Infusion

What is an infusion?

An infusion is flavour drawn out over time: you place fruits, spices, herbs, flowers or barks in a liquid, and over time their colour, aroma and taste migrate into it. You know the principle from tea: hot water plus tea leaves gives you, after a few minutes, a drink that neither ingredient could deliver alone. The same thing happens at the bar, mostly with spirits, syrups or mixed drinks as the liquid.

The beautiful part: the aromas soak into the whole drink. They do not sit on top like a garnish, they travel through every single sip.

The technique: how aromas migrate

An infusion is chemistry of the hospitable kind. The liquid works as a solvent, alcohol also dissolves fat-soluble aromas, water above all the water-soluble ones. A few rules determine the result:

• Time: hours to days, depending on the ingredient. Coffee and tea need minutes, roots and barks happily take longer
• Alcohol content: a high alcohol content dissolves bold, oily aromas, such as those of spices, a milder one suits fruit better
• Temperature: heat speeds up extraction but can make fine aromas evaporate, which is why bars often infuse cold
• Quantity: more ingredient means more aroma, but beware of overdoing it

Modern bars accelerate the process in various ways: with a blender, with controlled temperature in a water bath, and even with cream whippers and nitrous oxide, which shorten an infusion from days to minutes. Dave Arnold's "Liquid Intelligence" made such rapid infusions widely known.

Crucial: taste regularly and strain in time, ideally fine with a double strainer. An over-extracted infusion tastes bitter and harsh, especially citrus pith and cinnamon get loud quickly.

The taste: depth instead of decoration

What does an infusion deliver in terms of taste? The difference to a garnish is the core: a rosemary sprig on a drink only smells when you bring your nose to it, a rosemary infusion runs through every sip. That is why bartenders rely on infusions when a drink is truly supposed to taste of something:

• Integrated instead of placed on top: the aroma is part of the liquid, not a costume on stage
• New layers: cucumber in gin, elderflower in vermouth, chilli in rum, the spirit gains a second character trait
• Signature: every bar builds its own infusions, they are a piece of identity on the menu
• Control: through time and quantity you decide how loud the aroma becomes

From emperor legends to monastery liqueurs: a short history

The world's oldest infusion probably sits in your kitchen: tea. China's tea culture is thousands of years old, and legend attributes the discovery to Emperor Shen Nung, into whose pot of boiling water leaves are said to have fallen. As a story it is charming, as evidence it does not count.

In Europe, infusions were cultivated above all by monasteries: for centuries monks have steeped herbs, roots and flowers in alcohol, and some of the world's most famous liqueurs come from that tradition. The best-known example is Chartreuse from the Carthusian monks, whose complete recipe, according to tradition, only two monks know at any given time. An infusion as a state secret that has worked for generations.

Distinction: infusion as the umbrella term

Here it gets elegant, because several terms from our glossary are infusions at heart:

• Fat washing: an infusion in which fat is the aroma carrier, for example bacon in bourbon
• Oleo saccharum: the oils of the citrus peel migrate into the sugar, related to an infusion, only with sugar as the partner
• Shrub and cordial: fruits steep in sugar and vinegar or in sugar water
• Super juice: the peels rest in an acid solution and release their aromas

Remember: infusion is the roof, fat washing and oleo saccharum are rooms beneath it.

At our lounge

If the flavour of cucumber, rosemary or berries carries all the way through one of our drinks, a homemade infusion is most likely behind it. Feel free to ask our team what is steeping right now, infusions are the most honest way to turn a drink into something of its own.