Stuck Fermentation: Agitation Helpful?

[Clint Yeastwood]

An ale I'm brewing has been sitting at 1.021, corrected for temperature, for 5 days. Zero movement.

Is there any hope agitating the fermenter will get it going? Because I just did that. It's a bucket. I took a hammer and beat the bottom of the bucket to knock the yeast loose, and then I shook it.

I plan to check the gravity tomorrow and see if anything happened. I may put a little bit of the beer in a bag with bread yeast and see if it tries to ferment.

 

[Clint Yeastwood]

I started at 1.057, and Beersmith thinks I should be at 1.017. Notes from old efforts show 1.010.

 

[BrewZer]

If you're going to leave it in the fermenter for another week or two, it shouldn't hurt anything. Just don't punch a hole in the bottom with your hammer.

 

[Clint Yeastwood]

I decided to try the bread yeast thing. I stuck beer in a bag with hydrated yeast, and I'm keeping it at 80 degrees. Don't know if this is smart, but it can't be any worse than pouring the sample down the toilet.

 

[hotbeer]

The thing to worry about for the bread yeast is that it might ferment out some of the sugars in the wort that we don't normally ferment out for beer. But I don't really know, I've never found anything conclusive about it's use for beer. Although is is the same variety (not necessarily the correct scientific term) as ale yeast.

However IMO, agitating the yeast is not any issue. I did it more routinely with the ales I've been brewing. I've got a porter going and it started at 1.058 and is sitting at 1.020. It looks like that's what it's going to stay even though the FG was predicted to be 1.014.

Might get a few more points in the 1 or 2 more weeks it's going to stay in the FV. But I'm not worried, the porter previous to that finished a tad higher, but it actually turned out pretty decent and not as sweet as I imagined it would be at that higher FG.

 

[Rish]

Rousing (which you did) and warming it up a few degrees may help. Shouldn't hurt it now.

 

[day_trippr]

[edit] Apparently some bread yeast can ferment maltotriose in addition to maltose. Color me surprised...

Cheers!

 

[Jag75]

Was this beer pressure fermented? One downside to pressure fermentation is that it could have a negative effect on yeast growth , more so in Ale yeast.

 

[Clint Yeastwood]

No pressure.

I gave up today and pitched a different yeast. I didn't make a starter, so I'm asking for trouble.

I saw someone recommending pitching the same yeast, but it seems to me that if it died once, it's more likely to do it again.

 

[Jag75]

It might have been done . Between 17 and 21 your only looking at 4 pts. Did you try it before you added that bread yeast?

 

[Clint Yeastwood]

It tastes fine, but here is the problem. I used a lot of crystal malt, so it's going to taste sweet no matter what. I can't tell fermentable sugar from unfermentable.

In the past, it went considerably lower, so that is a concern.

Yesterday I saw some Youtube beer guru testing hydrometers, and the results were horrifying. I would have thought a plain old glass hydrometer would have been pretty accurate, but he got very bad results. I would hope results would at least be repeatable. This is the same old hydrometer I've always used.

 

[camonick]

I used a lot of crystal malt, so it's going to taste sweet no matter what.

One should/ would expect a higher FG when “a lot” of crystal malt is involved. It was probably done.

 

[odie]

I have a pub ale that seemed to have stalled around 1.030 for a couple weeks. I shook the keg up real good and seems to be going again.

 

[Clint Yeastwood]

Incidentally, I solved the problem of bubbles messing up hydrometer readings. I took the hydrometer out twice and wiped it dry. Nearly all the bubbles went with it.

Now, does dissolved CO2 have a significant effect on specific gravity? No idea, but at least I can now tell the difference between "beer" and "not beer."

 

[camonick]

Another thing that would really help forum members help diagnose your issues with all of the questions you pose would be some recipe and process information in each post. Pictures are invaluable too. Beer style, batch size, grain types and quantities, mash temps and time , type of yeast and fermentation temperatures. Can all play a huge role in the finished beer and how it performs while it ferments. People can plug the information you give into their respective programs, and sometimes see something that you have overlooked. Without the above information, the responses are more or less guesses, leading to yet more questions and frustration.

 

[Clint Yeastwood]

A lethally boring paper I found on the web says dissolved CO2 makes water up to 3% more dense, so if you take a reading without getting all the gas out, and the reading is low enough to prove, in flat beer, that your desired FG has been reached, then you have gone down to, or passed, your desired FG. In other words, CO2 makes beer look heavier to a hydrometer.

 

[hotbeer]

Yesterday I saw some Youtube beer guru testing hydrometers, and the results were horrifying.

On the flip side of that, I've never had a hydrometer that tested as being off by more than a point. But I only check them for what they show water as. Never checked them against something else with a known SG. And certainly I haven't had many to check.

 

[BrewZer]

Incidentally, I solved the problem of bubbles messing up hydrometer readings. I took the hydrometer out twice and wiped it dry. Nearly all the bubbles went with it.

Now, does dissolved CO2 have a significant effect on specific gravity? No idea, but at least I can now tell the difference between "beer" and "not beer."

Remember to spin the hydrometer while in the sample. That should knock any bubbles off the sides.

 

[Clint Yeastwood]

Right now, this ale is going down the kitchen sink.

I repitched it and got nowhere. Twice. Then I decided to try yeast nutrient. I saw several sources saying a teaspoon per gallon was about right. I used about 80% of that figure. Later on, I saw much more modest figures. It's funny how you can Google pretty carefully and still get BS.

Now the beer tastes like yeast nutrient, which is like pretzels and salt ground up in a coffee grinder.

 

[IslandLizard]

I repitched it and got nowhere. Twice.

Pitching a sleeve of yeast into a hostile environment of relatively high % of alcohol plus low fermentable content is not going to resuscitate a potentially stalled or (nearly) finished fermentation that easily.
It requires selecting certain yeasts that are able to chew up what's left before dying from alcohol poisoning.

Keeping that in mind, super large pitches of actively fermenting starters are usually needed. Or alternatively by adding relatively small amounts to another still actively fermenting batch. Carefully dosing nutrients can assist in their survival, building up tolerance with each step/addition.

 

[mac_1103]

Just out of curiosity, has it done anything at all since you originally posted this, or is it still stuck at 1.021?

 

[Clint Yeastwood]

The second time I repitched, I used an active starter. No help. I'm going to look over the mash schedule.

 

[Clint Yeastwood]

Just out of curiosity, has it done anything at all since you originally posted this, or is it still stuck at 1.021?

Last reading was 1.019.

 

[odie]

I would have waited it out on the original yeast. My pub ale appears to still be fermenting after a month. It's slow but gravity seems to be moving down.