Fermentation stuck-more yeast?

[mdawson9]

Hey all, I brewed NB's winter warmer extract kit on 12/12 and gravity is stuck at 1.026. OG was 1.069. I probably pitched by just using the one pack of dry Nottingham that was included.
My question is, can I pitch another pack now I'm at 2 and a half weeks in the primary? Thanks for the input!!

 

[beerman0001]

What temp are you fermenting at?

 

[Demus]

When you say stuck, how many days has it been at 1.026? It may be slowly drifting down still even if you don't see any activity. Try warming it up a few degrees and giving it a swirl. Adding yeast is problematic 'cuz you'll likely get some O2 in there which is bad at this stage...

Also, what are you using for your reading? I used my refractometer for FG readings when I first got it without realizing it wasn't accurate with alcohol present. If that's what you did, take a sample with a hydrometer or look up the equation for refractometers for FG...

 

[mdawson9]

What temp are you fermenting at?

I've kept it around 64-66 F the whole time. 3 days ago after a gravity check I did shake the primary and let it go to 68-70 to try and revive but the gravity didn't move.

 

[mdawson9]

When you say stuck, how many days has it been at 1.026? It may be slowly drifting down still even if you don't see any activity. Try warming it up a few degrees and giving it a swirl. Adding yeast is problematic 'cuz you'll likely get some O2 in there which is bad at this stage...

Also, what are you using for your reading? I used my refractometer for FG readings when I first got it without realizing it wasn't accurate with alcohol present. If that's what you did, take a sample with a hydrometer or look up the equation for refractometers for FG...

First reading was Wednesday. Then last night. Both were 1.026. I use a hydrometer. I did try the swirl on Wednesday.

 

[unionrdr]

Swirl the fermenter,don't shake it at this point. O2 is your enemy after fermentation is started. At 1.069OG,more yeast would've been a good thing. That one packet may've gotten stressed with all that gravity.

 

[mdawson9]

Swirl the fermenter,don't shake it at this point. O2 is your enemy after fermentation is started. At 1.069OG,more yeast would've been a good thing. That one packet may've gotten stressed with all that gravity.

Thanks. I did do that but haven't seen signs of the yeast restarting. Maybe swirl once a day? Would that hurt or help?

 

[unionrdr]

Well,if you warmed it up,then swirled it a couple times already with no action a re-pitch may be needed. Does it test the same as before?

 

[Demus]

Thanks. I did do that but haven't seen signs of the yeast restarting. Maybe swirl once a day? Would that hurt or help?

Swirling shouldn't hurt as long as it's locked off from outside air. When you pitched, did you properly rehydrate the yeast or just sprinkle it in dry? Without proper rehydration dried yeast can have a pretty high death rate. Also, what is your aeration technique?

 

[mdawson9]

Well,if you warmed it up,then swirled it a couple times already with no action a re-pitch may be needed. Does it test the same as before?

It did test the same 2 days later.

 

[mdawson9]

Swirling shouldn't hurt as long as it's locked off from outside air. When you pitched, did you properly rehydrate the yeast or just sprinkle it in dry? Without proper rehydration dried yeast can have a pretty high death rate. Also, what is your aeration technique?

I made the mistake of not rehydrating. For aeration I shake up the bucket for a minute or so and then pitch.

 

[JLem]

I always wonder about the effectiveness of repitching. I'm not saying it won't work, but you better make sure you have a healthy crop of active yeast to repitch - you're going to be throwing them into very hostile conditions (low nutrient, low oxygen, high alcohol, low pH). I don't think you can just sprinkle in more dry yeast and expect much. I would make a starter and pitch it once you have an active fermentation going.

Stuck fermentations are generally a result of suboptimal starting conditions - underpitching, unhealthy yeast and low aeration. Assuming proper temperature, making sure you pitch enough, healthy yeast into a sufficiently aerated wort is your best bet against a stalled fermentation.

 

[Demus]

I made the mistake of not rehydrating. For aeration I shake up the bucket for a minute or so and then pitch.

