Molecular mixology: Layered, spherified, or dehydrated?

Science is rapidly becoming an integral part of the modern mixologist’s handbook, with cocktail making gaining recognition as both an art and a science in recent years. 

Illustration by Keely Van Order

Illustration by Keely Van Order

Apothecaries, flaming cocktails, and absinthe in the 1800s

It is argued that Antoine Peychaud created America’s first ever cocktail, the Sazerac, while experimenting with alcoholic concoctions for his friends in his New Orleans lab in the early 1800’s. He also created Peychaud’s Bitters, now a staple in any good cocktail bar around the world. Peychaud was an apothecary, or a pharmacist. As an apothecary, Peychaud studied herbal and chemically modified ingredients, developing and distributing medical material to doctors and surgeons. As a precursor to the modern sciences of chemistry and pharmacology, it makes sense that the apothecaries were devising alcoholic beverages during the nineteenth-century; back then, people thought alcohol was medicinal. 

In his book Liquid Intelligence: The Art and Science of the Perfect Cocktail, Dave Arnold writes: “People considered booze to be medicine… bitters were patent medicines compounded by apothecaries from a variety of plant materials chosen for supposed medical or digestive benefits.” 

It’s no secret that science has played a part in creating bangin’ drinks since the creation of the cocktail way back when. Making cocktails began as medicinal, made its way through aesthetics, theatre, science and all the way back around again. Cocktail bartenders do not just make delicious drinks; they experiment, they design, they entertain and they work bloody hard. 

Mr Jerry Thomas is a hero to the bartending world. Known as ‘The Professor’, he was an extravagant entertainer with his jewelled barware and theatrical bartending skills.  At his best, The Professor was earning as much money as the President at the time. Respect. Not only did this pioneering mixologist write the first ever drink book published in the US, Bartender’s Guide: How to Mix Drinks, but he also invented the Blue Blazer. To this day, this is one of the most theatrical cocktails a bartender can attempt, with most probably not game enough to try it: it involves lighting whiskey on fire, distributing it from one tin jug to another, and creating a wall of blue flame. Don’t try this one at home, kids. 

Cocktails with a high alcohol content are sometimes lit on fire before serving, in a technique devised by sailors in the 1700s.   Valo/Wikimedia Commons  (CC BY 2.5)

Cocktails with a high alcohol content are sometimes lit on fire before serving, in a technique devised by sailors in the 1700s. Valo/Wikimedia Commons (CC BY 2.5)


We’ve known that alcohol is flammable since sailors in the 1700s tested the percentage of their rum rations by mixing it with gunpowder to see if it burned. If it did, then it was at least 57% alcohol and less that 43% water (100 proof), hence the measurement of alcohol being 'proof'. A similar yet significantly less dangerous practice is a technique called flaming, which is common with cocktails such as cosmopolitans. A piece of orange rind is squeezed over a flame, igniting the oils to create a shorter, safer burst of fire. This imparts new aromas and flavours, enhancing the essence of the cocktail.

In the late 1800s, famous artists like Vincent Van Gogh and Oscar Wilde were keen drinkers of absinthe. The ritual of slowly adding iced water to a glass of absinthe has been around since these famous men dabbled in their drink of choice, and is now known as the louching effect, or more commonly known as ‘the ouzo effect’. This process changes the absinthe from a clear green to cloudy and thick. In general, when two immiscible liquids are mixed (like oil and water), they will emulsify for a very short time before separating. But absinthe, and other anise flavoured spirits like ouzo and sambuca, will stay cloudy for months, due to the relationship between the anethole found in anise and fennel, high proof alcohol, and water.  

Layering in the mid-1900s

Also known as pousse-cafe, layering is a technique used to create colourful shots and pretty cocktails. Perhaps the most famous of these is the B-52 shot, named after the American 70s band and created with triple sec, coffee liqueur and Irish cream liqueur. The ingredients are layered into a shot glass according to their relative densities, meaning that the coffee liqueur (usually Kahlua) is poured first due to its heavier specific gravity. If poured carefully and correctly, the Irish cream (Baileys) and the triple sec will float on top of the coffee layer, creating the triple layered effect. 

The B-52 shot, layered with kahlua, baileys, and triple sec based on the relative densities of each.   Connie Ma/Flickr  (CC BY-SA 2.0)

The B-52 shot, layered with kahlua, baileys, and triple sec based on the relative densities of each. Connie Ma/Flickr (CC BY-SA 2.0)


Early experimentation with the density and viscosity of liquors in order to make fancy-looking shots employed the principles of scientific analysis that is essential to molecular mixology. The Alien Brain Haemorrhage shot is another example of layering, but takes the process one step further to include the chemical reaction of curdling. The shot is made by layering Baileys on top of peach schnapps, then layering a small amount of blue curacao. The curdling occurs with the addition of a few drops of grenadine which seep through to the baileys. The Baileys curdles because grenadine is slightly acidic; when dairy comes into contact with an acidic liquid, the milk proteins are acidified. This drops the pH level to the isoelectric point, and causes these proteins to coagulate. The end result is an extra ghoulish-looking shot! Delicious.

