During the COVID-19 lockdown, my favorite local roaster had temporarily closed their retail shops, and being unwilling to spend $8 to get a bag of coffee shipped literally across the street, I decided to try to find other local roasters who made decaf that I could buy at the grocery store, with the hopes of finding something espresso-suitable. I failed.
Thankfully, Vivace reopened this week so I am now well-stocked on good coffee. But I still have a bunch of other coffee hanging around, so I decided, why not try making other things with it?
The first experiment: making cold-brew coffee soda.
Coffee used: Zoka Tangletown. This is a medium-roast coffee which had some nice complex flavors, but wasn’t quite right for espresso. It made for some pretty good Aeropress, though.
To that end, I did a fairly coarse grind (#20 on my Baratza Encore) of 75 grams of coffee, and immersed it in 600mL of water in my Hario Mizudashi pitcher (affiliate link). I tried a small cup of it and found the Zoka to be unpalatable for coldbrew as well, but instead of throwing it out I allowed it to brew for well over a week in the refrigerator (which probably made no difference).
Anyway. I had about 500mL of coffee left, so I combined it 1:1 with cold water and direct-carbonated it in my Sodastream, then added 12 sugar cubes for a total of 4 tablespoons of sugar. I let this sit to dissolve for a while, and then gave it a taste, and decided to add a teaspoon of lemon juice which gave it a much brighter flavor.
A note on the above technique: The Sodastream isn’t intended for direct carbonation; you’re meant to only carbonate water, and then add concentrated flavorings to it, with good reason – stuff in the water makes for perfect nucleation points, which makes for a big mess when you add carbonation. However, if you’re careful about carbonating things and allow it to decompress very slowly you can often make it work out. In my experience it works best if you avoid direct-carbonating things with sugar in it. I’ve also had good results using a soda siphon but that makes it much more difficult to adjust the flavor after-the-fact.
Similarly, the reason I used sugar cubes instead of granulated sugar is that granulated sugar provies many, many more nucleation points, and will likely cause the soda to fizz rapidly and make a big mess. Even with sugar cubes you need to be careful and slow, and it’s a good idea to be ready to cap the bottle and wait for a bit (as I did every few cubes). Simple syrup or another liquid sweetener is another approach you can take; when I make lemon soda I usually use agave nectar, for example, although it also introduces other flavors that I didn’t think would work well with coffee.
Anyway! This soda came out pretty good. It’s crisp and refreshing without being too cloying, and tastes, well, like coffee. Back when I lived in NYC I became somewhat fond of Manhattan Special, although I found it too thick and syrupy. This soda tastes like how I remember Manhattan Special tasting, but less sweet and without the syrupiness.
I am out of Zoka at this point, but I have a ridiculous amount of Whidbey Coffee, whose decaf is a very dark roast and definitely not to my taste (even via drip or Aeropress). But maybe I can figure out something else to do with it. Its flavor really wants to be paired with dairy, so I suspect I’ll be making ice cream next.
Also, for a more principled and scientific take on how to build a coffee soda, it’s worth looking at James Hoffmann’s recipe.