Foam/krausen but no bubbles in air lock

General Homebrew Discussion
1

I brewed two batches of a Duvel clone, a recipe from the cloud site. A blond ale with 7-8 % alcohol.
One had 1077 as OG, the other 1079.
I used Safale 256 on the first brew, and warmed it up to 23 degrees.
I used Mangrove Jack M31 on the second batch and warmed to 23 degrees too.
The first batch started and is happily bubbling away.
The second is not producing any gas/bubbles. I opened the jar and saw a lot of krausen.
That was approx 26 hours ago. The krausen has diminished a lot, but the wort still does not produce any gas.
I checked the cover and airlock, even replaced them. Still no bubbling.

How is it possible that there is krausen and no gas is produced ?
Both worts are fermenting in a conical Fastferment jar.

2

Gas is being produced. It is just getting out some other way. You either have a leak in the seal of your vessel or the lid wasn’t installed just right.

3

To force the CO2 produced by fermentation out the airlock, put a little keg seal lube on the fermenter lid so it seals well to the fermenter.