Agar clarification in cocktail making: crystal-clear juices and cocktails

Clarification with agar is a cutting-edge cocktail technique that allows us to obtain absolutely crystal-clear juices and cocktails without losing a scrap of flavour. At STILLROOM, we use agar-agar — a 100% vegetable gelling agent extracted from red algae — at a ratio of 0.2% of the liquid’s weight: first we gel it, then we break the gel with a whisk and finally we filter it through muslin, achieving a transparency similar to consommé while preserving intact the aromatic intensity of ingredients as fragile as lime or pineapple.

How it works: gel, break and filter

Agar-agar dissolved in hot liquid forms a three-dimensional network of microscopic fibres which, on cooling, traps within it all the suspended particles, the denatured proteins and the leftover pulp that cloud a juice or a cocktail. This ability to encapsulate cloudiness is the heart of clarification with agar. Unlike animal gelatine, agar sets at room temperature — below 35-40°C — and needs no extreme cold, which makes it a far more practical tool for working at the bar.

When we mechanically break the gel — by whisking it or passing it through a coarse sieve — we destroy that network, but the impurities remain trapped in the fragments of gel. When we pour everything over muslin or a fine cloth filter, the liquid falls by gravity, clean and bright, while the solid remains stay in the cloth. We apply no pressure; it is the slow flow that guarantees an ultra-transparent result. It is an almost magical process, but on a purely physical basis.

Step-by-step process

The methodology is meticulous but straightforward provided you respect weights, temperatures and timings. At our bar, every step is timed and weighed to the gram. Here we break down the complete process for clarifying any juice or cocktail with agar-agar.

Step	What to do	Detail / temperature
1. Calculate and weigh	Weigh the liquid to be clarified and add 0.2% of powdered agar-agar (2 g per litre).	Precision scale for the agar; the juice or cocktail must be cold before starting.
2. Hydrate and dissolve	Separate 10-15% of the cold liquid, add the agar and whisk to disperse it. Bring that portion to the boil while stirring continuously.	Heat to 90-95°C and keep a gentle simmer for exactly 5 minutes, until every lump disappears.
3. Mix in the rest	Pour the hot mixture over the remaining cold liquid in a large container, stirring for 30 seconds to homogenise.	The thermal shock accelerates the dispersion of the agar but the mixture must not drop below 35°C until it sets.
4. Gel	Leave it to rest at room temperature (or in an ice bath if you are in a hurry) until it solidifies completely.	The gel will be firm to the touch in about 20-40 minutes depending on volume and room temperature.
5. Break and filter	Crumble the gel with a whisk or a fork. Pour the fragments over a muslin or a cloth filter placed over a fine sieve. Let the liquid drip on its own, without pressing.	Complete filtration can take 2-4 hours; the result will be a crystal-clear liquid with the same original aromatic profile.

Agar vs. milk and gelatine

Each clarification method has its own personality. Milk clarification lends a velvety texture and a subtle dairy character; gelatine is a cocktail classic that requires refrigeration and does not always achieve absolute transparency. Agar-agar holds a privileged place when we are looking for an impeccably translucent liquid, adding no extra aroma and suitable for any guest. This table sums up the key differences:

Criterion	Agar-agar	Milk (milk wash)	Gelatine
Origin	100% vegetable (red algae)	Dairy (casein)	Animal (collagen)
Clarity of result	Extreme, like consommé	Opalescent and silky	High, though it may retain a slight veil
Suitability for delicate juices (lime, pineapple)	Excellent; preserves all the acidity and citrus aromas.	Not advisable: lime curdles milk in an unpredictable way.	Good, though it may need cold to maintain its structure.
Residual flavour	Neutral; it does not alter the cocktail’s profile.	A subtle dairy note; it rounds out the tannins.	It can leave a faint animal undertone if high-quality gelatine is not used.
Difficulty and time	Medium; it depends on the slow filtration (2-4 h).	High; it requires resting and curdling the milk with acids.	Low; quick process but requires refrigeration and unmoulding.

How we use it at STILLROOM

At our bar on Calle Moreto, agar clarification is one of the red carpets we roll out for the most ethereal ingredients. We use it above all with freshly centrifuged juices — lime, pineapple, cucumber — which we want to present as crystal-clear water without losing a single note of their freshness. We then integrate those transparent liquids into cocktails where the aesthetic of the empty glass or the diaphanous coupe is part of the sensory narrative we tell each guest.

The technique is even better understood when it crosses paths with other tools from our laboratory. While milk clarification gives us that silky texture ideal for punches or milk punches, agar allows us to create vegan, ultra-transparent mixtures that we then subject to fat washing to add fatty notes — for example, a crystal-clear daiquiri washed with coconut oil — or combine with the lactic acids from our lacto-fermentation. We even accelerate prior infusions with sous-vide infusions before passing the liquid through the agar process, ensuring that every flavour molecule is extracted in a controlled way. This methodology is part of our catalogue of advanced cocktail techniques, with which we pursue excitement through precision.

Three ideas to get you started

Crystal-clear lime daiquiri

Clarify freshly squeezed lime juice with 0.2% agar. Once filtered, mix 40 ml of the clear juice with 60 ml of white rum, 15 ml of sugar syrup and shake with ice. The result is a completely colourless and bright daiquiri, where the lime’s acidity dances without a trace of cloudiness. It surprises when served in a chilled coupe, almost like spring water with a Caribbean soul.

Deconstructed and transparent piña colada

Centrifuge ripe pineapple pulp and clarify the juice with agar. Add 40 ml of that crystal-clear juice to 50 ml of aged rum infused with coconut (you can use a light fat washing with coconut oil) and a pinch of saline solution. Shake and serve in a martini glass: you have a piña colada that looks like water but tastes like the beach.

“Clear Mary”, a reinvented Bloody Mary

Blend very ripe tomatoes, strain them, add 0.2% agar and clarify. You will get a translucent “tomato water” with a pale golden colour. Combine 60 ml of that liquid with 40 ml of vodka, 15 ml of lemon juice and a dash of Worcestershire sauce. Garnish with a celery stalk and a paper-thin slice of radish: the flavour is 100% Bloody Mary, but its appearance deceives and fascinates.