Underfermention Problem!

[paint_it_black]

Summary of long-winded post: FG came in way too high. Pitch more yeast and hope it'll ferment out properly?

...

A few weeks ago my dad (co-brewmaster) and I brewed our attempt at a Widmer Brrr (red ale/winter warmer). Let it ferment and clear in the primary for three weeks. I was at work when my dad was in the bottling process, so I wasn't there to witness, but here's what he said happened:

He took the final gravity reading, and it came up wayyy short -- like in the mid/high 1.02s. I don't have my records available right now, but the alcohol content should have been 5.5 to 6%, so figure the OG accordingly.
Unfortunately, he had already poured the corn sugar priming solution to the mix (just to clarify: the reading he took was of a sample PRIOR TO the addition of the corn sugar). So clearly he had two options: bottle it as is, or just leave it in the carboy and hope it'll continue to ferment. He chose the latter.
As expected, it bubbled slightly the following couple of days, which I would assume is the normal action you'd get form adding priming sugar. But, while I haven't taken a new gravity reading, I'm sure it can't be any lower than it was before the priming sugar was added.

What would you do in this situation? Clearly there's still a lot of unfermented sugar in there. Do we have a fighting chance if we pitch a new packet of yeast (Safale American Ale)? Or is it doomed to come out tasting wonky?

 

[carnevoodoo]

Just pitching more yeast will really not do it. Adding the priming sugar might actually help if the beer started fermenting again. What temperature is it at right now?

 

[paint_it_black]

About 68 F. Like I said, the priming sugar got it bubbling a bit for a couple days, but now there's no action in there.

 

[AnOldUR]

Let it ferment and clear in the primary for three weeks . . . he had two options . . . just leave it in the carboy and hope it'll continue to ferment. He chose the latter.

Did he add the priming sugar directly to the primary fermenter?

 

[paint_it_black]

No, he racked to a second carboy -- this is what we usually do for bottling, rather than using a "bottling bucket". Normally we would then fill the bottles from the new carboy with the recently siphoned beer and priming sugar mixed.
So he just popped an airlock on instead of bottling, and put it back in the closet.


However, if what you're getting at is trying to gauge how much yeast sediment is left in there, once he realized the underfermentation problem (which he discovered in the middle of siphoning to the new carboy), he made sure to suck up a good amount of trub so as to get more yeasties in there.)

 

[Nurmey]

Give it a while before you do anything. Sometimes racking will get those yeast going again and there is plenty of yeast left in suspension for it to ferment out.

It takes a few days for the yeast to build up enough to get going again. Since they have been given a little snack (bottling sugar) it may kick them in the butt a little faster.

 

[SurlyBastard]

Just because the airlock isn't doing anything doesn't mean the BEER isn't doing anything. The airlock will bubble but then stop, the yeast is still working, its just not producing enough gas to push the airlock up constantly. Typically, my us-05 is fairly constant, but most of the Belgian yeasts I use go NUTS and then stop...but doesn't mean they are done. I recently brewed a Belgian strong that came in at 1.022 after one week...the airlock was not bubbling...but another week came in at 1.013.

4 weeks in the primary, no secondary and bottle. gives the yeast time to clear the beer. Stop fussing with your beer

Cheers!

 

[Teromous]

Just because the airlock isn't doing anything doesn't mean the BEER isn't doing anything. The airlock will bubble but then stop, the yeast is still working, its just not producing enough gas to push the airlock up constantly. Typically, my us-05 is fairly constant, but most of the Belgian yeasts I use go NUTS and then stop...but doesn't mean they are done. I recently brewed a Belgian strong that came in at 1.022 after one week...the airlock was not bubbling...but another week came in at 1.013.

4 weeks in the primary, no secondary and bottle. gives the yeast time to clear the beer. Stop fussing with your beer

Cheers!

