amplifying them. A cocktail is still, in essence, a question of balance between sweetness, acidity, bitterness and structure. What has changed is the repertoire of tools available to achieve that balance and, above all, the ability to create flavours that were previously impossible to obtain.

At STILLROOM, we stay at the forefront of this evolution. Every technique we apply has a purpose: to intensify a flavour, to soften a texture, to bring complexity where before there was only simplicity. And in this article we are going to share with you the five that we consider fundamental.

Fat washing: infusing fats into spirits

Fat washing is perhaps one of the most visually spectacular techniques, and certainly one of those with the greatest impact on a cocktail’s final flavour. Its concept is elegant in its simplicity: it involves infusing fats into a spirit to capture flavours that would otherwise be impossible to extract.

What it is and how it works

The basic principle is this: fats are soluble in alcohol, but not in water. This means that when you add a fat to a high-proof spirit (vodka, rum, bourbon, gin), that fat partially dissolves, releasing the aromatic and flavour compounds it contains. Then, through a refrigeration process, the fat solidifies and can be separated from the liquid, leaving behind a spirit that has absorbed all of that gustatory complexity.

The result is extraordinary. Think of the flavour of bacon: that deep umami, that smokiness that seems impossible to capture in a transparent liquid. Through fat washing, we can infuse that profile into a bourbon and get an old fashioned with a completely new dimension. Or we can use butter to create a vodka with a subtle creaminess that adds body to the cocktail without adding heavy texture.

Step by step

The technical fat washing process follows these steps:

1. Choosing the spirit: It must be at least 40% alcohol to guarantee proper extraction of fatty compounds. The most common are vodka, white rum and bourbon.

2. Choosing the fat: From crispy bacon to salted butter, desiccated coconut, peanut butter or even truffle oil. Each fat brings its own aromatic profile.

3. Infusion: The fat is added to the spirit in an airtight container. The typical ratio is around 30-50 grams of fat per litre of alcohol. Shake vigorously and leave to rest for 12 to 48 hours, depending on the intensity desired.

4. Freezing: The critical step. Place the container in the freezer for at least 4 hours. The fat will solidify on the surface.

5. Filtering: Using a coffee filter or muslin cloth, separate the clean liquid from the solid mass. The result is a transparent liquid infused with the flavour of the fat.

Types of fat and results

The possibilities are practically limitless. Bacon infused in bourbon creates that smoky, salty profile that has given rise to iconic cocktails. Salted butter adds creaminess and a touch of umami that works extraordinarily well in cocktails with citrus. Desiccated coconut, infused in white rum, transports cocktails to tropical latitudes with an authenticity that syrups could never achieve.

At STILLROOM, we have experimented with more unexpected fats: olive oil in gin for a Martinez with oily depth, hazelnut butter in vodka for dessert cocktails, even crispy bacon infused in rye whisky for a cocktail that redefines the concept of the breakfast cocktail.

If you want to go deeper into this technique and discover how we apply it in our creations, we have an in-depth article dedicated to fat washing in cocktail making that we highly recommend.

Lacto-fermentation: the science of umami flavour in cocktails

If fat washing is eye-catching, lacto-fermentation is almost magical. This technique, used for millennia in food preparation (sauerkraut, kimchi, miso in Japan, yogurt around the world), has found its place in modern cocktail making as one of the most powerful tools for creating gustatory complexity.

The biological process

Lacto-fermentation is a natural metabolic process in which certain bacteria, specifically lactic acid bacteria (LAB), convert the sugars present in a food or drink into lactic acid. This acid is responsible for the characteristic sour, complex flavour of fermented foods, but also for something more subtle and extraordinary: umami.

Umami, that fifth basic taste we perceive as “savoury” or “meaty”, develops naturally during fermentation. As the bacteria work, they not only produce lactic acid, but also break down proteins and other compounds, releasing glutamates that dramatically boost flavour perception.

Ingredients and applications

In cocktail making, lacto-fermentation is applied mainly to fruit, vegetables and other ingredients that contain fermentable sugars. The most popular include:

• Berries: Fermented strawberries, blackberries and raspberries develop a complex acidity that goes far beyond natural citric acid. The result is a fruity yet deep profile, with earthy notes and an acidity that brings life to the cocktail.

