Kegging my first batch, PSI concerns...

[ChefSpam]

So I've brewed a batch of a Bavarian Hefe, and now its time to carbonate. After doing plenty of reading on proper CO2 Volume ratio's, Blast carbing vs slow force carbing, tube lengths for output balancing, etc... I still have one or two questions.

Once a beer is carbonated at the proper PSI, do I have to keep the keg under the same pressure, or can I reduce pressure to a normal serving PSI?

I used to following two charts to determine that my brew is going to need between 20 - 28 PSI @ 38degrees Fahrenheit
Slow Force Carbonation Chart
PSI vs Beer line length balance equation
I've checked and double checked vs other websites, Beer Smith Software, etc...

My second question is, what would be the harm in under carbing a beer? I know flat beer is highly undesirable, but I'm thinking 2.5vol instead of 3.3+. (yes, its under par, but certainly not flat) Until I did this research, I never knew that wheat beers needed so much more than most other varieties! I'm willing to bet that 95% of the bars in my area don't know it either, and have been serving it at 10-12PSI like every other commercial brew they have on tap.

 

[Hammy71]

I usually serve and carb my wheat beers around 18 psi @ 38 degrees. But be warned. Wheat beers usually foam a lot, especially at that high of a pressure. For my wheat beers I use this:

https://www.homebrewtalk.com/f35/cure-your-short-hose-troubles-100151/

Allows me to serve at a high psi and still get beer in my glass, not just foam.

 

[erikpete18]

You can lower your psi to serve, but you'll have to raise it back up after you're done serving or your beer will eventually reduce carbonation. That always seemed like too much of a PITA to me, so I just carb all my beers at about 12 psi (about 40 degrees=2.5 volumes). I've only got two taps, so I didn't want to bother setting up a separate regulator/lines for higher carbed styles. I've done several wheat beers and haven't had a problem with the lower carbonation. Don't get me wrong, once I get a bigger setup I plan to dedicate a tap or two to higher carb styles, but at the moment I don't see a big reason to do so if you are also so inclined.