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Using the Power of Ice for Infusions | Sous Pression

Hi, Friends of Cocktails. Today I’ll show you another cool and innovative cocktail technique, and when I say cool, I mean we’ll literally be freezing a cocktail to add a new flavor to it. The technique is called Sous Pression and it was created by Iain McPherson. In short, the power of expanding ice will help us to leach out flavors from an ingredient and change the cocktails we’re making - think of it as an alternative to Sous Vide. We’ll also make two cocktails with this technique, first, one of many signature cocktails from McPherson’s bar, Panda&Sons, then we’ll make a Manhattan to see what happens to it, for the fun of it. If you’re ready to learn something new, let’s start

I again came across this technique from a article back in February, titled ”Forget Sous Vide, Sous Pression Is the Key to Better Cocktails”. This time I contacted the bartender directly and he’s the nicest guy ever. A real panda, if you will. On Instagram you’ll find Iain McPherson under @thecocktailpanda handle, and in real life he’s on the move between his lab and a number of his bars. His bio says he’s a “cocktail & Freezing techniques nerd”, but he’s also been called the Willy Wonka of the drinks world.

He even sent us a copy of their new cocktail menu at Panda&Sons. It’s titled Transcend and it’s dedicated to freezing techniques, with the latest one being the Sous Pression - we might try out some of the other techniques carefully developed by Iain and his team in future episodes. The menu has already been nominated for some awards this year and if you’re ever in Edinburgh you should really go check out Panda&Sons. But let’s focus on this latest innovation in the cocktail world.

Assuming you have a freezer for your ice you’ll really need just one more thing. Something that can withstand the pressure of expanding liquid inside it. I’ll be using a small 2 liter keg and my trusted isi cream whipper. On amazon you can get a small 64oz Mini Keg Growler for as low as $25. I’ll leave a link to these in the description. Once we fill these to the brim with the cocktails, we’ll place both in a freezer for long enough to freeze all the way through, so make sure you’re not using something that’s double wall insulated.

The key here is to make sure we know the exact total volume, so that when we add the cocktail, and in this case, sliced grapes for the infusion, we really don’t leave any space for the cocktail to expand when it freezes. That way all that force will go inwards and it will have nowhere to go but inside of our fruit, similar to what would happen with a rapid infusion or in a vacuum chamber. Once it’s completely frozen we’ll take it out of the freezer, let it thaw out and all the components will fuse together, creating a smoother and seamless flavor.

You can use any fresh fruit or herbs to infuse the cocktail, or even infuse only a certain ingredient, just know that you really need to make as much of it as it will fit in the container. Iain also found out that even if you freeze just the cocktail, it will round out the alcohol and change the acidity, resulting in a smoother finish. We’ll test this theory out with our smaller container, but if you want to learn more about Sous Pression and how it came to be, check out the full episode on YouTube for a small interview we had with Iain himself!

It’s really my pleasure to offer this small platform to showcase innovative techniques and influential people that push the mixology community in the right direction. Iain and his team at Panda&Sons are doing that with the right attitude. Now it’s time to start the process of making the Sability cocktail from their Transcend menu using the Sous Pression technique, it’s Cocktail Time!


● 738mL Citadelle Jardin d’ete

● 410mL Lustau Blancao Vermut

● 328mL Fino Sherry

● 41mL Maraschino Liqueur

● 303mL water

● 287g sable grapes

We first have to measure the exact volume of our keg. The easiest way is to place it on a scale and fill it to the top with water. Using grams and milliliters it’s easy to see that my keg has a volume of 2 liters, but I’ll go with 2.1 liters, just to be safe. I’ll then use this number to calculate the total amount of the ingredients I need for the batched Sability to completely fill the keg. I know the single serve ratio is 45 ml gin, 25 ml vermouth, 20 ml sherry, and 2,5 ml maraschino, and each serve gets 17,5 grams of sable grapes. To this I’m also adding 20% of dilution, which is 18,5 ml, to make it possible for our cocktail to freeze.

All of this gives us a total volume of 128 ml, so if we divide the total volume of our keg with the total volume of the cocktail we get the number we’ll multiply each ingredient with - for me that’s 16,4. So add the ingredients into your keg, close the lid and place in the freezer. At Panda&Sons 24 hours is enough, but I’m going with 48 h just to be sure. After this time has passed, we’ll also have to give this enough time to fully thaw out. Until that point this is still under a lot of pressure, so don’t be surprised if the immense force actually expanded the keg slightly.

So leave this to sit for 24 hours, giving it extra time to infuse, that way you can also be completely sure the contents have liquified again, then open and strain out the cocktail, keeping the grapes for the garnish. Something you might notice after a few batches is that the color isn’t always the same, for reasons unknown. It might be the amount of time you leave it to thaw out and infuse, but for now all you need to do is keep your cocktail in the fridge and once it’s chilled, serve it in a chilled coup - since dilution was already added. Finally, some grapes from the keg as the garnish, which are also an amazing boozy snack.

After this long process, I can’t wait to take a sip of this, Cheers! You first get grapes and varietal aromas. It’s really wonderfully smooth and balanced, with a pleasant citrus undertone from the gin. Sable grapes also give it a subtle floral aftertaste, which is just lovely. Well worth the wait, but as mentioned we’ll also try another batch, this time just with the cocktail, to see how the Sous Pression affects the taste and mouthfeel of a classic. And since we already covered nearly 140 years of its history, it’s only fitting to put the Manhattan under a little pressure. Let’s start measuring.

Sous Pressed Manhattan

● 326mL Maker’s Mark Bourbon

● 163mL 9 diDante Inferno vermouth

● 9mL Angostura Aromatic Bitters

● 222mL water

I’m using the specs for the total amount of a chilled and diluted Manhattan from Dave Arnold’s Liquid Intelligence. It shows a total volume of just over 132 mL and an ABV of 24,6% meaning it should freeze at about -15,5°C - that’s 50 proof and 4°F, so we should be good with our freezers at home. I also measured the volume of my cream whipper, 720 ml, and I’ll divide that with the total volume of a single serve. That lets me know I could fit 5.42 Manhattans into this siphon, so we’ll use that number to multiply each of the ingredients.

So mix your ingredients before pouring them into the cream whipper, close it tight, this time without adding a cartridge and place it in the freezer. I’ll leave this Manhattan in the freezer for the same amount of time as the Sability, and once it’s frozen and thawed just pour it straight into a labeled bottle. Put it in the fridge to chill again and get a chilled coupe once you are ready to serve. For a Manhattan I’m of course adding the classic cherry, and if you’re thinking you could add cherries into the sous pression, you’re right - it’s already on the Transcend menu.

Here we want to see what sous pression does just to the cocktail, so let’s give it a try! Cheers! The Sous Pressed Manhattan brings exactly what you’d expect, from the aroma to the palate. All the flavors are wonderfully balanced and maybe slightly rounded, but if you want the full benefit of Sous Pression always add an ingredient that ice can force the most out of. It was a ton of fun for me to try this and I’m always inspired by incredible bartenders trying to push the boundaries of what’s possible.

If you know of any other interesting techniques you’d like to see me try, let me know, and until next week, Friends of Cocktails!


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