• Vegetables: Celery, cucumber or even peppers can be fermented to create syrups and cordials with an extraordinary vegetal complexity.

• Herbs and spices: Fermenting ginger or lemongrass produces aromatic profiles completely different from their fresh versions, with softer, rounder notes.

Typical fermentation lasts between 24 hours and 7 days, depending on the desired result. An oxygen-free environment is needed (bartenders usually use vacuum chambers or vacuum-sealed bags) to prevent the proliferation of unwanted micro-organisms.

Complex acidity

What makes lacto-fermentation special in cocktails is that the acidity generated is not one-dimensional. While lemon or lime contribute pure citric acid, fermentation produces a blend of lactic acid, acetic acid (vinegar) and other organic acids that create a far more interesting sensation on the palate. That complexity is what sets a “good” cocktail apart from one that leaves you speechless.

At STILLROOM, we use lacto-fermentation to create our own bar ferments — such as the Garibaldi Fermentado — and to bring depth to cocktails that would otherwise be too simple. It is a technique that requires patience and attention, but the result completely justifies the effort.

Milk clarification: transparency and elegance

Milk clarification, also known as milk punch, is a technique that seems almost paradoxical: how can milk, an opaque, milky liquid, help create a crystal-clear cocktail? The answer lies in the chemistry of milk proteins and how they behave in the presence of acids.

The traditional milk punch

Milk punch has a long history in cocktail making. As early as the eighteenth century, London bartenders were preparing milk-clarified punches, obtaining drinks of astonishing clarity. The technique fell out of use for much of the twentieth century, but was revived and perfected by modern bartenders such as Dave Arnold and Brad Farran.

The basic process is as follows: milk is added to a cocktail that already contains acids (lemon juice, lime, wine, etc.). Casein, the main protein in milk, reacts with these acids and coagulates, forming small curds that trap solid particles and suspended lipids. When this mixture is filtered, the curds stay in the filter and the liquid that comes out the other side is perfectly transparent.

How casein traps particles

The magic lies in the structure of casein. This protein has an amphipathic nature, meaning it has parts that attract water and parts that repel it. When it finds itself in an acidic environment, casein loses its stability and forms aggregates that act like tiny sponges, capturing any solid particle in the liquid: fruit fragments, pulp, even essential citrus oils.

The result is a cocktail that keeps all its flavour, all its aromatic complexity, but with a visually impeccable texture. It is a glass that looks almost artificial in its clarity, yet bursts with flavour the moment it reaches your lips.

Crystal-clear results and applications

Milk clarification does not just improve presentation; it also softens the cocktail’s rougher edges. Acids that might previously have seemed too sharp become rounder, flavours integrate better, and the mouthfeel becomes silkier without adding any creamy ingredient.

In practice, milk clarification is applied to cocktails that contain cloudy elements: fruit juices, homemade infusions, even certain liqueurs. It is particularly effective in cocktails with citrus, where the juice’s natural cloudiness can look visually unappealing.

At STILLROOM, we have experimented with clarification across a variety of creations. A clarified tea-and-lemon milk punch becomes a drink that looks like mineral water but has the complexity of a fermented tea. Cocktails with exotic fruit that were previously impossible to present elegantly now shine in the glass with a clarity that invites you to drink them before you even taste them.

Homemade cordials: capturing the essence of each ingredient

Homemade cordials represent one of the most versatile and fundamental techniques in advanced cocktail making. Unlike simple syrups, which are little more than water and sugar, cordials are preparations that aim to capture the complete essence of an ingredient, including its aromatic nuances, its natural bitterness and its structure.

The difference with syrups

A simple syrup, whether made from cane sugar or fructose, provides sweetness and perhaps a subtle aroma from the ingredient it is infused with (lavender, mint, rose). But a cordial goes much further.

