I recently spent a couple of days in London, having been lucky enough to qualify for the UK final of a competition organised by El Dorado Rum and molecularmixology.co.uk/ at Loungelover in Shoreditch. Last year, El Dorado ran a swizzle contest for UK bartenders. This year, each competitor was asked to present two drinks that were, in some way, "molecular". Through the course of the day, we saw some remarkable things - an El Dorado Bloody Mary mix injected into cherry tomatoes that were still on a tree; candy floss made from rum; edible glasses - every one of the finalists did at least one thing that was completely amazing, covering a massive range of possibilities.

As I started throwing concepts around, I started asking "what makes a molecular drink?" Is it about ingredients? Is it about technique? It's hard to see where the line between "classical" and "molecular" mixology lies; maybe there isn't one.

For my first drink, I wanted to play with people's expectations of a drink they would be fairly familiar with - the mojito. I went back to the same thinking that was behind the Inception; as bartenders, we'll often tell people that using a different technique on similar recipes yields different drinks. It's the difference between a Manhattan and a Bradford, but it's we rarely make a direct comparison between, say, a shaken and a stirred version of a drink.

To start off with, I made a fairly traditional mojito - a smaller serve than is standard, because I wanted to present the overall experience in two parts - using El Dorado 3 year old. I added a dash of Boker's Bitters because I wanted to bring something down from Scotland with me, and while Boker's didn't originate in Scotland, it was reborn in Aberdeen. For the second part, I wanted to retain the flavour profile of the traditional mojito while incorporating some key differences.

Two-Step Mojito (pt. 1)
35ml El Dorado 3yr
15ml lime juice
1 barspoon caster sugar
1 dash Boker's Bitters
Combine all ingredients with crushed ice in a small highball. Top with sparkling/soda water. Garnish with a mint sprig.

The first difference was technique. Rather than building (or swizzling) the ingredients with crushed ice, I decided to stir the second part of the drink. There is, I think, an expectation that stirred drinks operate from a certain family of flavours - sweetness, bitterness, spirit; not so much sour - and I wanted to challenge that expectation. In order to do that, I had to do a little work with the ingredients.

If the point of the second part of the drink was to undermine the expectation of a stirred drink's flavour, I felt it was important that the drink looked as much as possible like a classic stirred drink. This meant that I'd have to find a clear, colourless souring agent, which is something I've thought about in the past. Rather than re-using the slightly-MacGuyvered combination of Limoncello and citric acid, I used some agar-agar to clarify freshly squeezed lime juice.

Clarified Lime Juice
300 grams freshly squeezed lime juice
100 grams water
2 grams agar-agar
Place the water in a pan and bring to the boil. Add the agar-agar and mix well with a whisk for at least two minutes. Remove from heat and immediately add the lime juice. Thoroughly mix everything with an immersion blender, and allow the mixture to being to gel.
Once the mixture begins to solidify, transfer it to a chinois lined with muslin or cheesecloth. Break up the gel with a fork and collect the liquid that is released. Pass the resulting liquid through a coffee filter paper, and reserve for later use.
Clarified lime juice will only have a shelf-life of 24 hours at best.

With that out of the way, I turned to the question of mint. As an ingredient, mint works well in a swizzle because the physical action of mixing the ingredients with crushed ice does a great job of releasing the volatile aromatic oils from the surface of the leaves into the drink. I've used mint leaves in stirred drinks before, but I wasn't convinced that simply adding leaves to the mixing glass as I stirred would impart enough flavour to fit that familiar mojito flavour profile. In the end, I took inspiration from the other drink I'd prepared for the comp, and used an iSi whipper and some Nitrous Oxide to pressure infuse some El Dorado 3yr with the flavour from fresh mint leaves.

Mint-infused Rum
150ml El Dorado 3yr
10 grams mint leaves
Combine ingredients in a whipper can, seal, and charge with Nitrous Oxide. Shake for 60 seconds, and leave to stand for 60 seconds. Unseal the can, venting the gas, and strain. Reserve for later use.
Two-Step Mojito (pt. 2)
35ml mint-infused El Dorado 3yr
20ml clarified lime juice
10ml sugar syrup (2:1)
1 dash Boker's Bitters
Stir all ingredients with ice and strain into a chilled cocktail glass.

