Am I getting a better seal with my new Fermonster?

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Beer. Because you can’t drink bacon.
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Feb 27, 2020
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Hi folks,
Long time reader, and I've been posting for about a year. I'm in the middle of a secondary fermentation (quite a big Porter) using the Fermonster, and an S-style airlock. Krausen was complete, and I transferred after 5 days.
( I've brewed 12 home batches, but have always used a glass carboy for a secondary and the 3-piece style of airlock. )

There was hardly any action in the airlock for the first 4 days, but now 8 days into the secondary, the airlock is bubbling away quite happily, with fairly big 'burps' every 15-20 seconds. I've never had such vigorous bubbling so late into the secondary, it would usually bubble right away and then taper off near 7-10 days...hmm.

SO! Did I just have a crummy seal using the glass/3-piece carboy setup? It's nice to see that there is still some fermentation going on, but I wonder why I'm getting so much more action later on? Maybe the S-style airlock is more sensitive? The Fermonster does have an O-ring in the lid and a rubber bung that is much more stout than the glass carboy, so maybe I wasn't detecting all the off-gassing in the 3-piece using the glass setup?

Anyhow, very happy with the new addition to my home-brewing kit. Thanks for reading this novel 😁. Hopefully there are some people out there in brewing land that have had the same questions.

Cheers! :mug:
I would guess that your carboys aren't sealing as well as the fermonster does and that is why you are seeing more activity. The other option is an infection, so I'm hoping for the seal being the cause :)
A glass carboy with a well fitting rubber bung and airlock in it is about as tight as a seal you can get. Maybe the bung worked loose?

More importantly, what was the OG?
Which yeast did you pitch, and how much?
Did you oxygenate/aerate when pitching?
What temps were you fermenting at? What ambient temp is it at now?

5 days of "primary" is much too short for completion of big beers, so I'm guessing fermentation wasn't even nearly done when you transferred to the "secondary." Did you get a gravity reading at the time of transferring?

How much headspace is in your current fermenter (Fermonster)? It's probably huge!

Don't open it, the headspace is currently filled with (good) CO2. You want to keep it that way. Exposure to air (oxygen) by opening it is only going to cause problems.
Leave the beer be!
Just let it go until ready to package, maybe a month from now.
OK! Meant to get back earlier, but I was busy monitoring another boil, heh heh. ;)

The OG was 1.089 - ish, I pitched one sac of liquid Imperial Loki kveik and I pitched quite high ( 31ºC/ 86 F ). I aerated the wort thoroughly and used a heat belt after closing the lid. I'm also using a little bit of Fermaid-K due to the amount of fermentables. The room where I ferment is around 19ºC/ 66 F, so I wanted to try the heat belt out. ( I've done a fair amount of research with the Loki/Voss strain and pitching at 31ºC is at the 'low' end of this mighty yeast. Some of the farm-style brewers in Norway are pitching upwards of 42ºC! ) Not using the heat belt on the secondary.

I always transfer my wort after 5 days because I'm not using a brew bucket with an airlock, just a regular ole' bucket with a lid from my LHBS. I was also having problems with fruit flies. There was about 10cm/ 4" of krausen and it completely fell after 4-5 days. The gravity after I transferred was dead-on 1.030. The headspace in the Fermonster is about 18cm/ 8" because I bought the 7gal version.

Also, I was using the special 'hop sack' that fits in the Fermonster opening, with 1oz of Magnum and 50g of cacao nibs. I removed this tonight, covered the opening, took a very quick sample and it was 1.028 -ish. FG is estimated at 1.026. Took about 20mins to get back to bubbling, and it's percolating at regular intervals now, instead of the big burps. Maybe the hop sack was holding the gases.
BTW, sample tastes amazing!! 😁 No off flavours/smells and there were no strange floaties in the wort, so I don't think it's an infection, hopefully. ;)

At any rate, I inspected the bung I was using with the glass carboy, and there were really small cracks in the liquid side, so maybe I was getting some leaking. It's obviously still going (woo!) so I won't be opening it again until everything slows down. This is my first 'big beer' using the Fermonster and heating belt as well, so I'm learning new things! Another novel, I know, and I really appreciate the replies. 👍🍻
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It is my understanding that, if the airlock bubbles, you know that the seal is good.

The bubbles can be produced by the fermentation, or by a raise in the temperature of the room which makes the beer release some CO2 even though the fermentation has ended.
The OG was 1.089 - ish, [...]
That's pretty high gravity. I'm not familiar with using Kveik yeasts myself, but read about them, and what I've tasted from others was very good, usually.

Why the secondary, what is it going to do for your beer? Anything that keeping it in one fermenter all the time (e.g., your Fermonster) can't do?

Kveiks like it hot without turning beer into rocket fuel, so good call on the heat belt. Any temp control on it? Do you have it wrapped with some sort of insulation to keep the heat in? You still need to prevent sudden temp drops such as overnight etc. Especially with higher gravity beers, if they stall they's almost impossible to bring back to life.
Why the secondary, what is it going to do for your beer? Anything that keeping it in one fermenter all the time (e.g., your Fermonster) can't do?

I guess it was the way I'd learned, so I just kept going with the primary/secondary setup. Besides, I'd already pitched into my regular bucket before I'd bought the Fermonster - just weird timing. Also, cleaning out those narrow-necked glass carboys was already a pain even after some of the yeast dropped in the primary. I couldn't imagine having a full drop in there! Until I'm able to drill out the recess near the bottom of this new fermenter for a spigot, and get a proper stand or desk for it, I'll probably continue with my current setup.

There isn't a heat control on the Brewbelt, but I was able to keep it plugged in all night, and had the fermenter wrapped up like a 1970's sleeping bag! It raises the temp by about 10 F, and then holds there. Checked the Fermonster tonight, and there are still bubbles, but quite a bit slower. :)