Question about kegging pressures across manifold

[OopsMD]

Hello all,

I am brand new to kegging and had questions about changing pressures on kegs across the manifold. For the sake of an example:

If I have a pilsner carbed and serving at 12psi, but would rather have a stout at around 7, can I carb my pilsner, shut off the manifold to that keg, then lower the psi to 7 and let the stout equilibrate?

1. Will the pilsner lose serving pressure since the valve is shut off at the manifold
2. Will the stout lose carbonation if previously carbed at 12, but served at 7?
3. Do you need a second regulator to keep different kegs at different PSIs?

 

[ChiknNutz]

If you were to pressurize to separate values, the pressure will stay the same in each keg until you release pressure. If you have but one manifold with a single regulator, the pressure will equalize across the entire system. That won't happen instantly, but it will if left alone for a few days. To maintain separate pressures in each keg you need to have a regulator/gauge on each branch, typically called a secondary regulator (since you have one on the CO2 tank). Something like this...

 

[McKnuckle]

There are a couple ways of doing this. It also depends a lot on the sequence of things.

For example, if you have your pilsner at 12 psi already, you can do exactly as you propose. Shut off the manifold to the pils, lower the pressure to 7 psi, and allow the stout to carbonate. If you don't serve the pilsner, it will not lose any headspace pressure and will remain unchanged.

If you do serve the pils, it will lose a little bit of pressure with each pour, as the headspace is partially evacuated, and CO2 comes out of the beer to restore equilibrium with the headspace. The effect is not dramatic over a couple of pours. If you do this a lot, then yes - the beer will start to be perceived as less carbonated. So you can control the impact.

If you want to serve the pils and not have this happen at all, simply turn off the manifold to the stout, raise pressure back to 12 psi, serve the pils, let the headspace fill back up, then restore the setup to its previous state.

You can also put both beers up at the same 12 psi pressure, and stop the stout early, then shut off its manifold. Or don't stop it early, but rather allow it to drop in pressure the way I just described, a little bit each time it is served, until it reaches a point where you like it.

I don't mean to complicate this answer, but I wanted to share that there are several ways to manage beers with one regulator and a manifold where you want different levels of carbonation.

 

[Tom R]

Or maybe just put one of these in our stout gas line:
Duotight In-Line Regulator with Gauge | MoreBeer

Yes, you'd have to change over to Evabarrier lines, but you should do that anyway.

 

[OopsMD]

There are a couple ways of doing this. It also depends a lot on the sequence of things.

For example, if you have your pilsner at 12 psi already, you can do exactly as you propose. Shut off the manifold to the pils, lower the pressure to 7 psi, and allow the stout to carbonate. If you don't serve the pilsner, it will not lose any headspace pressure and will remain unchanged.

If you do serve the pils, it will lose a little bit of pressure with each pour, as the headspace is partially evacuated, and CO2 comes out of the beer to restore equilibrium with the headspace. The effect is not dramatic over a couple of pours. If you do this a lot, then yes - the beer will start to be perceived as less carbonated. So you can control the impact.

If you want to serve the pils and not have this happen at all, simply turn off the manifold to the stout, raise pressure back to 12 psi, serve the pils, let the headspace fill back up, then restore the setup to its previous state.

You can also put both beers up at the same 12 psi pressure, and stop the stout early, then shut off its manifold. Or don't stop it early, but rather allow it to drop in pressure the way I just described, a little bit each time it is served, until it reaches a point where you like it.

I don't mean to complicate this answer, but I wanted to share that there are several ways to manage beers with one regulator and a manifold where you want different levels of carbonation.

This seems like the best way to do things... Thanks!

 

[OopsMD]

If you were to pressurize to separate values, the pressure will stay the same in each keg until you release pressure. If you have but one manifold with a single regulator, the pressure will equalize across the entire system. That won't happen instantly, but it will if left alone for a few days. To maintain separate pressures in each keg you need to have a regulator/gauge on each branch, typically called a secondary regulator (since you have one on the CO2 tank). Something like this...

View attachment 716297

Yes, i kind of figured. I was looking for a way around buying more regulators (just built the kegerator!) $$$

 

[McKnuckle]

Another trick to serve different beer styles with a single regulator and psi setting is to naturally carbonate in the keg. Yes, it adds 2 weeks to your wait time. Yes, the beer needs that anyway. And it allows you to prime each one pretty much exactly to the carbonation level you prefer.

You can also get into spunding to save time and accomplish the same thing - but that's a little more hit or miss.

Anyway, by carbonating naturally, the beer goes on tap at the right level from the get-go. You can attach your 12 psi (for example) gas source and leave the valve closed until you feel it needs a "goose" of CO2 to bring the level back up. Do that, fill the headspace, and close it off again. You save a ton of CO2 this way because the vast majority of it is coming from the yeast.

Before you buy more stuff, give some of this a try.