Nitrogenation, the process of adding finely textured air and CO2 bubbles to beverages under high pressure, has long been a favorite of sweet stout and cream ale drinkers. Traditionally employed when pouring Irish and English ales and stouts, the technique dates back to the mid-20th century. Without a doubt the practice gives beer a smooth, sweet flavor that's rich, less bitter, and lingers pleasantly on the palate. Now baristas have begun to harness nitrogen's powers too since it lends cold-brewed coffee a similarly delicious taste and thickness.
The equipment you need to nitrogenate liquid, first popularized by the legendary Guinness brewery, entails cumbersome kegs, hoses, pipes, and taps. Enter the NitroBrew, a $500 system (the site says to contact the company for international pricing and shipping, but that is roughly equivalent to £325 or AU$ 670) whose creators promise will let any consumer add a nitrogen-powered kick to any drink. While the NitroBrew converts beers and coffee into wonderfully frothy confections, it's a pain to use, expensive, doesn't always work and more often than not dulls the taste of drinks you make.
A sweet but complex pour
The urge to enjoy drinks laden with creamy nitrogen bubbles is a powerful one. Beverages prepared in this manner are seductively smooth, rich and possess a deeply complex yet sweetly rounded flavor. Frankly if done right it's an irresistible combination. Once the sole domain of a handful of exclusive (often imported) stout beers and ales, the allure of nitrogen is now spreading to the coffee world, too.
No matter how much you relish a nitro-poured confection, it's hard to overcome the fact that restaurant-grade nitrogen tap systems require lots of equipment and know-how to install and operate. These setups typically consist of a bulky 5-gallon gas cylinder (with nitrogen and CO2 mix under high pressure), a nitrogen regulator valve, not to mention a specially designed stout tap and a nest of tubing.
The NitroBrew hopes to solve this dilemma by shrinking everything you need to serve nitrogen-infused drinks at home down into something that'll fit onto your kitchen countertop.
Nitro on micro
The NitroBrew may be small enough to shoehorn onto your average home bar but remains a contraption in every sense of the word. Cobbled together from a mix of off-the-shelf parts and custom tools, the kit feels more prototype than prime-time consumer product. The most intimidating component of the NitroBrew kit is its air compressor. Shaped like some kind of internal combustion engine, the hefty (6 pounds, 14 ounces or about 3.12kg) device wouldn't be out of place on top of car hoods or maybe sprouting from a lawn mower.
If you've ever done any hobby airbrushing, though, you might recognize this gadget for what it is, a repurposed Central Pneumatic air compressor model 93657 (also sold under the Harbor Freight brand).The 1/6-horsepower compressor plugs into standard North American three-prong AC electrical outlets and is designed to power airbrush paint applicators preferred by model builders and novelty illustrators.
Connected to the compressor via a coiled hose is a rectangular hunk of metal about the size of a jewelry box. Called a Charging Station, on one side of this box sits a spring-loaded circular hole which actually is a pneumatic switch valve. The valve pushes pressurized air from the compressor into the NitroBrew kettle, "charging" it if you will.
The kettle, the final piece of the NitroBrew puzzle, is crafted from stainless steel and looks like a cross between a tiny pressure cooker and an oversize cocktail shaker. It's within this vessel that the magic of nitrogenation happens. The container consists of a metal lid (sealed by a rubberized gasket) which swivels onto a lower portion designed to hold a maximum of 12 fluid ounces, The lid also houses a pen-shaped nozzle tooled to interface with the Charging Station's switch valve.
It's not easy to NitroBrew
The creators of NitroBrew may claim the device is a breeze to operate, saying, "it's fast to set up and easy to use." In my experience using the system was anything but simple. For starters, the included instructions fall short of what I call a proper manual. Really a five-page computer print-out, the basic document is light on many details, particularly how to operate the bundled air compressor.
Operating the compressor is one of the most confusing aspects of the NitroBrew kit. Not only is it crucial to set the machine's pressure output correctly to achieve quality drinks, the compressor arrived with its controls wildly off the mark.
In the NitroBrew's defense, an additional "quick instruction" leaflet (one page) does say to "adjust the pressure regulator to 35 PSI" but neglects to explain precisely how to do this. I learned (only through a lot of fiddling and trial and error) that I needed to unlock then twist the compressor's regulator knob fully closed first. This is done by spinning the knob counterclockwise all the way even though it feels like doing so will cause the control to pop right off the compressor.
From here I was able to calibrate the pressure setting, confirmed by an analog dial, by switching the compressor on and gradually cranking the regulator knob clockwise. Regardless this procedure is painstaking and far from user friendly. That said, once set properly the compressor will automatically shut off when the internal pressure of the kettle lands on your selected value.