Normally the cell count in a dry yeast packet is plenty, but when you sprinkle it directly into wort you kill about half of the cells so you are effectively underpitching. The cell walls burst because they are not meant to be filled with wort. Rehydrate with warm water (about 105) and a pinch of yeast nutrient. There's really no good reason to skip this simple step.
Aeration is your second problem. To quote "Yeast", by Chris White: 'Using proper levels of dissolved oxygen is just as important as using proper pitching rates (number of yeast cells). Lack of oxygen cause many fermentation problems. Stuck fermentations, long fermentation times, under-attenuated beers, yeast stress, and off flavors are often the result of too little oxygen". The proper amount is 8 to 10 PPM (parts per million). Since there's only 8 ppm in the air it's impossible to get any higher than 8 ppm using air. In tests they ran 5 minutes of shaking and splashing only resulted in 2.7 ppm, and you did even less than that. So basically you killed half the yeast and didn't give the survivors a healthy environment to do their work.
You only really have 2 options:
1- Give it a few weeks and hope for the best.
2- Make a starter and pitch more actively fermenting yeast without adding additional oxygen. Oxygen at this stage will lead to bad tasting, oxydized beer. This doesn't happen normally because the yeast absorb all the oxygen before (lag phase) they begin to ferment.

I'd recommend option 1 for you because a your first yeast starter shouldn't be done under the stress of "saving" a beer. Also, if you give it a few weeks to age on what yeast are in there they clean up much of the off flavors and it might turn out alright. Next time, if you rehydrate your yeast and aerate much more, you beer will definitely turn out better...

 

[unionrdr]

At this point I have to say that it looks like good,thorough aeration is just as important as proper reyhdrating (or starter for wet yeast). I rehydrated the last batch at 90F (PDF said 90-105F for rehydration water). Best yeast cream I've made to date. Been so cold/windy around here since Christmas the dang beer checked at 1.015 from 1.043OG. This after 3 weeks to the day last Saturday. Dang Company still hasn't paid me yet,so no heat to warm it with.

 

[Demus]

At this point I have to say that it looks like good,thorough aeration is just as important as proper reyhdrating (or starter for wet yeast). I rehydrated the last batch at 90F (PDF said 90-105F for rehydration water). Best yeast cream I've made to date. Been so cold/windy around here since Christmas the dang beer checked at 1.015 from 1.043OG. This after 3 weeks to the day last Saturday. Dang Company still hasn't paid me yet,so no heat to warm it with.

Add in temperature control and you have the whole equation! Attention to one variable without consideration of the others lowers any given beer's potential. Once a brewer has sanitation and basic process down, he/she should focus on the yeast. Far too many brewers move on to complicated recipes, hop schedules and all-grain before mastering the one thing that can make great beer, yeast!!

 

[rustym]

+1 on pitching more yeast, but you only need about a pint starter. Since your not trying to grow yeast just get the yeast active and pitch. They should gobble up whatever is left.

 

[chiteface]

Just following up. Did you repitch? Also how did/would you introduce the new yeast. Just dump. Or dump and swirl?

 

[mdawson9]

Just following up. Did you repitch? Also how did/would you introduce the new yeast. Just dump. Or dump and swirl?

I decided not to repitch. The beer is currently in a keg/secondary. Never dropped from 1.026. But it did taste good on kegging day.

 

[Demus]

I decided not to repitch. The beer is currently in a keg/secondary. Never dropped from 1.026. But it did taste good on kegging day.

1.069 to 1.026 is only 62% attenuation, so the beer may be a bit syrupy. This low attenuation is almost definitely the result of your aeration technique (1 minute of shaking). A properly aerated wort would very likely have done much better even without rehydrating. Yeast do amazing things under the right conditions, and one minute of shaking is not the right conditions by a large margin. The best solution in my opinion is oxygen injection. It's quick, effective and convenient and for $50 it pays bigger dividends to the quality of your brew than most other brew gear items costing more than twice as much. Also, a book every homebrewer owes himself to read is "Yeast", by Chris White and Jamil Zainishef. Ignore the info in there to your beer's detriment...

 

[matyas]

1.069 to 1.026 is only 62% attenuation, so the beer may be a bit syrupy. This low attenuation is almost definitely the result of your aeration technique (1 minute of shaking). A properly aerated wort would very likely have done much better even without rehydrating. Yeast do amazing things under the right conditions, and one minute of shaking is not the right conditions by a large margin.

So what is the best technique for aeration (barring oxygen injection)? I ask this as someone who may also be experiencing stuck fermentation.

 

[Demus]

So what is the best technique for aeration (barring oxygen injection)? I ask this as someone who may also be experiencing stuck fermentation.

The best technique in not to barr oxygen!! You can get close to the 8 ppm level if you shake and splash for a solid 20 minutes. You also get beefed up shoulders and biceps! An aquarium pump and stone will ease the workout, but won't cut much time. Only pure O2 can get you over 8 ppm, and gets you to 8 to 10 in about a minute in an average 1.050ish brew. Of all the things I've learned and tweaked and changed over the years in by brewing, this made the biggest difference in getting consistant results. It's well worth the extra money and ensures a good healthy ferment...