Help! My fermentation went ballistic then 'stopped'!

[roxburd]

On Saturday I made up a batch of Festival Golden Stag. I put the yeast in a small sterilised bottle with some water and sugar while the wort cooled and it started working nicely. I pitched it in when the wort was at about 26 degrees (yeah, I know, I should have waited a bit longer). The following day, with no external heating, the wort was still at about 26 degrees - I'm using an InkBird temperature controller with the sensor stuck on the outside of the bin with insulation packed over it so it's measuring the temp of the wort, not the room. At the same time, the airlock was bubbling over, full of foam. The foam hadn't covered the lid of the bin but it had filled the airlock and blown all the water out.
So I changed the airlock for a clean one and since then the water in the airlock hasn't moved at all - there seems to be no pressure coming from the fermentation AT ALL.
I was worried that maybe the new airlock had a leak between its stem and the grommet (cheap plastic airlock with nasty seam where the two halves were stuck together in manufacture) so I replaced it with one with a smooth stem... still no movement in the water at all!
I don't think the lid can be leaking - the airlock stem and the lid seal are the only two places the CO2 could possibly get past the airlock U-bend.
I took an SG reading yesterday and it's gone down from 1037 to 1016 so it has done some serious fermentation... and there is a layer of bubbles over the wort. But I just can't figure out how it can be fermenting and not producing enough CO2 to bubble the airlock. I have read that gas production is not a great guide to fermentation rate but C6H12O6 -> 2 C2H5OH + 2 CO2 right? So if the glucose is being chomped by the yeast then there should be CO2 coming off!!??
I'm so confused. I've done 30 brews now but this is the first one I've done with an airlock or a constant temperature read-out. I'm learning a lot from it (like how much the wort heats itself) but this lack of CO2 seems so wrong - I've made wine before and the airlock is bubbling away for weeks or months if the fermentation is good.
Any advice much appreciated! The hops go in tonight - really hoping this batch works out well (the last one weren't too great :-/ Festival Celtic in a barrel that turned out to have a crack in it)

 

[foxbat]

Sounds like a healthy vigorous fermentation to me. Wait a few days and take another reading. My bet is it'll finish about 1.015 or 1.014 which is perfectly fine. The CO2 will be seeping out the sides of the lid.

Also, test your hydrometer in room temp water. Mine reads high by .003.

 

[LarryF]

The general rule is 2+2+2. 2 weeks fermenting, 2weeks warm conditioning indoors, 2 weeks cold conditioning in the shed (although this time of year is difficult). If you're dry hopping and you pitched the yeast on Saturday it might be a bit early to add the hops. I normally add my dry hop 9 days into fermentation when it's all died down and leave them for 5 days. Your fermentation sounds like it kicked off as expected and is going well. I have to admit that these days I take an OG reading and an FG reading and nothing in between, once I see a healthy Krausen after 24hrs I just leave it alone until I dry hop or bottle. One last thing.....STOP LIFTING THE LID TO LOOK AT IT. During the 2 week ferment I lift the lid for 2 or 3 seconds to slip the hop bag in and that's it. The next time is to have a quick sniff of the beer just before I bottle. The lid and the CO2 sitting here on top of the beer are what protect it from wild yeast and bacterial infections and from oxidation so I try to leave it all alone as much as I can.

 

[roxburd]

Cheers guys,

On the schedule for adding the hop pellets, I'm just following the kit instructions... happy to diverge from them though if there's a better way...

Must read up on dry hopping - no idea about that. The kit comes with the hops pressed into pellets which you just drop directly into the wort without stirring. It also provides a muslin bag to slip over the syphon tube to help filter them out (so they're left in the bin).

Yeah, I normally disturb the bin and lift the lid as little as possible - but when I was concerned that fermentation had stopped completely I figured it was best to take a gravity reading to see what was going on. Glad I did - at least I know there's a decent fermentation going on, even if I can't figure out where the CO2 is going - I guess it must be seeping out where the lid meets the bin. I've only ever used a bin with a plain lid before - I have to say this air lock seems like a complete waste of time, adding nothing more than an additional infection route!!

