[Javaslinger]

Carbonating Stouts (in bottles)... The struggle is real. 

So we brew a lot of stouts - milk stouts in particular - and they all carbonate VERY slowly and sometimes not enough.  These are NOT huge high alcohol stouts.  Generally around 7%.  Usually I'm going for about 2.0 volumes CO2 and I use a calculator to determine the amount of corn sugar.  I do cold crash so I'm bottling at about 40F which means there is a considerable amount of dissolved CO2 already.  Anyway, they carbonate some - enough to hear the hiss when I pop the cap - and they don't taste completely flat - but there is virtually no head. 

I know high alcohol stouts take quite a bit longer, but these are not high alcohol...  Is it perhaps the lactose that's causing an issue?  Possibly something in the grain bill inhibiting any head formation? 

Any thoughts, advice, suggestions?

[Andy Farke]

What temperature are you letting the bottles sit at after bottling? Do you leave them at 40 degrees, or raise them up to room temperature? If the former, they might just be carbonating super slow because of slow yeast action at lower temps.

[Stevie]

2 volumes isn’t very high. Try an aggressive pour to generate head. If you have head retention issues, something else may be amiss.

[Phil_M]

What temperature are you serving at? 2 volumes is low compared to commercial American beer, but a pretty good choice for a British style like milk stout. If served too cold, it will be noticeably flat. Let a bottle sit out of the fridge for 20-30 minutes and see what happens.

[Javaslinger]

What temperature are you letting the bottles sit at after bottling? Do you leave them at 40 degrees, or raise them up to room temperature? If the former, they might just be carbonating super slow because of slow yeast action at lower temps.

I've got them conditioning at about 70F. 

[Javaslinger]

What temperature are you serving at? 2 volumes is low compared to commercial American beer, but a pretty good choice for a British style like milk stout. If served too cold, it will be noticeably flat. Let a bottle sit out of the fridge for 20-30 minutes and see what happens.

I think this could be part of it.  Even with an aggressive pour there is virtually no head straight out of the fridge.  They do have head at room temp.

[Javaslinger]

It seems the issue may be related to the fact that I'm calculating my priming sugar based on the temp at bottling - right after cold crashing.  Apparently you're supposed to determine it based on their temp at the end of fermentation?  That's a considerable difference in the amount of priming sugar...

[riceral]

It seems the issue may be related to the fact that I'm calculating my priming sugar based on the temp at bottling - right after cold crashing.  Apparently you're supposed to determine it based on their temp at the end of fermentation?  That's a considerable difference in the amount of priming sugar...

This is my understanding and how I do it.

I will ferment my beers in the 55*-68* range (depending on style), then cold crash for clarity. When I bottle I base the priming sugar amount on the maximum temperature during fermentation (55*-68*), not the cold crash temperature (35* or so).

CO2 will degas from the beer with higher temperature. Once out though, CO2 won't re-enter the beer once the temperature is cooled down.

At least, that is my understanding. Please correct me if I am wrong.

[klickitat jim]

I suspect you don't have the residual co2 that you think. You said that you crash to 40 and it sounds like you use that temp in your calculation. You should be using the HIGHEST temp that the beer got to AFTER fermentation was complete. The difference... 5gal 2 vol at 40f calls for about 1.5oz, where 70f calls for about 3oz. I bet that is your problem.

Edit: sorry, I just saw that someone else already answered it