The two separate serves made up what I called the Two-Step Mojito: there are two steps to making it, but it also refers to the differences between the serves. The first step from the traditional mojito to the molecular mojito is changing how it's made. The second is modifying the ingredients to fit its new form. They're served together so that they can be compared, a chance to explore the differences and similarities between the two forms.

My decision to use Nitrous Oxide pressure infusion in the Two Step Mojito provided a neat link into my second drink. Once I became aware of the technique (pioneered by Dave Arnold at the French Culinary Institute), I was keen to see how far I could go with it. Inspiration came from the starters menu at Monteiths; we've been offering a gin-cured salmon for a while now. Immediately, I wondered how well salmon-cured gin would work.

I wanted to use smoked salmon as I felt the more delicate flavour would be more approachable than that of a more pungent, uncured fish, and it worked better than I could've imagined. The salmon came through strongly on the nose, but let the citrus and juniper notes of the gin (I used No. 3 Gin, primarily for those flavours) emerge in the mouth before reappearing with a hint of smokiness on the finish.

The other benefit to using the Nitrous Oxide process was that it was practical to do in front of the judges. A lot of molecular mixology necessarily takes place behind closed doors, so I thought it would be a nice point of difference to present an entire drink from start to finish.

Salmon-infused Gin
100ml No. 3 Gin
10 grams smoked salmon
Combine ingredients in a whipper can, seal, and charge with Nitrous Oxide. Shake for 60 seconds, and leave to stand for 60 seconds. Unseal the can, venting the gas, and strain. Reserve for later use.

Once I had the salmon-flavoured gin down, I thought about how to use it. As the basic inspiration had come from a starter, I thought it would be appropriate to make an aperitif. I wanted to keep the recipe as simple as possible so as not to distract from the complicated aspect of the drink - the salmon flavour. I added lemon juice, sugar, and some Martini Rosato, not only because it paired well with both the No. 3 and the salmon, but also because the colour would serve to emphasise the contents of the drink.

Where the second part of the Two-Step Mojito was about undermining the expectation created by its appearance, I felt that this drink's appearance had to reflect its ingredients. I'm already asking people to make a leap of faith with the inclusion of an unexpected flavour; in this case, I didn't want to betray that trust with a trick.

I also included a splash of egg white. Because I wanted to do the infusion during the presentation, I had to compensate for the fat content that the salmon would impart into the gin. If I'd prepped it in advance, then I could have frozen the mixture and separated out the solidified fat but, seeing as that wasn't an option on the bar, that fat content would combine with the egg white to create a rich, yet light texture.

Ex Aqua
45ml salmon-infused No. 3 Gin
15ml Martini Rosato
20ml lemon juice
10ml sugar syrup (2:1)
1 dash egg white
Combine all ingredients in a shaker. Dry-shake to emulsify; add ice and shake; fine-strain into a chilled flute. Garnish with a rolled slice of smoked salmon wrapped in a sliver of spring onion, speared on a cocktail stick.

The choice of a champagne flute was more than aesthetic - the shape of the glass concentrates and holds aromas better than a martini or coupette, so that the guest gets a greater depth of flavour when they go to take a sip. The garnish serves as another clue to the drink's somewhat offbeat flavour. Naming the drink was tough - something like Salmon Gin Sour is frankly a little off-putting. Ex Aqua, in Latin, means "out of water", which seemed to refer to the fish content in a more subtle way.

Even after spending a number of weeks prototyping and prepping these drinks, and seeing what the other finalists brought out, I don't think I can answer the question from the start of this post. What makes a drink molecular? I don't know if I could you, but I know one when I see one.

I had a great time at the comp - thanks to Stef and everyone at Inspirit and El Dorado, Matt from molecularmixology, the judges, the other competitors, and our hosts at Lounge Lover - before getting the biggest shock of the day: I won. That's new.