Learn what’s going on behind those crystal-clear Margs and Milk Punches. The pros use these techniques all the time – now it’s your turn.
Scan the menu at any of the excellent cocktail bars our country’s blessed with, and you might see something like a Clarified Piña Colada or Milk Punch on offer. These intricate cocktail techniques are very much in vogue right now, and while clarifying cocktails might seem like a tricky, newfangled process – a page straight out of the big book of bartender secrets – they’re not as obscure as they sound. In fact, bartenders and chefs have been doing it for years.
Many trendy places use milk to clarify their cocktails. “Ew, why milk?,” we hear you ask. Well, for lots of reasons, but the biggest is due to the unique proteins in dairy that bind both astringent and bitter agents – polyphenols especially. When the curds are filtered out, so are those molecules. But we’ll get to all that sciencey stuff a bit later. First, let’s have a look at what clarifying actually means, then we’ll get into how you can use this technique at home.
Clarification has been used to make clear stocks and consommés by chefs for yonks. In the bartender world, it was the Milk Punch that first made use of the technique. Some believe it dates back to the 18th century – in Dave Wondrich’s Punch, he points out that in those times, people would often use milk to soften the acidic effect most fruit punches had on the stomach. Back then, it was probably used as a way to make harsh “medicines” that consisted mainly of lemon, sugar, spice and rough-tasting liquor more palatable, giving it a clever look and a rounder, lighter flavour.
These days, clarification in cocktails refers to a range of techniques designed to alter the appearance, texture and flavour of a drink. In layman’s terms, it’s the process of removing suspended (or solid) particles from a liquid, with Milk Punch being the most famous example.
In his book Liquid Intelligence – a total mixology bible – David Arnold outlines three main methods of clarification: filtration (blocking certain particles while letting others through), gelation (trapping particles in gel), and separation by density (using gravity to separate particles out). Some of these are easier than others to replicate yourself – separating by density requires expensive equipment like centrifuges that are more at home in a fancy lab, but filtration is something you can do with relative ease (and patience).
Bartenders love clarification for its ability to create show-stopping crystal-clear versions of well-established cocktails. But different clarification methods are used for different purposes and render different results, from see-through liquid to creating uncharacteristically soft, creamy mouth feels.
Milk is just one ingredient you can use for clarification. By adding a cocktail (or single spirit – more on that shortly) to milk, splitting it into curds and whey using an acid (such as lemon juice), and straining the curds off through a filter (such as a coffee filter, tea towel or cheesecloth), you’re left with a clearer cocktail that’s also rounder and lighter in taste and texture.
We touched on this at the start, but basically, it works because milk contains a protein called casein that binds to suspended particles as it curdles – particularly those associated with bitter and astringent flavours (AKA polyphenols). When you dump the curds, all those particles that have bound to those proteins get shipped out, too. However, there are other proteins that stick around, so be prepared for the cocktail’s texture to also change in the process. Whey proteins stay behind in the filtered liquid, giving the drink a silky-smooth mouthfeel and, when shaken, often produce a fluffy cocktail head.
Take, for example, when you clarify a Piña Colada – a traditionally thick drink that is anything but clear. When you introduce milk to the equation and go through the process of clarification, you’re left with an almost clear cocktail that retains many of the same flavours, but the texture and strength of those flavours have been lightened.
If you’re wondering if you have to use milk, it doesn’t have to be cow’s milk, but it does make the process easier. It also can’t be a milk substitute – skim milk and nut milk won’t work. So, if you want that perfectly round flavour that comes from whey, the easiest thing to do is use cream or full cream milk. Another example of filtration uses egg whites. This is a classic chef’s trick for clarifying stock and works in the same way milk does – coagulation via heat or acidity. Then, by straining off the solids, you’re left with a clear liquid.
Let’s clear one confusing thing up: generally, when bartenders refer to milk-washing, they’re not talking about clarification – even though the technique is essentially the same. The difference here is not in what you’re doing, but why you’re doing it. If you’re using milk for clarification, you’re adding all of your ingredients to the milk – so your spirits, citrus, fruits, sugars – the whole cocktail. You’re stripping not only the spirit of its suspended particles, but also the juices and syrups, altering the entire drink with a very specific effect in mind.
When bartenders talk about milk-washing, they’re doing the same thing, but to only one ingredient – usually the spirit. Instead of the whole shebang being exposed to the lactose, only the spirit and a citric agent are added to the milk. It will go through the same curdling and filtering process, but instead of a clarified cocktail, you’ll have a “washed spirit” – now creamy and rounded thanks to those whey proteins – that can be used in cocktails.
If you just want to clarify, without adding a wheyish mouthfeel – meaning you just want a clear drink – there are some other ways to do it, but be warned, they are fiddly. These methods work well for juicier cocktails, where a milky texture just isn’t going to work.
The first is gelification, using something like agar agar (a jelly substance from algae) or gelatin. The way gelification works is to essentially trap all the solid stuff that makes your drink cloudy and turn it into a gel. The agar agar and gelatin are full of chain-like molecules that unravel when heated. When cooled off, the liquid sets and these molecules interlace again, creating a semi-hard mixture. To retrieve the liquid from the gel, you have to freeze the mixture, and then let it thaw. Once it's thawed, you can then filter out the liquids.
Another way to clarify is to use gravity to separate the solids via a centrifuge (it sounds very sciencey, and it is). A centrifuge applies huge amounts of force (several thousand times the force of gravity) to a liquid or puree forcing it to separate. All the gritty sediment and particles fall to the bottom making a kind of mash. The oils float to the top and what’s left in the middle is your clarified liquid. However, unless you’ve got a bit of dosh lying around to buy a centrifuge (or are lucky enough to have access to one), this isn’t the most accessible method for clarifying your cocktails.