That's quite an error, foxbat - I'll check the hydrometer!

 

[simon12]

Unless the fermenter is rigid give it a squeeze and see if theres any airlock activity.

 

[roxburd]

Unless the fermenter is rigid give it a squeeze and see if theres any airlock activity.

Oh yeah, if I put a little pressure on the lid the air lock water shifts around.

So what I just tried just now is I placed an empty bottle on the lid - constant pressure. The water shifted round and then began to shift back!!! So yes, the CO2 is basically hissing out of either the grommet or where the lid meets the bin. So the airlock is a total waste of time!

Does everyone's bin do the same? How many people use an airlock? Seems like a really bad idea given the gas seeps out via the lid anyway and the airlock is just another potential source of infection.

 

[roxburd]

Just dropped the hops in and took the opportunity to take a gravity reading - 1.014. So it's gone down 0.003 in two days... and smells and tastes good too... so I guess it's all looking good.

Wont be using an airlock on a bin again though!

 

[thewelshwizard1]

Oh yeah, if I put a little pressure on the lid the air lock water shifts around.

So what I just tried just now is I placed an empty bottle on the lid - constant pressure. The water shifted round and then began to shift back!!! So yes, the CO2 is basically hissing out of either the grommet or where the lid meets the bin. So the airlock is a total waste of time!

Does everyone's bin do the same? How many people use an airlock? Seems like a really bad idea given the gas seeps out via the lid anyway and the airlock is just another potential source of infection.

What trap are you using six bubble or single? If using six bubble only put enough water noto past the second bubble as you will get over spill and it won't have enough release through the trap fella. Also watch out for lid leaks on the seals 👍

 

[roxburd]

What trap are you using six bubble or single? If using six bubble only put enough water noto past the second bubble as you will get over spill and it won't have enough release through the trap fella. Also watch out for lid leaks on the seals 👍

The first one was a single and I replaced that with a six-bubble when it filled up with foam. It was the six-bubble that had a really bad seam down the stem so I cleaned the single up and put that back in (1/4 of a Cambden tablet in the water each time and just enough water to give a good air-lock).

I reckon it must be the lid seal that the CO2 is leaking past. It's a new bin and the retailer specifically said in the sales blurb that the lid was gas-tight - will be raising that with them shortly...

 

[foxbat]

The phrase "gas tight" needs to be accompanied by "at XXX PSI" or else it's a meaningless statement.

 

[Brewed_Force]

I had the same thing happen with my last brew, a 10L Kolsch.
The Crossmyloof yeast took off like Vesuvius and filled the blow-off tube. When I cleaned and replaced it there was no bubbling.:wha:
What I hadn't figured was that the initial blow out had lifted the lid slightly, so I pressed it back on and used a couple of 3x2 offcuts to weigh it down.
Don't assume that the krausen will just blow out of the airlock, if its like mine it will find any route to escape!

 

[roxburd]

The phrase "gas tight" needs to be accompanied by "at XXX PSI" or else it's a meaningless statement.

From a physics perspective you're dead right.

From a legal perspective the Sale of Goods Act is very clear - products must be fit for the purpose for which they were sold. So whatever pressure it takes to bubble an airlock is the minimum pressure the bin should hold.

 

[roxburd]

I had the same thing happen with my last brew, a 10L Kolsch.
The Crossmyloof yeast took off like Vesuvius and filled the blow-off tube. When I cleaned and replaced it there was no bubbling.:wha:
What I hadn't figured was that the initial blow out had lifted the lid slightly, so I pressed it back on and used a couple of 3x2 offcuts to weigh it down.
Don't assume that the krausen will just blow out of the airlock, if its like mine it will find any route to escape!

Why the hell didn't I think of that!!?? Cheers Brewed_Force!!

 

[roxburd]

Why the hell didn't I think of that!!?? Cheers Brewed_Force!!

I now have a bench vice sitting on two 1cm-thick bits of hardboard spreading the load round the lid edge...