As stated above, nitro coffee used to be made by kegging cold brew coffee and putting it under high pressure (35+ psi) for extended periods of time (2-3+ days). The catch with this process was that not only the time involved, but the coffee also needed to be cold for food safety reasons plus the cooler temps help the nitrogen infusion process.
As people realized that 2-3 days was not an "ideal" situation to make their nitro coffee, since this was after an 18-24 hour steeping process to brew the coffee, they started to look for other solutions as well. That's when agitation came into play. From the start, we always agitated our kegs of nitro coffee - this was a process that we stole from our homebrewing (beer) background as this method was sometimes used to carbonate beer in less than 24 hours vs letting it naturally carbonate over 7-14 days. Obviously a huge improvement in time and it worked for infusing nitrogen into coffee too. Shaking the keg became commonplace for many early shops, cafes and roasteries who served nitro coffee. Some companies who made large amounts of nitro coffee even went as far as rigging up paint shakers to load their kegs in and let the agitation happen automatically.
Obviously, the agitation method wasn't sustainable, and luckily, new products were created to help with nitrogen infusion:
- Quick Cascade Keg Lids
The Quick Cascade Lid was created out of necessity. Realizing that full kegs weighed 40+ pound when full, not everyone had the option to "shake the keg". The Quick Cascade Lid works by introducing nitrogen into the cold brew coffee through a diffusion stone submerged in the coffee rather than directly into the headspace of the keg. This was a huge improvement in nitrogen infustion time, effort and it also created a mroe consistent nitro pour. The main drawback of the Quick Cascade Lid is that it can only be used with corny kegs, not commercial Sanke style kegs.
- NitroNow Nitro Infusers
The Nitro Infuser was built out of necessity to fill a void in the market. The Nitro Infuser allows any beverage to be infused with nitrogen on-demand on its way from the keg to the tap. Additionally, Nitro Infusers are able to be used with sanke kegs in addition to corny kegs.