Cordials are prepared using extraction techniques that seek multiple layers of flavour. Some are made through prolonged maceration, where the ingredient rests in alcohol before the syrup is added. Others use the oleo saccharum method, a traditional technique that extracts the essential oils from citrus using sugar. And others still are shrubs, which combine fruit and sugar with the acidity of vinegar.

Extraction techniques

Extraction is the process of obtaining the flavouring compounds from a solid ingredient (fruit, herb, spice) and transferring them to a liquid that can be used in cocktails. The most common techniques include:

• Maceration: The ingredient rests in alcohol (vodka, rum, brandy) for days or weeks, allowing the alcohol to extract essential oils, pigments and aromatic compounds. It is then filtered and mixed with syrup.

• Hot infusion: Similar to maceration but applying heat to speed up extraction. It requires care so as not to spoil delicate compounds.

• Sous-vide: Sous-vide extraction allows precise temperature control that maximises extraction without damaging the ingredients. It is an increasingly popular technique in high-end bars.

• Oleo saccharum: This traditional technique involves covering citrus peel with sugar and leaving it to rest. The sugar extracts the essential oils from the peel, creating an extraordinarily aromatic syrup that captures the essence of the citrus without needing alcohol.

Oleo saccharum and shrubs

Oleo saccharum is particularly magical with citrus. Orange, grapefruit, lemon and lime reveal dimensions of flavour in oleo saccharum that you will never find in a simple squeeze. Those essential oils from the peel, so difficult to extract any other way, end up captured in the resulting syrup.

Shrubs, for their part, combine fruit and sugar with preservation in vinegar. The result is a cordial that has the acidic complexity of vinegar, but with the sweetness of the fruit and an almost fermented depth. Strawberry or cucumber shrubs have found their place in cocktails that seek that spark of complex acidity.

At STILLROOM, we prepare our own cordials for each season. Every cordial is a unique creation that reflects the ingredient at its peak. And when you taste a cocktail made with a homemade cordial, the difference is immediately noticeable: there is depth, there are layers, there is something you cannot quite define but know is there.

Natural carbonation: bubbles with character

Carbonation is perhaps the most intimidating technique of all, mainly because it involves working with pressure and requires specific equipment. But the results completely justify the investment in knowledge and materials.

Natural fermentation vs CO2

There are two main ways to carbonate a cocktail: by injecting industrial CO2 (the soda siphon method) or through natural fermentation. The first is fast, controlled and produces consistent bubbles. The second is more complex but generates completely different flavour profiles.

Natural carbonation, also known as the bottle fermentation method, uses the yeasts’ own activity to produce carbon dioxide within the liquid. The yeasts consume sugars and generate alcohol and CO2 as by-products. If the process is controlled properly, the CO2 stays trapped in the liquid, creating natural bubbles.

The problem with this method is that it also produces additional alcohol, which can throw off the cocktail’s balance. That is why bartenders usually carbonate using an intermediate technique: adding a small amount of sugar and yeast to an already prepared cocktail, fermenting for a controlled period (generally 24-48 hours), and then stopping fermentation through refrigeration.

Texture and applications

Natural carbonation produces bubbles different from those of industrial CO2. They are smaller, more persistent, and have a creamier texture on the palate. In addition, fermentation contributes its own flavours: notes of bread, yeast, even slightly earthy nuances that enrich the cocktail.

In practice, carbonation is used to create sparkling versions of classic cocktails, to add freshness to drinks that would otherwise be flat, or to create effervescent textures that contrast with the density of spirits.

At STILLROOM, we have experimented with carbonation in cocktails ranging from sparkling versions of the Negroni to floral drinks that look like champagne but have the complexity of a signature cocktail. It is a technique that requires practice, but opens up immense creative possibilities.

Where to try these techniques in Madrid

Now that you know the techniques, you are probably eager to try them. And what better place to do so than STILLROOM, our signature gastro cocktail bar on Calle Moreto 9, in Madrid’s charming Jerónimos neighbourhood.

At STILLROOM, every cocktail on our menu is a showcase of these techniques applied with precision and creativity. Our team of bartenders has mastered fat washing, lacto-fermentation, milk clarification, the preparation of homemade cordials and natural carbonation.