At GrowlerWerks, innovation is in our blood. And not surprisingly, many of our customers also like to experiment and push the limits of what they can do with their uKeg. Consequently, we get a lot of questions about our CO2 and Nitro gas cartridges, and if they can be used interchangeably in our carbonated and nitro uKegs. The answer, however, is not cut and dry. So, we thought we'd put together a little primer on the different gas cartridges and how they can (or cannot) be used in our products.
Understanding the different types of gas
The two types of gas used in GrowlerWerks products have distinct characteristics. CO2 gas creates or preserves the small bubbles in carbonated beverages like beer or club soda. Nitro gas creates much smaller bubbles, which give beverages like nitro cold brew a silky-smooth texture. In addition to infusing the beverage with gas, both gases are used in the pressurization system that dispenses the liquid from the bottom of the vessel, through the internal tube, and out the tap.
Important to note, each gas has its own flavor, which is imparted into any liquid it infuses. CO2 has an acidic taste, whereas Nitro has a slightly sweet taste. This is important to remember when experimenting with gas.
Can I use a CO2 cartridge in a uKeg Nitro?
In a word, no. The uKeg Nitro uses a specially designed nitro tap that turbulates as it dispenses. This process is what creates the cascading pour associated with nitro cold brew. The uKeg Nitro was also designed for higher pressures. Putting a carbonated beverage in the uKeg Nitro and using a CO2 cartridge will cause it to pour extremely foamy from the nitro tap.
Can I use a nitro cartridge in a uKeg PRO or GO?
Yes! Using a nitro cartridge in a uKeg PRO or GO is a great option for serving non-carbonated cocktails such as Manhattans or Old Fashioned's that don't need CO2 to preserve their carbonation levels. The taste imparted by nitro gas is also more subtle and likely more palatable for certain cocktails. Over time, a nitro cartridge will infuse whatever is in the uKeg with those tiny bubbles described earlier and give a creamy texture to the beverage.
If your goal is to use a uKeg PRO or GO for nitro cold brew, there are a few other considerations. The uKeg Nitro was specially designed for cold brew coffee. It has an internal filter to keep any coffee grounds that escape during the brewing process from clogging the tap. So, if you do want to use your PRO or GO for cold brew, it's best to brew it in another container and then transfer the strained or filtered product into your uKeg. The uKeg PRO and GO also don't have the nitro tap. So, while a nitro cartridge will infuse the cold brew and give it a creamy mouthfeel, it won't deliver the cascading pour that you get from the uKeg Nitro.
Can I serve nitro beers in the uKeg Nitro?
Technically you can use a nitro cartridge in the uKeg Nitro and fill it with a nitro beer like Guinness—but it won't create a true nitro experience. Nitro beers are carbonated and served using "beer gas," which is a combination of CO2 and N2. This creates a slightly carbonated, smooth, and silky beer. Using a nitro (N2O) cartridge will approximate the N2 feel but won't be able to maintain the light carbonation. Over time, the nitro beer in your uKeg nitro will go flat.
If you plan to get a nitro beer fill-up and take it over to a friend's house for immediate consumption, it will likely do the trick. It will keep the beer nice and cold, and the nitro tap will create the cascading pour that we all love so much in nitro beers. But the characteristics of the nitro beer created by the original beer gas will diminish the longer the beer remains in the uKeg.
Still wondering about certain gas cartridge use cases? Send a note to email@example.com and we'll be happy to answer your questions.