I agree with this. Near the end there is less activity visible in the airlock and you will see less movement of sediment in your fermenter, but it does not mean it's done. I sometimes tilt my primary a bit to give it some momentum and kick up the lees/trub. Racking to a secondary will similarly kick up the yeast and re-start fermentation as well as off-gas some of the CO2, so you will traditionally see some movement in the secondary when you transfer...but don't think it's done again when it stops in the secondary as well. Just wait it out a bit because patiently leaving it in a secondary, you have the advantage of leaving it there for a very long time before needing to take it out and bottle.

If you notice you gravity does not change at all, you are very correct in that you can add yeast. Some people even use a stronger yeast to finish or bottle their beer to assure proper carbonation levels as well as add more complexity to the beer.

 

[marcycaulkins]

did you use laaglander malt extract? I had a wicked problem with stuck ferments when i used that crap, it is just poorly fermentable.
most common causes of stuck ferment are poorly fermentable wort, temperature too low, poor oxygenation in the wort. or if it is high gravity, maybe the yeast just wasn't the right variety to tolerate the alcohol content and ferment completely.

good luck, i hope yours turns out, I had to dump 2 batches because of the crappy extract, and went back to AG. No probs since.

 

[paint_it_black]

Hmm, I don't think any of those were the problem. It's all-grain, so it wasn't anything to do with malt extract. The temperature, if anything, was a few degrees higher than it should have been, so it wasn't too low. And we WANTED it to be higher gravity, but we kind of missed our target and it came out pretty regular-ol gravity.

 

[Yooper]

Hmm, I don't think any of those were the problem. It's all-grain, so it wasn't anything to do with malt extract. The temperature, if anything, was a few degrees higher than it should have been, so it wasn't too low. And we WANTED it to be higher gravity, but we kind of missed our target and it came out pretty regular-ol gravity.

Well, if you fermented at a higher temperature, you'll get a less fermentable more dextrinous wort. When I want a beer to finish with a high FG I mash at 156-158. That way it will still have plenty of sweetness when it's done. If you fermented "a few degrees higher than it should have been", I would be willing to bet that is why it finished higher than you planned.

I brewed today, and used a mash temp of 153 for a "medium" fermentable wort. For a very fermentable wort, I have mashed as low as 147. Usually, only "thick" sweeter brews get mashed higher than 154 at my house.

 

[SurlyBastard]

I take it you wanted it to be higher gravity because you wanted it sweet?

I don't mess with the final gravity if I am trying to make a beer a little sweet, I will add either Lactose or Brown Sugar, depending on the brew I am making.

In this case, since the priming sugar was added, it will do its thing and then stop; if it is still too high, you can certainly add a couple grams of rehydrated dry yeast, but chances are you will end up too low and not have any sweetness to your beer.

As far as tasting funky, I don't know. I have added champagne yeast to a couple of very strong brews that I made, just to finish it off and had no off flavors, but I have not added regular yeast to finish off a normal brew. I would have to say that there would not be any off flavors, but thats just my opinion ^^

GL!

 

[Yooper]

What would you do in this situation? Clearly there's still a lot of unfermented sugar in there. Do we have a fighting chance if we pitch a new packet of yeast (Safale American Ale)? Or is it doomed to come out tasting wonky?

I guess I didn't answer your question. If you mashed at a high mash temp, the beer is finished. More yeast will not help. They will only eat the fermentable sugars. Safale yeast is highly attenuative usually, so I believe the beer is finished.

 

[paint_it_black]

Ummm, woops! Sorry guys! We effed up. I seemed to recall our OG came in way short, when in actuality, now that I refer to my notes, we overshot it by .002. Target was 1.071, we got 1.073. We never do bigger beers, so, not referring to our notes on the OG, we assumed it needed to finish somewhere in the 1.01s. Turns out, with the FG fo 1.23, it was already done, at a nice 6.5% alc/vol. It was purely our negligence which led us to second guess ourselves and think something was wrong.
Unfortunately, things happened as they happened, and our priming sugar got added. Now, one week later, I've checked the gravity and it's 1.022, so it's ready to bottle, which we will do this weekend. I just hope that having added that extra sugar won't have altered the taste too much. The sample tasted decent, but I had just eaten a steak and drank an ESB, so my taste buds were a little tainted...