This has been brought up in several threads, but I wanted to assemble some information into one good starter post, then ask for advice.
I used to think that they dissolved nitrogen into the beer to get those teeny weeny bubbles in a cream ale or guiness style stout. I don't believe that is true though. Nitrogen does not dissolve so easy into liquid like CO2 does. My new understanding is that back in the day, barrels didn't hold pressure very well, so carbonation like we have now wasn't very easy to accomplish. They would use a beer engine or hand pump to pressurize the beer, then push it out through a restrictor plate that was built into the 'stout' faucets (which performs a similar function as the aerator in your sink faucet - it infuses some air from your surroundings into the beer but most importantly it causes your beer to be agitated, releasing whatever CO2 is in it). Well with the invention of gas tanks and whatever came along with that to make bottling nitrogen possible, it got a little easier. Attach the nitrogen to your system at a fairly high pressure, push the beer through the restrictor plate at high velocity causing it to knock around same as the hand pump and release whatever CO2 IS dissolved in the beer. This method essentially takes a fairly flat beer, releases whatever carbonation is in it, so that your tongue tastes it as a fully carbonated awesome creamy tiny bubble creamy beer.
A few notes:
-Nitrogen doesn't liquify until some insanely high pressure, unlike CO2. This means that the nitrogen tanks are rated for much higher pressures than CO2, and are then crammed full of as much nitrogen gas as possible. Your CO2 tank normally has liquid CO2 in it, until you're about to run out, so the pressure gauge doesn't change until there is only gas left in the tank. The nitrogen doesn't go to liquid, so you will see the needle drop constantly as you use since the less gas that is in the tank, the less pressure. The CO2 tanks maintain the same pressure as long as there is liquid CO2.
SO (takes a deep breath), I want to serve a stout and I want it done creamy and awesome. But I don't want to blow a bajillion bucks on a stout faucet, a nitrogen tank, nitrogen gas, more regulators, and i don't want to have to register with the government (nitrogen is a controlled material after 9/11 because it could be used to make bombs or something I guess).
I've read that there is a method where one could use a stout faucet, or build a small 'restrictor plate insert' for a regular faucet if you have the cajones. Then in order to get the same effect, you store your keg at something like 5 psi to get a little bit of co2 dissolved in there (or prime it with a teeny tiny bit of sugar). Then you can serve it through the faucet but before you do, turn the CO2 pressure up really high. When you're done, release the CO2 pressure off the keg and store it again at 5psi. This basically means you would push the beer at high velocity through the faucet with restriction thus knocking out whatever CO2 is in the beer, but as long as you take off that high CO2 pressure when you're done, the beer itself shouldn't carbonate more. If it does get too carbonated, you're going to get a WHOLE bunch of head on your next pour. Poor pour you.
So my questions for HBT:
Does this method work, has anyone tried it? I've only seen postulations about how it works, but it makes sense.
Regardless of this method, what about the faucets one should use to serve the stout? A stout faucet is really expensive. But a stout faucet can't be used for regular beer easily can it? Cream faucets sound like a rip off and a bunch of bunk from what I've read on the forums, but some people claim success while others say you'd be just as well off pulling your tap handle open just a tiny bit. Could either of those methods be used to serve a low carbonated beer under high pressure from co2?
Restrictor plate inserts: Building my own sounds dangerous. I'm pretty sure the faucet will either explode in my wall or I will coat my walls with a nice new shade of stout coloring. Any suggestions on how to get a restrictor plate on the cheap for use in a faucet? Perhaps there is something that could go in the line near the faucet. Ideas???