The humble whisky soda, you don’t need to go too far back in pub history to find a room filled with effervescing tumblers of the stuff. A delightfully simple combination of Scotch and soda water, maybe with a spot of ice and a twist of lemon if you’re feeling fancy, this unassuming drink was once a staple order in taprooms across the UK. In fact even today, spend an evening wondering the streets of Tokyo’s Ginza neighbourhood and you’ll soon find out the whisky soda is as alive and well in the hearts and glasses of many.
So what makes this simple combination work? Let’s start with the bubbles and a quick bit of terminology house keeping. All fizzy water is, is a mixture of water (obviously) and dissolved carbon dioxide (CO2) so what’s with all the different names? Well the differences are subtle but very important, especially when it comes to mixing.
Seltzer water - just plain carbonated water.
Sparkling mineral water - carbonated water with naturally occurring salts and minerals
Soda water - carbonated water with added salts and minerals
Sparkling water is generally contains lower levels of salts and minerals. It’s these salts that give soda water its name (added sodium compounds) and are the reason it works so well when mixed with whisky. Think of it as seasoning the drink, the same way you’d add salt to food.
Now that we’ve sorted the bubbles, we need to take a look at the whisky. The soda water is going to release and enhance a wide variety of flavour compounds, for better or for worse. Lighter compounds will be more perceptible, so short chain esters, aldehydes and phenols will get a boost. Great for fruity and floral notes, but those smokey phenols in peated whisky can become overpowering, especially when factoring in a lower perception of sweetness due to the drink being cold. Choosing the right whisky for your soda can require come investigation - reading the reviews by Whisky Worlds is a good place to start if you're feeling a bit puzzled.
Another important factor is texture. Whiskies with great body hold up really well with soda, and this is usually down to long chain fatty acid esters in the whisky. When these are combined with soda water, you can get a fluffy, creamy texture in the finished drink. So how do I find one of these whiskies? Googling “Single Malt Scotch Whisky with long chain fatty acid esters” probably won’t yield many results. Time for some insider knowledge! Look for bottles that say “non-chill filtered.”
Chill filtering (literally getting the whisky down to 0°C and filtering it) removes compounds that could make a whisky look hazy in cool conditions, like sitting on a supermarket shelf for example. Great if you want your whisky looking clear, but not so great for our good friends the fatty acids. Bottles with “non chill filtered” will most likely still contain these texture boosting compounds, and should be your go-to for mixing with soda. Bonus tip, any whisky at 46% ABV or more won’t need chill filtering, so almost definitely won’t be. The higher ABV prevents hazing and also helps with flavour intensity when mixed with soda, win win.
Now that we know what we’re doing, allow me to whet your appetite with a few suggested serves:
2 parts Nc’nean Single Malt
4 parts Fever Tree Soda Water
Pour gently into a rocks glass filled with cubed ice. Garnish with fresh mint.
THE FAMOUS ROCK FISH "KAKU-HI"
60ml Suntory Kakubin 43 (from the freezer)
190ml Wilkinson Tansan Soda Water (one full bottle from the fridge)
Pour gently into a small frozen highball glass. Garnish with a twist of lemon
Developed by Maguchi Kazunari, owner of Tokyo bar “Rock Fish”. It’s served iceless, so all the elements need to be kept as cold as possible before pouring (including the custom etched highball glasses he has made for this drink). Most impressively, the brand of whisky used was discontinued 20 years ago, but is now made and sold exclusively to Maguchi for this drink, which is great as he makes an average of 150 of these a day…
COASTAL WHISKY SODA
50ml Nc’nean Single Malt
100ml “Sea Silk” Sparkling Water*
Pour gently into a rocks glass filled with a large ice block. Garnish with fresh samphire.
The “Sea Silk” Sparkling water adds seasoning and texture to the drink with the addition of Sodium Alginate, giving it a luscious mouthfeel and longer finish. Sodium alginate is usually taken from seaweed and is commonly used as a gelling agent in food.
*This is homemade, so you’ll need something to carbonate water.
“Sea Silk” Sparkling Water
500ml Mineral Water
5g Powdered Sodium Alginate
Blend the powder into the water until completely dissolved, then refrigerate for 2 hours. Carbonate to a high level and keep well sealed. Use within a day.