It's a thing of beauty to watch the bubbles cascade and coalesce in the glass. Take that first sip: cool, but not cold, the sharp roasted flavor is tamed by the velvety mouthfeel. People joke that it's not just for breakfast, but you probably wouldn't mind starting out every day with a thick, rich glassfull.
It's easy to see why nitro cold-brewed coffee is so popular: just like with deep roasty stouts, nitrogen reduces the bitterness and acidity, letting other flavors shine. The downside is the premium you'll pay at your local artisanal coffee shop or nearest Starbucks.
Fortunately, you don't necessarily have to drop a five-spot every time you want to enjoy a glass; you don't even need to leave your house. If you already have a normal CO2 keg setup, you can level up by adding nitrogen to the mix. That one-time cost will let you satisfy your cold brew craving and still be able to put your Guinness clone on tap once in a while, too.
Starting from scratch, the cost can be hard to justify, and if you're not already familiar with draught setups, it may be better to look into the smaller scale nitro coffee systems out there. But if you already have a system, including a converted fridge or kegerator, the investment is fairly reasonable:
● Nitrogen gas cylinder, ideally charged with "beer gas," a blend of 75% nitrogen and 25% CO2,
● Nitrogen regulator, which handles the higher pressures encountered
● Special stout faucet, designed to serve beers on nitrogen
You may also want to consider picking up a smaller 2.5 or 3 gallon keg, depending on how quickly you'll go through it. Following good sanitation practices, the coffee should easily keep for at least a couple of weeks. If your household can drink five gallons in that time frame, that's great, otherwise a smaller keg is more efficient.
Cold Brewing Process
There are plenty of recipes out there for cold-brewed coffee. Choose your favorite or follow the one included here:
1. Place 1.5 # (680 g) good quality coffee, coarse ground into a muslin or nylon grain bag
2. Add 2.5 - 3.0 quarts (2.4-2.8 l) filtered water
3. Refrigerate for 12-24 hours. This will yield a rich coffee concentrate
4. Transfer the concentrate to a sanitized keg, running the liquid through a coffee filter to catch any grounds that escaped the steeping bag
5. Top up the keg with 7.5 - 8.0 quarts (7.1 - 7.6 liter) filtered water. You want a total of about 2.5 - 3.0 gallons of coffee
6. Put the keg under pressure with beer gas at about 40psi for 24 hours
7. Drop the serving pressure to 30psi and dispense through a stout tap.
A Few Tips
Remember that qualify in equals quality out. Choose the best coffee you can afford.
While cold-brewed coffee isn't as prone to spoilage as beer, good sanitation practices will ensure an extended shelf life.
Finally, some people prefer using straight nitrogen rather than the beer gas mix. Most are concerned about the CO2 adding carbonic acid. On the other hand, a light touch of CO2 assists that pretty foam cascade, and I think having a little in solution helps with mouthfeel.
If you've already got the nitrogen setup, adding cold-brewed coffee to your rotation is nice treat. If you haven't taken that step yet, this is just another good reason to move forward. This falls into homebrewing's key value proposition: investing in some equipment and process will pay dividends of fine quality beverages brewed to your personal tastes.
As a bonus, this upgrade opens up your beer brewing options as well. Stouts are the obvious addition, but you should take advantage of the gear to try some more creative ideas. A cherry vanilla brown ale, for instance? Or perhaps a nitro charged New England IPA? Get creative and share your experience with us.