At what point do I worry about stuck fermentation?

[Mozart]

First, regarding the question above, after reading these forums, I'm pretty sure the answer is "not yet".

That said, here's my situation....

I'm on day 9 on the ferment of a hefeweizen, recipe OG 1.050, measured OG 1.054, recipe FG (per BeerSmith) 1.012.

Yeast used = White Labs Hefeweizen IV (WLP380). Amount pitched in 5 gallons wort = 1 vial. Pitching temp = 64*. Ferment temp through day 7 = 64*. On day 7 I raised ferment temp to 66* (as measured by insulated probe taped to my fermenter).

On day #2 of ferment I replaced my airlock with a blowoff tube because krausen had begun to rise into the airlock. Switched back to airlock a few days later. I definitely had a vigorous initial fermentation.

Based on what I've read, an ale should perhaps finish initial ferment in 7-10 days, and I'm sitting on day 9 and just took an SG reading in preparation for potential bottling.

It read 1.020, definitely too high, even if I did overshoot my OG a bit.

What I did today is bump up the temp another couple of degrees, to 68. I plan on taking another SG reading in a couple of days.

Ultimately though, and there *is* a question here, just wanted to keep the community for asking for more details, if after a couple of days I'm still at 1.020 SG, what do I do?

Of course, I can hear the answer now, "Why don't you wait a couple of days, and *then* ask us. We all bet you'll see a drop between now and then in SG, especially with the gradual rise in temp."

Ok... I can't help it... I'm still a noob. I'm *trying* to get the hang of RDWHAHB, and I'm better than I used to be, but not quite there just yet.

Cheers!

 

[Heavywalker]

Give the carboy a gentle swirl to suspend the yeast and see if they do their thing.

FWIW one vile of yeast is under pitching by about half of the amount that is needed for a beer of that gravity, I suspect that is where your problem started. Next time consider making a starter so help those yeasties along.

 

[Ravenshead]

Assuming this is an extract recipe, finishing at 1020 is not an uncommon problem. It's caused by the high temps used in creating the extract (high temps=more un-fermentable sugars). That said, you can try swirling the yeast gently but I'd guess if you don't see any more movement in a couple days, you're done. It'll still be a good beer, just a little sweet.

 

[Mozart]

Thanks to both of you for your input.

This was, indeed, an extract recipe, though if it turns out my beer is stuck at 1.020 it will be the first time I've encountered this problem (this is my fourth solo batch, and I've also brewed two more with a friend using extract).

If the beer holds steady at 1.020, is there a risk that when I add the priming sugar and bottle, the addition of the priming sugar will wake the yeast back up? If that happens and the beer ferments down to the recipe FG of 1.012-1.013 or so, I think that's bottle bomb territory.

Bottle bombs are the one thing I want to avoid at all costs as I can't imagine how I'd feel if someone actually got hurt from my homebrew.

Cheers!

 

[BansheeRider]

Depending how old the vial of yeast was its possible you didn't have enough cells to reach full attenuation. Yeastcalc.com will tell you how big of a starter you need depending on the age of the yeast and gravity of the wort. I make starters for every batch now and I average over 80% attenuation every time..

 

[progmac]

the only reliable way to get past a stuck ferment that i've heard is repitching on an entire yeast cake.

i've had some success adding another pound or so of fermentables and keeping the temperature high. but that is unlikely to get you down to 1.012.

i would put it in the warmest place in your house for now and hope for the best.

also make sure your hydrometer is properly calibrated. if you whipped up a quick batch of starsan to clean your thief and some was in the beer, that could also bump the SG significantly.

 

[Mozart]

I tried to gently swish my fermenting bucket and bumping the temperature a bit. Time will tell if that helps.

I suppose I could boil a pound of extract and add it and another vial of yeast to the beer and see if that does anything.

What I'm most concerned with though is fermentation picking back up again after I add priming sugar and bottle. Is this a real risk? Could the priming sugar kick-start the ferment? Last thing I want is bottle bombs.

 

[JoppaFarms]

This sounds like the exact problem I am facing right now with my American Wheat AG batch. 1.050 OG (1.051 actual), 1.012 FG (currently sitting at 1.024 at day 7 of fermentation). I raised the temperature 2 degrees (62 to 64). My yeast was the Wyeast 1010 but the smack pack wasn't in the package and the date printed was 59 days prior to brew day. My yeast definitely wasn't as healthy as it should be and I dont have the equipment to make a starter yet. I'll give it a swirl and see what happens by day 14. Hope yours picks up man!

 

[Rhumbline]

I've been brewing just extract kits. The process I've been using is to measure SG after one week, if I'm within 3-4 points of final gravity target I rack to secondary and bottle after another week.

If I'm not within 3-4 points I give it another week in primary. When I'm within 3-4 points I rack to secondary for a week before bottling. It's worked well for me so far.

 

[pfgonzo]

+1 to each response you've received so far. [Edit] Well, except for Rhumbline. Why rack when you're 3-4 pts from expected final gravity? Sounds like a recipe to stall fermentation. [/edit]

GENTLE swirling/stirring, accompanied by an increase of the temp to 75 or so may get you another couple of points. If you still have no movement after doing that, the yeast are done. Time to bottle and enjoy a hefe with slightly more body than you expected. It will be beer and I'm sure it will be delicious.