Eggs in the late 1900s

It’s hard to say when eggs in cocktails really took off as a ‘thing’, but bartenders have been using them to make flips and fizzes before prohibition in the US.  The most common use of egg in a cocktail is using just the whites in various classics to add a foamy texture to the drink, a standard  in sours and fizzes. While the egg doesn’t necessarily change the flavour, it does change how it looks and feels. The silky, foamy texture develops when the egg white is shaken into the cocktail. An egg white cocktail must be shaken without ice first (this is called a dry shake), because egg white foams more easily when warm. The dry shake causes the main protein in the white, ovalbumin, to unfold or unravel, and mix air into the liquid of the white. This air is then trapped by the proteins and forms the fluffy foam. 

In recent years, bartenders have found more technologically advanced ways to create foams. The latest tool for modern mixologists is the iSi Whipper. This Austrian innovation hit the scene in the 90s, when Catalan chef Ferran Adrià started using it at his restaurant elBulli, and became a favourite of the forerunners in experimental cuisine.

The iSi Whipper can be pressurised with gas cartridges (either carbon dioxide or nitrous oxide) through a valve at the top, with the pressure released using a trigger valve and nozzle which dispenses foam (usually whipped cream). Bartenders are now using these whippers to create flavoured foams to add to delicious cocktails.

Molecular mixology in the now

Bartenders are getting as serious about their drinks as chefs are about their food. The term ‘molecular gastronomy’ only came about in 1988, and fancy bartenders even more recently have been dubbed ‘mixologists’. Making cocktails has become much more than the trial and error it began with. Bartenders like Dave Arnold are experimenting with everything to do with mixing drinks, from carbonation to acidity levels in different types of apples. Making a cocktail is no longer just about how the drink tastes, but how it smells, looks, feels, and changes. Barkeeps are playing with unusual flavour combinations, textures, aromas and theatrics to create not just a drink but an experience. If only Jerry Thomas and Antoine Peychaud could see us now!

Gel-oh and dehydration

Most of us have been to a party in the past decade where they were given a colourful, slimy, almost-solid alcoholic shot. You know it: the deliciously dangerous jelly shot. Gelification is being used more recently to produce ornate jelly-shots, or cocktail gels. Gelification is the process of changing a liquid into a gel with the help of a gelling agent such as agar agar and gelatin. These are examples of  hydrocolloids, which are microscopic systems that react when dispersed in liquids. Cocktails are being made using these gelling agents just to confuse you. Is it a drink or is it food?

Gelification allows bartenders to turn standard liquid shots into solid, gravity-defying jelly shots.   db0yd13/Flickr  (CC BY-NC-SA 2.0)

Gelification allows bartenders to turn standard liquid shots into solid, gravity-defying jelly shots. db0yd13/Flickr (CC BY-NC-SA 2.0)


Food is, in fact, a frequent component of bartending, with garnishing becoming a large part of great cocktail making in recent years. Particularly in cocktail competitions, some drinks not only include a fabulous garnish but a delicious accoutrement. A great new-school way of highlighting flavours in a garnish or accoutrement is by dehydrating food. This is most easily achieved by using a dehydrator, but can be done with an oven too. Again, this is not a new discovery; we have been dehydrating herbs and fruit for years, but now chefs and bartenders are using this method for increasingly creative endeavours. Dehydrating food can turn something soft and juicy like a strawberry into a crunchy flavour explosion or a subtle powder, adding texture and additional layers of flavour to the cocktail.

Then there are booze balls: gelatinous spheres of a liquid of your choosing. Spherification can occur with foods of a pH higher than 7, and is a chemical reaction between sodium alginate and calcium chloride. When these two chemicals come into contact, they rearrange so the alginate attaches to the calcium, forming the gelatinous calcium alginate.  A fruit juice or soda becomes a jelly-like ball with a liquid centre. So, how would you like your martini? Wet, dry, dirty or spherified? 

Got chemistry?

Everyone likes a bit of theatre at the bar, and the most impressive bar stool theatrics lately involve the smoking cocktail. Scientists… I mean, bartenders, are using liquid nitrogen (LN) to chill your martini glass now - because ice is just too mainstream. Liquefied nitrogen gas is -196ºC and, when not used safely, can cause cold-burns, or worse if ingested. However, when it is used correctly, it causes oohs and ahhs from astounded customers. LN turns into fog when exposed to air, so when a bartender splashes it over a cocktail glass, it looks like a wacky science experiment. Cue the oohs and ahhs. Dave Arnold loves LN, describing it as “mesmerizing, fantastic stuff. It can chill glasses almost instantly. It can chill and freeze herbs, fruits, drinks, and other products without contaminating or diluting them in any way.

But it’s not all smoke and mirrors. There are a few horror stories surrounding the use of LN, such as a young woman in England who lost most of her stomach and almost her life when she ingested it. Needless to say, there are now very firm safety rules that bartenders need to follow when performing these theatrics. 

Dry ice is also used in some cocktail bars for that smoky-effect. Dry ice is the solid state of carbon dioxide, but it is much warmer than LN at -78.5ºC. Dry ice is easier to come by and safer to use - however, it will slightly alter the flavour of the cocktail to become more acidic or more carbonated. 

Perhaps we can leave some of the more complex and dangerous aspects of cocktail making to the actual scientists, then. Or the professional chefs. Take your pick.

In the meantime, someone get me a vodka, soda with fresh lime. Thanks.