Stout Fermentation

[Drew & Jeff]

We are new to homebrewing and this is our first stout. After nearly 24 hours the airlock is not bubbling. It is our first brew in a second-hand vat that was given to us. We replaced the seals and are fairly sure that it is airtight. Is it standard for stouts to take longer to begin fermentation? An SG reading suggests that it has begun (OG 1045 - SG 1038). It is a 21 litre mix using Cooper's stout, 1.5kg of dark liquid malt extract and 7g of supplied cooper's brewing yeast. We have not given up hope as it seems OK, but can anyone offer any suggestions?

[wombat]

first of all, if it doesn't seem to be fermenting yet - don't open it up. the last thing you want to do is infect your wort before your yeast can defend it.

just check a couple of basics first:
- what temperature was your brew when you added your yeast? too high can kill your yeast, too cold can shock it and keep it dormant.
- is your fermenter sealed correctly? fermentation might actually be happening but the airlock isn't moving. check this buy squeezing on the fermenter a little bit until the airlock bubble begins to move - then hold it and see if it levels itself out by means of an air leak. check the gravity of your brew and see if it has changed. if it's only leaking a little bit (not a gaping hole), then don't worry about it until after you've finished your brew - remember, you don't want to infect it.
- how old was the yeast?

i'd expect an FG of about 1014 with those ingredients. i would've also expected the SG to be more like 1054-1055 so perhaps, nuts to my theory...

if it gets stuck, remember, there is an abundant supply of quality cooper's yeast at the bottle shop in those bottles of best extra stout

-wombat

[Dogger Dan]

It sounds a lot like a stuck fermentation, I am wondering if it was aerated enough.

I am not sure on these keg designs, is there enough room to slosh the wort around and get the air mixed up in it so the yeast can fire up. Remember the first stage of yeast development is aerobic, it isn't to the latter stages that it becomes anerobic.

I only mention this because we seem to have had a lot of posts on slow slugish fermentations and it all seems to be with these vats which leads me to wonder if there isn't design issue. It doesn't seem to be stuck to anyone one brand of beer so I would question the number of Dud yeasts. I mean sure there are a few of those but this seems to be a bit to many and would result in big issues for the yeast supplier.

As an aside, since I switched to all grain and am running my boiling wort through a heat exchenger into the primary, I don't get the aeration I did when using a kit and dumping it and cold water into the primary. This has lead to a couple of slow fermentations, so I have had to ensure some vigorus stirring to get the air in.

Dogger

[Matty]

24hrs isn't really all that long for fermentation to kick off. I've had brews that took 2-3 days to get going. Alot depends on the yeast and the temp of the wort you are fermenting. If it's not warm enough it can be really slow. A slow brewed beer is good, but you do want it to start pretty quickly to reduce lag time and risk of infection.
I wouldn't panic just yet......

Cheers,

Matty

[Oliver]

Guys,

You might want to check out this thread for some other tips.

http://www.homebrewandbeer.com/forum/viewtopic.php?t=17

Cheers,

Oliver

[Drew & Jeff]

Thanks everybody for your input.
Well here's what happened, you might find this interesting too. After a day and a half of no apparent action, we discovered that there was in fact an air leak in the lid of the vat.
However, once we stimulated the vat a little it soon began bubbling, and violently. To a point where foam was coming out through the airlock. After about 6 hours of this, constantly refilling the airlock, it slowed to a more normal pace. After another 12 hours, it stopped bubbling completely again.
The brew is still in the vat, a week and a half on and it seems, going by gravity readings that fermenation has stopped. Unfortunately the reading is 1.020, not the desired 1.010 - 1.015. By my calculations that is a 4% stout. Not very good. Will leave it a few more days just in case.
Thanks again everybody, we will let you know how it turns out, if you're interested. I am still fearing infection, although it seems to taste ok.

[Matty]

Hey Drew & Jeff,
If you have, or can get your hands on, a second fermenter, then you can rack your brew and leave it for another week or so. Racking seems to get everything moving again and also helps to get a few more gravity points, as well as helping to clear the brew.
Just an idea if it helps.

Cheers,

Matty

[Shaun]

I have seen this question many times "The air lock is not bubbling has fermentation started" or at the other end of fermentation "The air lock has stoped bubbling does that mean it has finished fermenting".

There is only one answer to both these questions. NEVER BELIVE THE AIR LOCK!!!!!!!!! It is only a guild. The only way to tell if a beer is fermenting is to take an SG reading if the SG reading has not changed over a period of 48 hours the beer has not start or has finished fermenting. Depending on the yeast used and the temperature brewed at will vary the speed of fermentation. Using Lager yeast at a low temperature (11-13deg) your air lock may only bubble once every 12 - 24 hours (a long time to sit waiting for it to bubble).

So there are many reasons why the air lock may not bubble, however tempted you are do not believe it. Always always take an SG reading, if it is the same 48 hours apart there is no fermentation.

Just again do not rely on air locks take SG readings!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

There are brewers who do not use a lid and air lock, they cover the top of the fermentor with gladwrap held on with a rubber band and some pin sized holes in the gladwrap to let out the gasses.

Shaun