Iain McPherson explains how this new technique for jacking flavour came about
Interview by Sam Bygrave
Just when you thought you’d mastered fat-washing, had pored over the details of the rotovap, and found your way around ferments, along comes another technique to investigate. Iain McPherson is the owner of some of Edinburgh’s best bars — Panda & Sons, Hoot the Redeemer, and Nauticus — and he has always been happy playing around with flavour and pushing the boundaries.
Here, he explains how he came up with switching, how it works, and what you can do with it.
How did the idea for switching come about?
I was getting increasingly frustrated with both the limitations of the bar industry and myself. I was bored and frustrated that as an industry we’re mostly following kitchen trends so I decided to lock myself away and push some boundaries. I knew I could bring the ideas if I could find the tools to keep up.
I have always been fascinated by sub-zero temperatures; basically my gelato training makes me an over qualified ice-cream lover. I created a creative space to help me think differently and began to dissect the freezing process.
At its simplest, what is switching about?
In its purest form switching is replacing water in spirits with another non-alcoholic liquid (fractional concentration, and in this specific case freeze concentration), that we then switch with another non-alcoholic liquid. This allows you to be creative with flavour and texture, giving the bartender more freedom to be creative and control over the end result.
How do you calculate at what point the water in a bottle of booze freezes?
There are websites (https://shotgundentist.com/blog/usefull-tools/alcohol-percentage-to-freezing-point-calculator/) that tell you the freezing point of alcohol, but I suggest to drop it a few more degrees to keep the temperature consistent, because the freezer isn’t always the best at keeping a consistent temperature. One issue you need to be aware of is that some brands don’t disclose the level of sugar in their products and this can impact freezing point. In order to get around this you will need to keep dropping the temperature until you find the freezing point.
What are the mixing applications of this technique? How has it worked on your menu?
At Panda & Sons we operate a silent menu. Usually you can spot a keen cocktail enthusiast or bartender and the silent menu offers a wider range of switched cocktails for those who want to experience and know more about this technique.
We found that switching is great for adding texture to a spirit. For example, due to the higher ABV when switching out the water, we can implement an element of the technique called “clarified milk punch”. The bonus though is we don’t have to add additional flavours or acids to aid the splitting of the fats. The higher ABV does this really well. I’ve showcased texture before by adding coconut milk to a white rum. Then with our ‘switched’ coconut white rum we have made a coconut daiquiri. We’re using the same building blocks of flavour but in a different way and with added texture, which I believe always aids flavour.
It’s also a great technique for emphasising existing flavours. For example, with a Scotch that had been aged in IPA casks. Here we switch the water with a non alcoholic IPA, and thus called it a ‘Switched Double IPA’. The results were pretty special.
A category we have been most excited about utilising the technique in is tiki drinks. Most tiki drinks are very diluted with juices. By switching we use the juices to replace the water taken out of the respective spirit. Thus creating a shorter and booze-forward tiki drink. A great example of this is the ‘Jungle Bird’ cocktail. We replace the water from the rum with a clarified blend of pineapple and lime juice (you don’t have to clarify, but we prefer the clear appearance it gives to the cocktail). You are left with a boozier version of the cocktail more synonymous with a tropical rum negroni. Again this showcases the same flavours but rejigging it all around with the use of switching.
How much of working this out was trial and error?
100% trial and error. When you create something from scratch there are no rules and that’s the joy of it. It takes time to perfect a technique and there were many experiments to get switching to where it’s at. What is important however is having a detailed and organised trial and error plan and method.
What kind of equipment do bartenders need to get started?
The main piece of equipment required is a specific type of freezer. I suggest swapping the Rotary Evaporator for this. I use one from the Tefcold SEP range (fridgesmart.co.uk/tefcold-sep- range).
It is an investment but it is more cost effective for the business than for example a rotary evaporator, and easier to fix! Switching is a zero-waste technique, as both the alcohol and the water can be reused. The freezer can also be used as a standard freezer when not switching, and has a decent capacity.