Stout Carbonation level

[Bobb25]

After ten days in the keg at 12 PSI and 40 deg. F.; the carbonation level of my chocolate milk stout is minimal, and whatever head there is at pour disappears quickly. Otherwise the taste is good. Any ideas to improve the situation ?

 

[alane1]

might still be undercarbed. you could try cranking the pressure up to 20-25 and pour straight into the glass, raising the turbidity of the pour. this would dislodge alot of c02 and create a little of that Guinness cascade. If you get better head stability/retention you know it's not recipe related and just undercarbed. If it works just return the pressure back to normal and wait.

Did you use any flaked barley or any other grain for head retention?

 

[day_trippr]

I've found that for my "normal FG" brews (ie: 1.010-1.012 or so) it takes ~2.5 weeks using the so-called "set and forget" carbonation method for a 5g corney to reach equilibrium. The green line is an accurate reflection of what I've alway seen.

But my stouts - with FGs in the 1.020-1.025 range - take at least another week to two weeks to reach the same carbonation level.

There's likely some fluid dynamics explanation for it that I wouldn't understand but it's consistent.

On the up side, last year I switched to a stout faucet and 25% CO2 beer gas at 35 psi and don't really bother to carb the stouts anymore.
There's almost a volume of CO2 left from fermentation, and the beer gas will bring that up to around 1.2 volumes eventually...

Cheers!

 

[daksin]

One other thing that can affect keg carbing is headspace- if you have your keg pretty much completely full (especially if beer is touching the gas tube) the reduced headspace will slow the carbonation significantly.

 

[Zepth]

That carbing chart... Yes, useful info for the scenario. But there is another way. After it's fully chilled use the shake method with regulator set at final "set and forget" pressure. Sure the beer won't accept the CO2 as quickly as if a higher PSI was used, but it isn't really possible to overcarb either. Personally I'm usually just patient enough and wait for it, and it gives anything that made it through the transfer time to settle.

As far as head retention goes, it's possible the chocolate killed it. My first attempt at chocolate stout had the same headless fate.

 

[doug293cz]

One other thing that can affect keg carbing is headspace- if you have your keg pretty much completely full (especially if beer is touching the gas tube) the reduced headspace will slow the carbonation significantly.

Headspace won't affect carbonation rate under normal circumstances. If the keg is full enough that the beer level is above the straight part of the keg walls, then the surface area of the beer is reduced, and the carbonation rate will go down. What does affect the carb rate is the surface area to beer volume ratio. The higher this ratio (the lower the beer volume), the higher the carbonation rate (since the surface area is constant.) At the same temperature and pressure, a 3 gal keg with 2 gal of beer will carb in the same amount of time as a 5 gal keg with 2 gal of beer.

Brew on

 

[daksin]

What does affect the carb rate is the surface area to beer volume ratio.

Technically correct- the best kind of correct! In this world, we're mostly using the same geometry kegs, and it's just more expedient to talk about headspace when describing a 5g batch in a 5g keg. Good point, though.