I’m experiencing something strange and am wondering if any else might weigh in.
I’ve made 4 variations of an imperial stout (Kentucky Breakfast Stout inspired). Each was big. In 3 of 4 variations, force carbonation was really not working well.
My normal process is to keg, and simultaneously chill and force about 40 psi of CO2. I do this for about 2 days and then release and repressure at about 15 psi. This works for me for any beer I make.
But, these stouts are nearly flat after 2 days at 40 psi and at 34 degrees F.
They are big - OG 1.115, FG 1.030 (but never had a problem with Barleywine).
They contain oatmeal, coffee, 100% cacao (no added oil or fat) and bourbon - but I don’t “think” these matter.
Any idea what might slow gas from reaching equilibrium in the liquid?
(Right now, I’m using the shake method, which is working).
The only times I’ve had a beer that did not carb in the usual amount of time was when I had an imperceptible (no bubbles showing even when using leak detector) leak, always around the keg lid. Opening the lid, wiping the gasket dry, applying a generous application of keg lube always fixes the problem for me.
As I mentioned, I couldn’t see the leaks even using a mixture of dish soap and water. All I can say is that when I removed the lids and recoated the gaskets with keg lube the problem went away.
I have had the same experience when forcecarbing a high gravity wee heavy. My usual process is to set the the vol of CO2 for the carbonation level I want and let it sit for a week. The wee heavy was still almost flat after a week, but after 3 weeks it was fully carbed.
OK, I’m trying to come up with a reason that a high gravity beer would be harder to force carb and I can’t think of anything. Can someone fill me in on the science?
All I can think is maybe it is a lack of perceived carbonation? Maybe the fact that it is a massive beer, with maybe a little less head than you are used to, you might just not notice the carbonation.
I notice the same thing with my higher-gravity beers. It happens to me usually on the BVIP, which comes in around 10% abv and includes bourbon and vanilla beans. I wondered if it had to do with oils from the beans. But I’m seeing the same thing again with a Sahti that came in at 7.2%.
Again, this makes me lean towards the creaminess/full body you get in a big beer being mistaken for lack of carbonation? As far as I know liquid is liquid when it comes to C02 absorbtion
Well, the Sahti has been carbing forever and I’ve even bumped the pressure up a bit above normal (12 psi). I think what’s happening with the Sahti is that I mashed high and had lots of rye, which is giving me a very full body in the beer. Perhaps it is in fact fully-carbed, but I think the full body gives the impression of a restrained carbonation.
I don’t have any science, but I’ve seen the idea in some forum thread or other that oils from things like coffee, cocoa, and oats form an oil slick on the surface that prevents carbonation purely through head pressure.
Since this thread started, I made a 1.115 Barleywine and another 1.115 RIS with oatmeal, coffee and vanilla. The FG of both were within 0.04 pts of each other.
The Barleywine carved in normal time. I have the co2 set for 40 psi at 33 degrees and I had decent carbonation in 48 hours. This is about the same for my more moderate beers.
The RIS was flat in 48 hours and took another couple days to show lower end carbonation.
I’ve tried to find research on viscosity and Henry’s law, but only a few articles have seemed to be related. They are not about carbonation per se, but about more general gas and equilibrium.