P.S. don't fret about the temp increase to 75. The vast majority of off flavor/esters/fusel formation occurs during the first 72 hours or so of fermentation (per Chris White), and that's the time to keep temps low. Chris White actually suggests bumping the temp up 5-8 degrees on all fermentations after the first ~4 days to ensure complete attenuation.

 

[Rhumbline]

+1 to each response you've received so far. [Edit] Well, except for Rhumbline. Why rack when you're 3-4 pts from expected final gravity? Sounds like a recipe to stall fermentation. [/edit]

...

Being a noob I just followed the kit instructions at first, it's worked fine so far so I'm not going to reinvent a perfectly good wheel. Why mess with success.

In my admittedly limited experience, if it gets within 3 points of the target FG then it ain't gonna stall. The secondary is just because I like looking at a big ol' jug of beer before it goes into bottles!

 

[duboman]

So here is my take....

Just because you've never had an extract batch finish at 1.020 doesn't mean it will never happen.

There are plenty of people brewing extract that have their beer finish at 1.020. It is common. You under pitched the beer and have no idea how fresh the extract used was.

If you raise the temp and swirl the yeast and give it a few days and still read 1.020. Give it another day or 2 and read again. If still no change, it's done.

All this assumes you are reading with a hydrometer that is calibrated and corrected the reading for temp. If you are using a refractometer then use a hydrometer.

Yes the priming sugar will cause re fermentation because that's what it's supposed to do and if the beer is at FG, it's the only ferment able in the bottle to prime. Bottle bombs occur because either the beer was not at FG, too much priming sugar was used or infection.

Racking to secondary is not a good idea before FG. Removing the beer from the majority of the yeast is not an ideal way to restart fermentation.

I would RDWHAHB.

 

[IslandLizard]

...an ale should perhaps finish initial ferment in 7-10 days, and I'm sitting on day 9...

You gave the answer already, it isn't done yet. Yeast and fermentation don't follow people's schedules. They have their own agenda.

As mentioned above, you probably under-pitched, so there was not that much healthy yeast to start with. But the fermentation started, so you're on your way. Swirling is a good method to bring yeast back into suspension. Do not rack it off your yeast cake, the yeast needs to do its thing, including clean-up. That takes time, and a healthy supply of yeast.

Let it ferment for 3 weeks in total and then measure gravity. And again 3 days later. If they match it is done.

Adding fermentables together with a new yeast starter at high krausen may make them chomp some of the older fermentables, but not necessarily.

I've had a few 1.070-1.075 extract batches finishing at 1.020-1.022, instead at their predicted 1.014. That's after 28 days!

If you added your extracts early in the boil, or they got scorched on the bottom, there could be quite a bit of caramelization in the wort, and that ups your FG.

 

[Mozart]

If you added your extracts early in the boil, or they got scorched on the bottom, there could be quite a bit of caramelization in the wort, and that ups your FG.

I added 2 lbs. of DME at the beginning of the boil, with the other 4 lbs. going in with 10 minutes left in the boil, so I don't think carameliation is the issue.

The more I think about it, it's likely the pitch.

Thinking back, I was preparing to make this beer the week before, and was bottling another batch that day too. So... I took the liquid yeast out of the fridge to warm up while I bottled. I ran out of time, however, and didn't end up getting to brew that day, so back in the fridge the vial of yeast went.

When I had to put the blowoff tube in on day #2 of ferment, I figured I hand't done the yeast terrible harm, but now I wonder. Still, that vigorous initial fermentation gives me pause as to what's going on.

I measured SG again today (2 days after the last reading) and it's holding at a nice, steady 1.020.

I'm considering options at this point.

I don't think a simple repitch would work. I've read that yeast like wort, not beer. I understand that yeast build up a tolerance to rising alcohol levels slowly. If so, by pitching yeast into beer, I figure I might just 'shock' them with the alcohol content.

Sounds a lot like keeping an aquarium. Fish can be hardy and adapt to changing water conditions, so long as they happen slowly.

Anyway, I'm considering 2 options at this point.

Option #1: Bottle 'er up this weekend. I'm leery of bottle bombs if that 1.020 SG beer decides it isn't done yet after it's gotten started on some priming sugar though. If I do bottle it, I'll 'bottle' it in recycled 5L mini-kegs I use. I figure if one of those over pressurizes, I won't have exploding glass, just a rubber stopper flying off and a big mess.

Option #2: Brew a small batch of beer, perhaps about a gallon, using similar yeast and extract. When that one starts to ferment vigorously, rack about a gallon of the stuck beer into it. After giving it several hours to adjust, rack more stuck beer into it, etc..

Hopefully the yeast in the small batch will have some tolerance for alcohol if they've started fermenting in the smaller batch, and by racking a portion at a time of the stuck beer into it, I won't change the chemistry (alcohol content) the yeasties are exposed to as drastically as I would if I just pitched yeast or even a starter into 5 gallons of stuck beer.

Anyway... guess I have a decision to make.

Thanks for all the input.

Cheers!