My yeast runs outta gas

[Shank]

I've brewed 4 partial mash batches. I'm having issues with my yeast not finishing the job. My last two batches I've get up to 1.068 OG. I pitch my yeast (Wyeast California Ale; I make starters where I will feed it some fresh wort and yeast nutrient, let it ferment for a few days, then pour off the old wort and put in another batch, ending up with a nice amount of yeast slurry that I then pitch). After 7-8 days fermentation activity has pretty much slowed down and cleared with a big yeast cake sitting on the bottom. Problem is my gravity at this point is only 1.026. I'm trying to get down to a 1.016 or even better. Why is my yeast stalling out?

Edit: I pour my cooled wort between fermenting buckets three times to aerate before pitching. Then I keep the carboy in the corner of my dining room where the temp stays around 68-75.

 

[thethirsty1]

What are your mash temps is it possible that yeast has done its work and you have a high amount of unfermentables

 

[pkeeler]

Here is a theory...

You have wort, add yeast. The yeast get to work, the hot and cold break settle out. Some yeast aren't as vigorous and they settle out quickly. But no matter, the good yeast are in suspension and reproducing and eating and having fun. But...then someone pours out the liquid and leaves the break and quick flocculating yeast. They add more wort. The non-active yeast reproduce a bit but their offspring are prone to quit early and flocculate, more trub is settled out.

Brewer sees all this trub and thinks it is all yeast slurry of good yeast, pitches it. But it consists of yeasts that were selected for early flocculation. His beers don't attenuate anywhere near what he would expect with normal yeast.

Possible?

 

[waldoar15]

Do you mean 2112? If it is, you're fermenting it too warm. Secondly, 7-8 days is a little early for a 1.070 beer. Chances are it will slowly chew down a few more points in another week. It's not uncommon for extract brews to stall at 1.020.

 

[pkeeler]

I assumed he meant 1056

 

[waldoar15]

I assumed he meant 1056

1056 is called "American Ale" by Wyeast, 2112, is "California Lager", White labs WLP 001 is called "California Ale".

I don't really know which one he's really using.

 

[Shank]

Thanks. I think I got confused because I was looking at Wyeast's website; I used White Labs 001 "California Ale". Would I get high amounts of unfermentables in the extract? I have heard that other people have the same problem using liquid malt extracts. If that's the case I will just have to pull the trigger soon and go all grain. I reckon I'll keep cutting the teeth on partial mash until I get the $$ together for all grain equipment.

It is totally possible I am throwing out the good yeast in suspension. But I've had this problem with 3 batches and have done each one different (same yeast though- WLP 001): 1st no yeast starter, just pitched straight from the tube; 2nd made yeast starter and pitched entire concoction into my wort; 3rd is the one I made a starter on a stir plate, fermented, put it in the fridge to settle all the yeast, poured off converted wort, poured on new wort, fermented, then pitched about 48 hours later.

I just racked it today to a secondary and will let it sit for another week or so before bottling. Should I have let it sit in the primary fermenter on that big pile of yeast and trub longer? It will still ferment in the secondary, correct?

I'm beginning to think it is an unfermentables problem. I've done everything I can think of to make bionic super yeast which should have a huge party in there and still have the issues with attenuation. Are some malt extracts more fermentable than others? Or should I just hurry up and go all grain (which I want to do anyway)?

 

[ScrewyBrewer]

All grain can only compound your problem, if you don't hit the correct mash temperatures you will produce wort with a higher amount of unfermentable sugars than you would find in any extracts.

I'm guessing that you cooled your wort and yeast slurry to 70F before pitching and then maintained the optimal temperature range of 68-73F during the initial fermentation phase.

 

[broadbill]

Not knowing anything about your mash process...I would agree with what waldoar15 said and its way to soon. Leave that puppy in the fermenter for another 2 weeks and see where you are at.

Just like bubbles in the airlock, sediment in the bottom of the fermenter doesn't mean a whole lot.

What temp are you fermenting at (what temp is the beer, NOT the room/ambient temp)? Lower temps...longer ferments...but cleaner tasting beer.

 

[jkreuze]

Since you're using extract and not going AG maybe you are a little low on free amino nitrogen--you might try adding yeast nutrient along with your starter next time (I know you are using nutrient in the starter, but maybe you could use some in the wort as well).

Here's the link to the Nutrients section of How To Brew
http://www.howtobrew.com/section1/chapter6-9-1.html

Not sure if that's your issue but it probably wouldn't hurt to give it a shot.

 

[motobrewer]

mash temp and recipe

 

[waldoar15]

I just racked it today to a secondary and will let it sit for another week or so before bottling. Should I have let it sit in the primary fermenter on that big pile of yeast and trub longer? It will still ferment in the secondary, correct?

I'm beginning to think it is an unfermentables problem. I've done everything I can think of to make bionic super yeast which should have a huge party in there and still have the issues with attenuation. Are some malt extracts more fermentable than others? Or should I just hurry up and go all grain (which I want to do anyway)?

You should have left it on the yeast. There's pretty much no reason (other than you're in a hurry) to rack your beer off of the yeast at a week, especially a 1.070 beer. You're not giving them the time to do their job.

 

[rcrabb22]

Another possible issue is raised in the new book, "Yeast: The Practical Guide to Beer Fermentation" by Chris White, Jamil Zainasheff. Yeast do not like varying temps and a 7 degree swing could be an issue. The yeast may get more active when it warms but when it cools they will begin to shut down and settle out. They promote the general rule of starting fermentation cooler and gradually raise temps during the process. Once the temperature has risen, temperature reduction hinders the yeast.

 

[millaj92]

I still do some extract batches sometimes when I don't have much time to dedicate to the brew day or if I'm giving someone a hands-on tutorial, and I've had some batches not go all the way when I know I'm doing everything right. I never thought about blaming it on the LME, but that makes perfect sense. Who-da thunk it...unfermentables in LHBS LME?

 

[mhenry41h]

Im not personally sold on the concept of too intensive of a starter. I think a good smack pack can accompish great things unless you are brewing a MEGA.